[7768b8d] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2019 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // ready_queue.cfa -- |
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| 8 | // |
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| 9 | // Author : Thierry Delisle |
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| 10 | // Created On : Mon Nov dd 16:29:18 2019 |
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| 11 | // Last Modified By : |
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| 12 | // Last Modified On : |
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| 13 | // Update Count : |
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| 14 | // |
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| 15 | |
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| 16 | #define __cforall_thread__ |
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[1b143de] | 17 | // #define __CFA_DEBUG_PRINT_READY_QUEUE__ |
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[7768b8d] | 18 | |
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[7a2972b9] | 19 | // #define USE_MPSC |
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[1eb239e4] | 20 | |
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[9cc3a18] | 21 | #define USE_RELAXED_FIFO |
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| 22 | // #define USE_WORK_STEALING |
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| 23 | |
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[7768b8d] | 24 | #include "bits/defs.hfa" |
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| 25 | #include "kernel_private.hfa" |
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| 26 | |
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| 27 | #define _GNU_SOURCE |
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| 28 | #include "stdlib.hfa" |
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[61d7bec] | 29 | #include "math.hfa" |
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[7768b8d] | 30 | |
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[04b5cef] | 31 | #include <unistd.h> |
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| 32 | |
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[13c5e19] | 33 | #include "ready_subqueue.hfa" |
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| 34 | |
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[7768b8d] | 35 | static const size_t cache_line_size = 64; |
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| 36 | |
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[dca5802] | 37 | // No overriden function, no environment variable, no define |
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| 38 | // fall back to a magic number |
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| 39 | #ifndef __CFA_MAX_PROCESSORS__ |
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[b388ee81] | 40 | #define __CFA_MAX_PROCESSORS__ 1024 |
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[dca5802] | 41 | #endif |
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[7768b8d] | 42 | |
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[9cc3a18] | 43 | #if defined(USE_RELAXED_FIFO) |
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| 44 | #define BIAS 4 |
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| 45 | #define READYQ_SHARD_FACTOR 4 |
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| 46 | #elif defined(USE_WORK_STEALING) |
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| 47 | #define READYQ_SHARD_FACTOR 2 |
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| 48 | #else |
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| 49 | #error no scheduling strategy selected |
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| 50 | #endif |
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| 51 | |
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| 52 | static inline [unsigned, bool] idx_from_r(unsigned r, unsigned preferred); |
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| 53 | static inline struct $thread * try_pop(struct cluster * cltr, unsigned w); |
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| 54 | static struct $thread * try_pop(struct cluster * cltr, unsigned i, unsigned j); |
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| 55 | |
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[04b5cef] | 56 | |
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[dca5802] | 57 | // returns the maximum number of processors the RWLock support |
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[7768b8d] | 58 | __attribute__((weak)) unsigned __max_processors() { |
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| 59 | const char * max_cores_s = getenv("CFA_MAX_PROCESSORS"); |
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| 60 | if(!max_cores_s) { |
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[504a7dc] | 61 | __cfadbg_print_nolock(ready_queue, "No CFA_MAX_PROCESSORS in ENV\n"); |
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[dca5802] | 62 | return __CFA_MAX_PROCESSORS__; |
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[7768b8d] | 63 | } |
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| 64 | |
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| 65 | char * endptr = 0p; |
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| 66 | long int max_cores_l = strtol(max_cores_s, &endptr, 10); |
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| 67 | if(max_cores_l < 1 || max_cores_l > 65535) { |
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[504a7dc] | 68 | __cfadbg_print_nolock(ready_queue, "CFA_MAX_PROCESSORS out of range : %ld\n", max_cores_l); |
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[dca5802] | 69 | return __CFA_MAX_PROCESSORS__; |
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[7768b8d] | 70 | } |
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| 71 | if('\0' != *endptr) { |
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[504a7dc] | 72 | __cfadbg_print_nolock(ready_queue, "CFA_MAX_PROCESSORS not a decimal number : %s\n", max_cores_s); |
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[dca5802] | 73 | return __CFA_MAX_PROCESSORS__; |
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[7768b8d] | 74 | } |
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| 75 | |
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| 76 | return max_cores_l; |
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| 77 | } |
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| 78 | |
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| 79 | //======================================================================= |
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| 80 | // Cluster wide reader-writer lock |
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| 81 | //======================================================================= |
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[b388ee81] | 82 | void ?{}(__scheduler_RWLock_t & this) { |
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[7768b8d] | 83 | this.max = __max_processors(); |
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| 84 | this.alloc = 0; |
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| 85 | this.ready = 0; |
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| 86 | this.lock = false; |
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| 87 | this.data = alloc(this.max); |
