[75f3522] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2016 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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[73abe95] | 7 | // kernel_private.hfa -- |
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[75f3522] | 8 | // |
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| 9 | // Author : Thierry Delisle |
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| 10 | // Created On : Mon Feb 13 12:27:26 2017 |
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[6b0b624] | 11 | // Last Modified By : Peter A. Buhr |
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[fd9b524] | 12 | // Last Modified On : Wed Aug 12 08:21:33 2020 |
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| 13 | // Update Count : 9 |
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[75f3522] | 14 | // |
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| 15 | |
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[6b0b624] | 16 | #pragma once |
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[75f3522] | 17 | |
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[58b6d1b] | 18 | #include "kernel.hfa" |
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| 19 | #include "thread.hfa" |
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[75f3522] | 20 | |
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[73abe95] | 21 | #include "alarm.hfa" |
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[8834751] | 22 | #include "stats.hfa" |
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[fa21ac9] | 23 | |
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[75f3522] | 24 | //----------------------------------------------------------------------------- |
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| 25 | // Scheduler |
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[1c273d0] | 26 | |
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[37ba662] | 27 | struct __attribute__((aligned(128))) __scheduler_lock_id_t; |
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[9b1dcc2] | 28 | |
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[1c273d0] | 29 | extern "C" { |
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[2026bb6] | 30 | void disable_interrupts() OPTIONAL_THREAD; |
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[969b3fe] | 31 | void enable_interrupts_noPoll(); |
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[36982fc] | 32 | void enable_interrupts( __cfaabi_dbg_ctx_param ); |
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[1c273d0] | 33 | } |
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| 34 | |
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[e873838] | 35 | void __schedule_thread( $thread * ) |
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[efc171d1] | 36 | #if defined(NDEBUG) || (!defined(__CFA_DEBUG__) && !defined(__CFA_VERIFY__)) |
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[e873838] | 37 | __attribute__((nonnull (1))) |
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[efc171d1] | 38 | #endif |
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| 39 | ; |
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[75f3522] | 40 | |
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[8fc652e0] | 41 | extern bool __preemption_enabled(); |
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| 42 | |
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[5afb49a] | 43 | //release/wake-up the following resources |
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| 44 | void __thread_finish( $thread * thrd ); |
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[db6f06a] | 45 | |
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[75f3522] | 46 | //----------------------------------------------------------------------------- |
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| 47 | // Processor |
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| 48 | void main(processorCtx_t *); |
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[85b1deb] | 49 | |
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[8c50aed] | 50 | void * __create_pthread( pthread_t *, void * (*)(void *), void * ); |
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[bfcf6b9] | 51 | void __destroy_pthread( pthread_t pthread, void * stack, void ** retval ); |
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[1805b1b] | 52 | |
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[85b1deb] | 53 | |
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[75f3522] | 54 | |
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[6502a2b] | 55 | extern cluster * mainCluster; |
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| 56 | |
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[75f3522] | 57 | //----------------------------------------------------------------------------- |
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| 58 | // Threads |
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| 59 | extern "C" { |
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[c7a900a] | 60 | void __cfactx_invoke_thread(void (*main)(void *), void * this); |
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[75f3522] | 61 | } |
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| 62 | |
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[f7d6bb0] | 63 | __cfaabi_dbg_debug_do( |
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[ac2b598] | 64 | extern void __cfaabi_dbg_thread_register ( $thread * thrd ); |
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| 65 | extern void __cfaabi_dbg_thread_unregister( $thread * thrd ); |
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[f7d6bb0] | 66 | ) |
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| 67 | |
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[6a77224] | 68 | #define TICKET_BLOCKED (-1) // thread is blocked |
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| 69 | #define TICKET_RUNNING ( 0) // thread is running |
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| 70 | #define TICKET_UNBLOCK ( 1) // thread should ignore next block |
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| 71 | |
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[969b3fe] | 72 | //----------------------------------------------------------------------------- |
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| 73 | // Utils |
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[ac2b598] | 74 | void doregister( struct cluster * cltr, struct $thread & thrd ); |
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| 75 | void unregister( struct cluster * cltr, struct $thread & thrd ); |
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[de94a60] | 76 | |
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[f00b26d4] | 77 | //----------------------------------------------------------------------------- |
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| 78 | // I/O |
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[78da4ab] | 79 | $io_arbiter * create(void); |
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| 80 | void destroy($io_arbiter *); |
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[f00b26d4] | 81 | |
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[7768b8d] | 82 | //======================================================================= |