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| 88 | |
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| 89 | /*paranoid*/ verify( 0 == (((uintptr_t)(this.data )) % 64) ); |
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| 90 | /*paranoid*/ verify( 0 == (((uintptr_t)(this.data + 1)) % 64) ); |
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| 91 | /*paranoid*/ verify(__atomic_is_lock_free(sizeof(this.alloc), &this.alloc)); |
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| 92 | /*paranoid*/ verify(__atomic_is_lock_free(sizeof(this.ready), &this.ready)); |
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| 93 | |
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| 94 | } |
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[b388ee81] | 95 | void ^?{}(__scheduler_RWLock_t & this) { |
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[7768b8d] | 96 | free(this.data); |
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| 97 | } |
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| 98 | |
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[9b1dcc2] | 99 | void ?{}( __scheduler_lock_id_t & this, __processor_id_t * proc ) { |
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[7768b8d] | 100 | this.handle = proc; |
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| 101 | this.lock = false; |
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[64a7146] | 102 | #ifdef __CFA_WITH_VERIFY__ |
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| 103 | this.owned = false; |
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| 104 | #endif |
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[7768b8d] | 105 | } |
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| 106 | |
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| 107 | //======================================================================= |
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| 108 | // Lock-Free registering/unregistering of threads |
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[a33c113] | 109 | void register_proc_id( struct __processor_id_t * proc ) with(*__scheduler_lock) { |
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[b388ee81] | 110 | __cfadbg_print_safe(ready_queue, "Kernel : Registering proc %p for RW-Lock\n", proc); |
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[504a7dc] | 111 | |
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[7768b8d] | 112 | // Step - 1 : check if there is already space in the data |
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| 113 | uint_fast32_t s = ready; |
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| 114 | |
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| 115 | // Check among all the ready |
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| 116 | for(uint_fast32_t i = 0; i < s; i++) { |
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[9b1dcc2] | 117 | __processor_id_t * null = 0p; // Re-write every loop since compare thrashes it |
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[7768b8d] | 118 | if( __atomic_load_n(&data[i].handle, (int)__ATOMIC_RELAXED) == null |
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| 119 | && __atomic_compare_exchange_n( &data[i].handle, &null, proc, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) { |
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| 120 | /*paranoid*/ verify(i < ready); |
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[64a7146] | 121 | /*paranoid*/ verify(0 == (__alignof__(data[i]) % cache_line_size)); |
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[7768b8d] | 122 | /*paranoid*/ verify((((uintptr_t)&data[i]) % cache_line_size) == 0); |
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[a33c113] | 123 | proc->id = i; |
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[7768b8d] | 124 | } |
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| 125 | } |
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| 126 | |
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[b388ee81] | 127 | if(max <= alloc) abort("Trying to create more than %ud processors", __scheduler_lock->max); |
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[7768b8d] | 128 | |
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| 129 | // Step - 2 : F&A to get a new spot in the array. |
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| 130 | uint_fast32_t n = __atomic_fetch_add(&alloc, 1, __ATOMIC_SEQ_CST); |
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[b388ee81] | 131 | if(max <= n) abort("Trying to create more than %ud processors", __scheduler_lock->max); |
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[7768b8d] | 132 | |
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| 133 | // Step - 3 : Mark space as used and then publish it. |
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[9b1dcc2] | 134 | __scheduler_lock_id_t * storage = (__scheduler_lock_id_t *)&data[n]; |
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[7768b8d] | 135 | (*storage){ proc }; |
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[fd9b524] | 136 | while() { |
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[7768b8d] | 137 | unsigned copy = n; |
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| 138 | if( __atomic_load_n(&ready, __ATOMIC_RELAXED) == n |
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| 139 | && __atomic_compare_exchange_n(&ready, ©, n + 1, true, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) |
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| 140 | break; |
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[fd9b524] | 141 | Pause(); |
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[7768b8d] | 142 | } |
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| 143 | |
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[1b143de] | 144 | __cfadbg_print_safe(ready_queue, "Kernel : Registering proc %p done, id %lu\n", proc, n); |
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[504a7dc] | 145 | |
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[7768b8d] | 146 | // Return new spot. |
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| 147 | /*paranoid*/ verify(n < ready); |
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[37ba662] | 148 | /*paranoid*/ verify(__alignof__(data[n]) == (2 * cache_line_size)); |
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[7768b8d] | 149 | /*paranoid*/ verify((((uintptr_t)&data[n]) % cache_line_size) == 0); |
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[a33c113] | 150 | proc->id = n; |
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[7768b8d] | 151 | } |
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| 152 | |
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[a33c113] | 153 | void unregister_proc_id( struct __processor_id_t * proc ) with(*__scheduler_lock) { |
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[7768b8d] | 154 | unsigned id = proc->id; |
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| 155 | /*paranoid*/ verify(id < ready); |
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| 156 | /*paranoid*/ verify(proc == __atomic_load_n(&data[id].handle, __ATOMIC_RELAXED)); |
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| 157 | __atomic_store_n(&data[id].handle, 0p, __ATOMIC_RELEASE); |
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[504a7dc] | 158 | |
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| 159 | __cfadbg_print_safe(ready_queue, "Kernel : Unregister proc %p\n", proc); |
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[7768b8d] | 160 | } |
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| 161 | |
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| 162 | //----------------------------------------------------------------------- |
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| 163 | // Writer side : acquire when changing the ready queue, e.g. adding more |
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| 164 | // queues or removing them. |
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[b388ee81] | 165 | uint_fast32_t ready_mutate_lock( void ) with(*__scheduler_lock) { |
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[8fc652e0] | 166 | /* paranoid */ verify( ! __preemption_enabled() ); |
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[62502cc4] | 167 | |
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[7768b8d] | 168 | // Step 1 : lock global lock |
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| 169 | // It is needed to avoid processors that register mid Critical-Section |
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| 170 | // to simply lock their own lock and enter. |
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| 171 | __atomic_acquire( &lock ); |
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| 172 | |
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| 173 | // Step 2 : lock per-proc lock |
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| 174 | // Processors that are currently being registered aren't counted |
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| 175 | // but can't be in read_lock or in the critical section. |
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| 176 | // All other processors are counted |
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| 177 | uint_fast32_t s = ready; |
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| 178 | for(uint_fast32_t i = 0; i < s; i++) { |
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| 179 | __atomic_acquire( &data[i].lock ); |
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| 180 | } |
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| 181 | |
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[8fc652e0] | 182 | /* paranoid */ verify( ! __preemption_enabled() ); |
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[7768b8d] | 183 | return s; |
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| 184 | } |
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| 185 | |
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[b388ee81] | 186 | void ready_mutate_unlock( uint_fast32_t last_s ) with(*__scheduler_lock) { |
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[8fc652e0] | 187 | /* paranoid */ verify( ! __preemption_enabled() ); |
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[62502cc4] | 188 | |
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[7768b8d] | 189 | // Step 1 : release local locks |
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| 190 | // This must be done while the global lock is held to avoid |
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| 191 | // threads that where created mid critical section |
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| 192 | // to race to lock their local locks and have the writer |
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| 193 | // immidiately unlock them |
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| 194 | // Alternative solution : return s in write_lock and pass it to write_unlock |
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| 195 | for(uint_fast32_t i = 0; i < last_s; i++) { |
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| 196 | verify(data[i].lock); |
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| 197 | __atomic_store_n(&data[i].lock, (bool)false, __ATOMIC_RELEASE); |
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| 198 | } |
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| 199 | |
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| 200 | // Step 2 : release global lock |
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| 201 | /*paranoid*/ assert(true == lock); |
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| 202 | __atomic_store_n(&lock, (bool)false, __ATOMIC_RELEASE); |
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[62502cc4] | 203 | |
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[8fc652e0] | 204 | /* paranoid */ verify( ! __preemption_enabled() ); |
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[7768b8d] | 205 | } |
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| 206 | |
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| 207 | //======================================================================= |
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[9cc3a18] | 208 | // Cforall Ready Queue used for scheduling |
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[b798713] | 209 | //======================================================================= |
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| 210 | void ?{}(__ready_queue_t & this) with (this) { |
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[28d73c1] | 211 | lanes.data = 0p; |
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[9cc3a18] | 212 | lanes.tscs = 0p; |
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[28d73c1] | 213 | lanes.count = 0; |
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[b798713] | 214 | } |
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| 215 | |
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| 216 | void ^?{}(__ready_queue_t & this) with (this) { |
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[39fc03e] | 217 | verify( 1 == lanes.count ); |
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[dca5802] | 218 | free(lanes.data); |
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[9cc3a18] | 219 | free(lanes.tscs); |
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[dca5802] | 220 | } |
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| 221 | |
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[64a7146] | 222 | //----------------------------------------------------------------------- |
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[9cc3a18] | 223 | __attribute__((hot)) void push(struct cluster * cltr, struct $thread * thrd) with (cltr->ready_queue) { |
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[61d7bec] | 224 | __cfadbg_print_safe(ready_queue, "Kernel : Pushing %p on cluster %p\n", thrd, cltr); |
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[1b143de] | 225 | |
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[5cb51502] | 226 | const bool external = (!kernelTLS().this_processor) || (cltr != kernelTLS().this_processor->cltr); |
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[9cc3a18] | 227 | /* paranoid */ verify(external || kernelTLS().this_processor->cltr_id < lanes.count ); |
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[fd1f65e] | 228 | |
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[dca5802] | 229 | // write timestamp |
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[b798713] | 230 | thrd->link.ts = rdtscl(); |
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| 231 | |
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[9cc3a18] | 232 | bool local; |