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| 83 | // Cluster lock API |
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| 84 | //======================================================================= |
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| 85 | // Lock-Free registering/unregistering of threads |
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| 86 | // Register a processor to a given cluster and get its unique id in return |
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[a33c113] | 87 | void register_proc_id( struct __processor_id_t * ); |
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[7768b8d] | 88 | |
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| 89 | // Unregister a processor from a given cluster using its id, getting back the original pointer |
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[a33c113] | 90 | void unregister_proc_id( struct __processor_id_t * proc ); |
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[7768b8d] | 91 | |
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| 92 | //======================================================================= |
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| 93 | // Reader-writer lock implementation |
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| 94 | // Concurrent with doregister/unregister, |
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| 95 | // i.e., threads can be added at any point during or between the entry/exit |
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[dca5802] | 96 | |
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| 97 | //----------------------------------------------------------------------- |
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| 98 | // simple spinlock underlying the RWLock |
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| 99 | // Blocking acquire |
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[7768b8d] | 100 | static inline void __atomic_acquire(volatile bool * ll) { |
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| 101 | while( __builtin_expect(__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST), false) ) { |
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| 102 | while(__atomic_load_n(ll, (int)__ATOMIC_RELAXED)) |
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[fd9b524] | 103 | Pause(); |
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[7768b8d] | 104 | } |
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| 105 | /* paranoid */ verify(*ll); |
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| 106 | } |
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| 107 | |
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[dca5802] | 108 | // Non-Blocking acquire |
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[7768b8d] | 109 | static inline bool __atomic_try_acquire(volatile bool * ll) { |
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[b798713] | 110 | return !__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST); |
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[7768b8d] | 111 | } |
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| 112 | |
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[dca5802] | 113 | // Release |
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[7768b8d] | 114 | static inline void __atomic_unlock(volatile bool * ll) { |
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| 115 | /* paranoid */ verify(*ll); |
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| 116 | __atomic_store_n(ll, (bool)false, __ATOMIC_RELEASE); |
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| 117 | } |
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| 118 | |
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[a33c113] | 119 | // Cells use by the reader writer lock |
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| 120 | // while not generic it only relies on a opaque pointer |
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| 121 | struct __attribute__((aligned(128))) __scheduler_lock_id_t { |
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| 122 | // Spin lock used as the underlying lock |
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| 123 | volatile bool lock; |
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| 124 | |
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| 125 | // Handle pointing to the proc owning this cell |
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| 126 | // Used for allocating cells and debugging |
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| 127 | __processor_id_t * volatile handle; |
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| 128 | |
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| 129 | #ifdef __CFA_WITH_VERIFY__ |
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| 130 | // Debug, check if this is owned for reading |
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| 131 | bool owned; |
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| 132 | #endif |
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| 133 | }; |
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| 134 | |
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| 135 | static_assert( sizeof(struct __scheduler_lock_id_t) <= __alignof(struct __scheduler_lock_id_t)); |
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| 136 | |
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[b388ee81] | 137 | //----------------------------------------------------------------------- |
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| 138 | // Reader-Writer lock protecting the ready-queues |
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| 139 | // while this lock is mostly generic some aspects |
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| 140 | // have been hard-coded to for the ready-queue for |
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| 141 | // simplicity and performance |
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| 142 | struct __scheduler_RWLock_t { |
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| 143 | // total cachelines allocated |
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| 144 | unsigned int max; |
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| 145 | |
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| 146 | // cachelines currently in use |
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| 147 | volatile unsigned int alloc; |
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| 148 | |
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| 149 | // cachelines ready to itereate over |
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| 150 | // (!= to alloc when thread is in second half of doregister) |
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| 151 | volatile unsigned int ready; |
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| 152 | |
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| 153 | // writer lock |
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| 154 | volatile bool lock; |
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| 155 | |
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| 156 | // data pointer |
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[9b1dcc2] | 157 | __scheduler_lock_id_t * data; |