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| 233 | int preferred = external ? -1 : kernelTLS().this_processor->cltr_id; |
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[52769ba] | 234 | |
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[dca5802] | 235 | // Try to pick a lane and lock it |
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| 236 | unsigned i; |
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| 237 | do { |
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| 238 | // Pick the index of a lane |
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[5fe7322] | 239 | unsigned r = __tls_rand_fwd(); |
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[772411a] | 240 | [i, local] = idx_from_r(r, preferred); |
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| 241 | |
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[04b5cef] | 242 | i %= __atomic_load_n( &lanes.count, __ATOMIC_RELAXED ); |
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[b798713] | 243 | |
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| 244 | #if !defined(__CFA_NO_STATISTICS__) |
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[fd1f65e] | 245 | if(external) { |
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| 246 | if(local) __atomic_fetch_add(&cltr->stats->ready.pick.ext.local, 1, __ATOMIC_RELAXED); |
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| 247 | __atomic_fetch_add(&cltr->stats->ready.pick.ext.attempt, 1, __ATOMIC_RELAXED); |
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| 248 | } |
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| 249 | else { |
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| 250 | if(local) __tls_stats()->ready.pick.push.local++; |
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| 251 | __tls_stats()->ready.pick.push.attempt++; |
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| 252 | } |
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[b798713] | 253 | #endif |
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| 254 | |
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[7a2972b9] | 255 | #if defined(USE_MPSC) |
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| 256 | // mpsc always succeeds |
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| 257 | } while( false ); |
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| 258 | #else |
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[b798713] | 259 | // If we can't lock it retry |
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[dca5802] | 260 | } while( !__atomic_try_acquire( &lanes.data[i].lock ) ); |
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[7a2972b9] | 261 | #endif |
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[b798713] | 262 | |
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[dca5802] | 263 | // Actually push it |
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[5fe7322] | 264 | push(lanes.data[i], thrd); |
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[dca5802] | 265 | |
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[7a2972b9] | 266 | #if !defined(USE_MPSC) |
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| 267 | // Unlock and return |
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| 268 | __atomic_unlock( &lanes.data[i].lock ); |
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| 269 | #endif |
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[dca5802] | 270 | |
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[c426b03] | 271 | // Mark the current index in the tls rng instance as having an item |
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| 272 | __tls_rand_advance_bck(); |
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| 273 | |
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[1b143de] | 274 | __cfadbg_print_safe(ready_queue, "Kernel : Pushed %p on cluster %p (idx: %u, mask %llu, first %d)\n", thrd, cltr, i, used.mask[0], lane_first); |
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| 275 | |
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[dca5802] | 276 | // Update statistics |
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| 277 | #if !defined(__CFA_NO_STATISTICS__) |
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[fd1f65e] | 278 | if(external) { |
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| 279 | if(local) __atomic_fetch_add(&cltr->stats->ready.pick.ext.lsuccess, 1, __ATOMIC_RELAXED); |
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| 280 | __atomic_fetch_add(&cltr->stats->ready.pick.ext.success, 1, __ATOMIC_RELAXED); |
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| 281 | } |
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| 282 | else { |
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| 283 | if(local) __tls_stats()->ready.pick.push.lsuccess++; |
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| 284 | __tls_stats()->ready.pick.push.success++; |
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| 285 | } |
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[dca5802] | 286 | #endif |
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[b798713] | 287 | } |
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| 288 | |
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[13c5e19] | 289 | // Pop from the ready queue from a given cluster |
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| 290 | __attribute__((hot)) $thread * pop(struct cluster * cltr) with (cltr->ready_queue) { |
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| 291 | /* paranoid */ verify( lanes.count > 0 ); |
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[9cc3a18] | 292 | /* paranoid */ verify(kernelTLS().this_processor->cltr_id < lanes.count ); |
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| 293 | |
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[1eb239e4] | 294 | unsigned count = __atomic_load_n( &lanes.count, __ATOMIC_RELAXED ); |
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[9cc3a18] | 295 | int preferred = kernelTLS().this_processor->cltr_id; |
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[13c5e19] | 296 | |
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[772411a] | 297 | |
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[13c5e19] | 298 | // As long as the list is not empty, try finding a lane that isn't empty and pop from it |
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[78d6c803] | 299 | for(25) { |
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[13c5e19] | 300 | // Pick two lists at random |
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[5fe7322] | 301 | unsigned ri = __tls_rand_bck(); |
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| 302 | unsigned rj = __tls_rand_bck(); |
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[772411a] | 303 | |
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| 304 | unsigned i, j; |
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| 305 | __attribute__((unused)) bool locali, localj; |
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| 306 | [i, locali] = idx_from_r(ri, preferred); |
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| 307 | [j, localj] = idx_from_r(rj, preferred); |
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| 308 | |
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| 309 | #if !defined(__CFA_NO_STATISTICS__) |
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[3143f28] | 310 | if(locali && localj) { |
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[772411a] | 311 | __tls_stats()->ready.pick.pop.local++; |
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[13c5e19] | 312 | } |
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| 313 | #endif |
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| 314 | |
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[1eb239e4] | 315 | i %= count; |
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| 316 | j %= count; |
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[13c5e19] | 317 | |
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| 318 | // try popping from the 2 picked lists |
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| 319 | struct $thread * thrd = try_pop(cltr, i, j); |
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[52769ba] | 320 | if(thrd) { |
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[9cc3a18] | 321 | #if !defined(__CFA_NO_STATISTICS__) |
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[772411a] | 322 | if( locali || localj ) __tls_stats()->ready.pick.pop.lsuccess++; |
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[52769ba] | 323 | #endif |
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| 324 | return thrd; |
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| 325 | } |
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[13c5e19] | 326 | } |
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| 327 | |
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| 328 | // All lanes where empty return 0p |
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| 329 | return 0p; |
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| 330 | } |
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| 331 | |
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[9cc3a18] | 332 | static void fix_times( struct cluster * cltr ) with( cltr->ready_queue ) { |
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| 333 | lanes.tscs = alloc(lanes.count, lanes.tscs`realloc); |
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| 334 | for(i; lanes.count) { |
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| 335 | lanes.tscs[i].tv = ts(lanes.data[i]); |
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[1eb239e4] | 336 | } |
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| 337 | |
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| 338 | } |
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| 339 | |
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[9cc3a18] | 340 | //======================================================================= |
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| 341 | // Various Ready Queue utilities |
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| 342 | //======================================================================= |
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| 343 | // these function work the same or almost the same |
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| 344 | // whether they are using work-stealing or relaxed fifo scheduling |
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[1eb239e4] | 345 | |
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[b798713] | 346 | //----------------------------------------------------------------------- |
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[9cc3a18] | 347 | // get index from random number with or without bias towards queues |
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| 348 | static inline [unsigned, bool] idx_from_r(unsigned r, unsigned preferred) { |
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| 349 | unsigned i; |
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| 350 | bool local; |
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| 351 | unsigned rlow = r % BIAS; |
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| 352 | unsigned rhigh = r / BIAS; |
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| 353 | if((0 != rlow) && preferred >= 0) { |
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| 354 | // (BIAS - 1) out of BIAS chances |
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| 355 | // Use perferred queues |
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| 356 | i = preferred + (rhigh % READYQ_SHARD_FACTOR); |
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| 357 | local = true; |
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[b798713] | 358 | } |
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[9cc3a18] | 359 | else { |
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| 360 | // 1 out of BIAS chances |
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| 361 | // Use all queues |
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| 362 | i = rhigh; |
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| 363 | local = false; |
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| 364 | } |
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| 365 | return [i, local]; |
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[13c5e19] | 366 | } |
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| 367 | |
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[9cc3a18] | 368 | //----------------------------------------------------------------------- |
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| 369 | // try to pop from a lane given by index w |
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[13c5e19] | 370 | static inline struct $thread * try_pop(struct cluster * cltr, unsigned w) with (cltr->ready_queue) { |
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[dca5802] | 371 | // Get relevant elements locally |
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| 372 | __intrusive_lane_t & lane = lanes.data[w]; |
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| 373 | |
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[b798713] | 374 | // If list looks empty retry |
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[dca5802] | 375 | if( is_empty(lane) ) return 0p; |
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[b798713] | 376 | |
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| 377 | // If we can't get the lock retry |
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[dca5802] | 378 | if( !__atomic_try_acquire(&lane.lock) ) return 0p; |
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[b798713] | 379 | |
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| 380 | // If list is empty, unlock and retry |
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[dca5802] | 381 | if( is_empty(lane) ) { |
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| 382 | __atomic_unlock(&lane.lock); |
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[b798713] | 383 | return 0p; |
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| 384 | } |
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| 385 | |
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| 386 | // Actually pop the list |
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[504a7dc] | 387 | struct $thread * thrd; |
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[343d10e] | 388 | thrd = pop(lane); |
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[b798713] | 389 | |
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[dca5802] | 390 | /* paranoid */ verify(thrd); |
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| 391 | /* paranoid */ verify(lane.lock); |
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[b798713] | 392 | |
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| 393 | // Unlock and return |
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[dca5802] | 394 | __atomic_unlock(&lane.lock); |
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[b798713] | 395 | |
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[dca5802] | 396 | // Update statistics |
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[b798713] | 397 | #if !defined(__CFA_NO_STATISTICS__) |
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[8834751] | 398 | __tls_stats()->ready.pick.pop.success++; |
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[b798713] | 399 | #endif |
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| 400 | |
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[9cc3a18] | 401 | #if defined(USE_WORKSTEALING) |
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| 402 | lanes.times[i].val = thrd->links.ts; |
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| 403 | #endif |
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[d72c074] | 404 | |
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[dca5802] | 405 | // return the popped thread |
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[b798713] | 406 | return thrd; |
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| 407 | } |
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[04b5cef] | 408 | |
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[9cc3a18] | 409 | //----------------------------------------------------------------------- |
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| 410 | // try to pop from any lanes making sure you don't miss any threads push |
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| 411 | // before the start of the function |
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| 412 | __attribute__((hot)) struct $thread * pop_slow(struct cluster * cltr) with (cltr->ready_queue) { |
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| 413 | /* paranoid */ verify( lanes.count > 0 ); |
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| 414 | unsigned count = __atomic_load_n( &lanes.count, __ATOMIC_RELAXED ); |
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| 415 | unsigned offset = __tls_rand(); |
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| 416 | for(i; count) { |
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| 417 | unsigned idx = (offset + i) % count; |
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| 418 | struct $thread * thrd = try_pop(cltr, idx); |
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| 419 | if(thrd) { |
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| 420 | return thrd; |
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| 421 | } |
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[13c5e19] | 422 | } |
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[9cc3a18] | 423 | |
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| 424 | // All lanes where empty return 0p |
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| 425 | return 0p; |
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[b798713] | 426 | } |
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| 427 | |
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| 428 | //----------------------------------------------------------------------- |
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[9cc3a18] | 429 | // Check that all the intrusive queues in the data structure are still consistent |
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[b798713] | 430 | static void check( __ready_queue_t & q ) with (q) { |
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[7a2972b9] | 431 | #if defined(__CFA_WITH_VERIFY__) && !defined(USE_MPSC) |
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[b798713] | 432 | { |
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[dca5802] | 433 | for( idx ; lanes.count ) { |
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| 434 | __intrusive_lane_t & sl = lanes.data[idx]; |
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| 435 | assert(!lanes.data[idx].lock); |
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[b798713] | 436 | |
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| 437 | assert(head(sl)->link.prev == 0p ); |
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| 438 | assert(head(sl)->link.next->link.prev == head(sl) ); |
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| 439 | assert(tail(sl)->link.next == 0p ); |
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| 440 | assert(tail(sl)->link.prev->link.next == tail(sl) ); |
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| 441 | |
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[7a2972b9] | 442 | if(is_empty(sl)) { |
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[b798713] | 443 | assert(tail(sl)->link.prev == head(sl)); |
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| 444 | assert(head(sl)->link.next == tail(sl)); |
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[1b143de] | 445 | } else { |
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| 446 | assert(tail(sl)->link.prev != head(sl)); |
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| 447 | assert(head(sl)->link.next != tail(sl)); |
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[b798713] | 448 | } |
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| 449 | } |
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| 450 | } |
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| 451 | #endif |
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| 452 | } |
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| 453 | |
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[9cc3a18] | 454 | //----------------------------------------------------------------------- |
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| 455 | // Given 2 indexes, pick the list with the oldest push an try to pop from it |
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| 456 | static inline struct $thread * try_pop(struct cluster * cltr, unsigned i, unsigned j) with (cltr->ready_queue) { |
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| 457 | #if !defined(__CFA_NO_STATISTICS__) |
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| 458 | __tls_stats()->ready.pick.pop.attempt++; |
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| 459 | #endif |
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| 460 | |
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| 461 | // Pick the bet list |
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| 462 | int w = i; |
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| 463 | if( __builtin_expect(!is_empty(lanes.data[j]), true) ) { |
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| 464 | w = (ts(lanes.data[i]) < ts(lanes.data[j])) ? i : j; |
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| 465 | } |
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| 466 | |
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| 467 | return try_pop(cltr, w); |
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| 468 | } |
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| 469 | |
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[b798713] | 470 | // Call this function of the intrusive list was moved using memcpy |
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[dca5802] | 471 | // fixes the list so that the pointers back to anchors aren't left dangling |
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| 472 | static inline void fix(__intrusive_lane_t & ll) { |
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[7a2972b9] | 473 | #if !defined(USE_MPSC) |
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| 474 | // if the list is not empty then follow he pointer and fix its reverse |
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| 475 | if(!is_empty(ll)) { |
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| 476 | head(ll)->link.next->link.prev = head(ll); |
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| 477 | tail(ll)->link.prev->link.next = tail(ll); |
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| 478 | } |
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| 479 | // Otherwise just reset the list |
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| 480 | else { |
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| 481 | verify(tail(ll)->link.next == 0p); |
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| 482 | tail(ll)->link.prev = head(ll); |
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| 483 | head(ll)->link.next = tail(ll); |
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| 484 | verify(head(ll)->link.prev == 0p); |
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| 485 | } |
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| 486 | #endif |
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[b798713] | 487 | } |
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| 488 | |
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[9cc3a18] | 489 | static void assign_list(unsigned & value, dlist(processor, processor) & list, unsigned count) { |
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[a017ee7] | 490 | processor * it = &list`first; |
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| 491 | for(unsigned i = 0; i < count; i++) { |
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| 492 | /* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count); |
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| 493 | it->cltr_id = value; |
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[9cc3a18] | 494 | value += READYQ_SHARD_FACTOR; |
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[a017ee7] | 495 | it = &(*it)`next; |
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| 496 | } |
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| 497 | } |
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| 498 | |
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[9cc3a18] | 499 | static void reassign_cltr_id(struct cluster * cltr) { |
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[a017ee7] | 500 | unsigned preferred = 0; |
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[9cc3a18] | 501 | assign_list(preferred, cltr->procs.actives, cltr->procs.total - cltr->procs.idle); |
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| 502 | assign_list(preferred, cltr->procs.idles , cltr->procs.idle ); |
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[a017ee7] | 503 | } |
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| 504 | |
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[dca5802] | 505 | // Grow the ready queue |
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[a017ee7] | 506 | void ready_queue_grow(struct cluster * cltr) { |
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[bd0bdd37] | 507 | size_t ncount; |
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[a017ee7] | 508 | int target = cltr->procs.total; |
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[bd0bdd37] | 509 | |
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[64a7146] | 510 | /* paranoid */ verify( ready_mutate_islocked() ); |
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[504a7dc] | 511 | __cfadbg_print_safe(ready_queue, "Kernel : Growing ready queue\n"); |
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[b798713] | 512 | |
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[dca5802] | 513 | // Make sure that everything is consistent |
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| 514 | /* paranoid */ check( cltr->ready_queue ); |
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| 515 | |
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| 516 | // grow the ready queue |
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[b798713] | 517 | with( cltr->ready_queue ) { |
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[39fc03e] | 518 | // Find new count |
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| 519 | // Make sure we always have atleast 1 list |
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[bd0bdd37] | 520 | if(target >= 2) { |
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[9cc3a18] | 521 | ncount = target * READYQ_SHARD_FACTOR; |
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[bd0bdd37] | 522 | } else { |
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| 523 | ncount = 1; |
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| 524 | } |
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[b798713] | 525 | |
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[dca5802] | 526 | // Allocate new array (uses realloc and memcpies the data) |
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[ceb7db8] | 527 | lanes.data = alloc( ncount, lanes.data`realloc ); |
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[b798713] | 528 | |
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| 529 | // Fix the moved data |
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[dca5802] | 530 | for( idx; (size_t)lanes.count ) { |
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| 531 | fix(lanes.data[idx]); |
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[b798713] | 532 | } |
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| 533 | |
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| 534 | // Construct new data |
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[dca5802] | 535 | for( idx; (size_t)lanes.count ~ ncount) { |
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| 536 | (lanes.data[idx]){}; |
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[b798713] | 537 | } |
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| 538 | |
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| 539 | // Update original |
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[dca5802] | 540 | lanes.count = ncount; |
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[b798713] | 541 | } |
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| 542 | |
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[9cc3a18] | 543 | fix_times(cltr); |
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| 544 | |
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| 545 | reassign_cltr_id(cltr); |
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[a017ee7] | 546 | |
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[b798713] | 547 | // Make sure that everything is consistent |
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[dca5802] | 548 | /* paranoid */ check( cltr->ready_queue ); |
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| 549 | |
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[504a7dc] | 550 | __cfadbg_print_safe(ready_queue, "Kernel : Growing ready queue done\n"); |
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[dca5802] | 551 | |
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[64a7146] | 552 | /* paranoid */ verify( ready_mutate_islocked() ); |
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[b798713] | 553 | } |
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| 554 | |
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[dca5802] | 555 | // Shrink the ready queue |
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[a017ee7] | 556 | void ready_queue_shrink(struct cluster * cltr) { |
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[64a7146] | 557 | /* paranoid */ verify( ready_mutate_islocked() ); |
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[504a7dc] | 558 | __cfadbg_print_safe(ready_queue, "Kernel : Shrinking ready queue\n"); |
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[dca5802] | 559 | |
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| 560 | // Make sure that everything is consistent |
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| 561 | /* paranoid */ check( cltr->ready_queue ); |
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| 562 | |
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[a017ee7] | 563 | int target = cltr->procs.total; |
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| 564 | |
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[b798713] | 565 | with( cltr->ready_queue ) { |
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[39fc03e] | 566 | // Remember old count |
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[dca5802] | 567 | size_t ocount = lanes.count; |
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[b798713] | 568 | |
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[39fc03e] | 569 | // Find new count |
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| 570 | // Make sure we always have atleast 1 list |
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[9cc3a18] | 571 | lanes.count = target >= 2 ? target * READYQ_SHARD_FACTOR: 1; |
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[39fc03e] | 572 | /* paranoid */ verify( ocount >= lanes.count ); |
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[9cc3a18] | 573 | /* paranoid */ verify( lanes.count == target * READYQ_SHARD_FACTOR || target < 2 ); |
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[dca5802] | 574 | |
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| 575 | // for printing count the number of displaced threads |
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[504a7dc] | 576 | #if defined(__CFA_DEBUG_PRINT__) || defined(__CFA_DEBUG_PRINT_READY_QUEUE__) |
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[dca5802] | 577 | __attribute__((unused)) size_t displaced = 0; |
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| 578 | #endif |
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[b798713] | 579 | |
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| 580 | // redistribute old data |
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[dca5802] | 581 | for( idx; (size_t)lanes.count ~ ocount) { |
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| 582 | // Lock is not strictly needed but makes checking invariants much easier |
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[1b143de] | 583 | __attribute__((unused)) bool locked = __atomic_try_acquire(&lanes.data[idx].lock); |
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[b798713] | 584 | verify(locked); |
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[dca5802] | 585 | |
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| 586 | // As long as we can pop from this lane to push the threads somewhere else in the queue |
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| 587 | while(!is_empty(lanes.data[idx])) { |
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[504a7dc] | 588 | struct $thread * thrd; |
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[343d10e] | 589 | thrd = pop(lanes.data[idx]); |
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[dca5802] | 590 | |
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[b798713] | 591 | push(cltr, thrd); |
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[dca5802] | 592 | |
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| 593 | // for printing count the number of displaced threads |
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[504a7dc] | 594 | #if defined(__CFA_DEBUG_PRINT__) || defined(__CFA_DEBUG_PRINT_READY_QUEUE__) |
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[dca5802] | 595 | displaced++; |
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| 596 | #endif |
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[b798713] | 597 | } |
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| 598 | |
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[dca5802] | 599 | // Unlock the lane |
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| 600 | __atomic_unlock(&lanes.data[idx].lock); |
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[b798713] | 601 | |
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| 602 | // TODO print the queue statistics here |
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| 603 | |
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[dca5802] | 604 | ^(lanes.data[idx]){}; |
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[b798713] | 605 | } |
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| 606 | |
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[504a7dc] | 607 | __cfadbg_print_safe(ready_queue, "Kernel : Shrinking ready queue displaced %zu threads\n", displaced); |
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[c84b4be] | 608 | |
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[dca5802] | 609 | // Allocate new array (uses realloc and memcpies the data) |
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[ceb7db8] | 610 | lanes.data = alloc( lanes.count, lanes.data`realloc ); |
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[b798713] | 611 | |
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| 612 | // Fix the moved data |
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[dca5802] | 613 | for( idx; (size_t)lanes.count ) { |
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| 614 | fix(lanes.data[idx]); |
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[b798713] | 615 | } |
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| 616 | } |
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| 617 | |
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[9cc3a18] | 618 | fix_times(cltr); |
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| 619 | |
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| 620 | reassign_cltr_id(cltr); |
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[a017ee7] | 621 | |
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[b798713] | 622 | // Make sure that everything is consistent |
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[dca5802] | 623 | /* paranoid */ check( cltr->ready_queue ); |
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| 624 | |
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[504a7dc] | 625 | __cfadbg_print_safe(ready_queue, "Kernel : Shrinking ready queue done\n"); |
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[64a7146] | 626 | /* paranoid */ verify( ready_mutate_islocked() ); |
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[fd9b524] | 627 | } |
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