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[b388ee81] | 158 | }; |
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| 159 | |
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| 160 | void ?{}(__scheduler_RWLock_t & this); |
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| 161 | void ^?{}(__scheduler_RWLock_t & this); |
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| 162 | |
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| 163 | extern __scheduler_RWLock_t * __scheduler_lock; |
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| 164 | |
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[7768b8d] | 165 | //----------------------------------------------------------------------- |
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| 166 | // Reader side : acquire when using the ready queue to schedule but not |
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| 167 | // creating/destroying queues |
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[e873838] | 168 | static inline void ready_schedule_lock(void) with(*__scheduler_lock) { |
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[8fc652e0] | 169 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 170 | /* paranoid */ verify( kernelTLS().this_proc_id ); |
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[e873838] | 171 | |
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[8fc652e0] | 172 | unsigned iproc = kernelTLS().this_proc_id->id; |
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| 173 | /*paranoid*/ verify(data[iproc].handle == kernelTLS().this_proc_id); |
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[7768b8d] | 174 | /*paranoid*/ verify(iproc < ready); |
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| 175 | |
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| 176 | // Step 1 : make sure no writer are in the middle of the critical section |
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| 177 | while(__atomic_load_n(&lock, (int)__ATOMIC_RELAXED)) |
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[fd9b524] | 178 | Pause(); |
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[7768b8d] | 179 | |
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| 180 | // Fence needed because we don't want to start trying to acquire the lock |
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| 181 | // before we read a false. |
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| 182 | // Not needed on x86 |
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| 183 | // std::atomic_thread_fence(std::memory_order_seq_cst); |
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| 184 | |
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| 185 | // Step 2 : acquire our local lock |
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| 186 | __atomic_acquire( &data[iproc].lock ); |
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| 187 | /*paranoid*/ verify(data[iproc].lock); |
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[64a7146] | 188 | |
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| 189 | #ifdef __CFA_WITH_VERIFY__ |
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| 190 | // Debug, check if this is owned for reading |
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| 191 | data[iproc].owned = true; |
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| 192 | #endif |
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[7768b8d] | 193 | } |
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| 194 | |
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[e873838] | 195 | static inline void ready_schedule_unlock(void) with(*__scheduler_lock) { |
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[8fc652e0] | 196 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 197 | /* paranoid */ verify( kernelTLS().this_proc_id ); |
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[e873838] | 198 | |
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[8fc652e0] | 199 | unsigned iproc = kernelTLS().this_proc_id->id; |
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| 200 | /*paranoid*/ verify(data[iproc].handle == kernelTLS().this_proc_id); |
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[7768b8d] | 201 | /*paranoid*/ verify(iproc < ready); |
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| 202 | /*paranoid*/ verify(data[iproc].lock); |
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[64a7146] | 203 | /*paranoid*/ verify(data[iproc].owned); |
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| 204 | #ifdef __CFA_WITH_VERIFY__ |
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| 205 | // Debug, check if this is owned for reading |
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| 206 | data[iproc].owned = false; |
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| 207 | #endif |
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[dca5802] | 208 | __atomic_unlock(&data[iproc].lock); |
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[7768b8d] | 209 | } |
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| 210 | |
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[64a7146] | 211 | #ifdef __CFA_WITH_VERIFY__ |
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[e873838] | 212 | static inline bool ready_schedule_islocked(void) { |
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[8fc652e0] | 213 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 214 | /*paranoid*/ verify( kernelTLS().this_proc_id ); |
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| 215 | __processor_id_t * proc = kernelTLS().this_proc_id; |
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[64a7146] | 216 | return __scheduler_lock->data[proc->id].owned; |
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| 217 | } |
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| 218 | |
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| 219 | static inline bool ready_mutate_islocked() { |
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| 220 | return __scheduler_lock->lock; |
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| 221 | } |
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| 222 | #endif |
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| 223 | |
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[7768b8d] | 224 | //----------------------------------------------------------------------- |
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| 225 | // Writer side : acquire when changing the ready queue, e.g. adding more |
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| 226 | // queues or removing them. |
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[b388ee81] | 227 | uint_fast32_t ready_mutate_lock( void ); |
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[7768b8d] | 228 | |
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[b388ee81] | 229 | void ready_mutate_unlock( uint_fast32_t /* value returned by lock */ ); |
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[7768b8d] | 230 | |
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[a33c113] | 231 | //----------------------------------------------------------------------- |
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| 232 | // Lock-Free registering/unregistering of threads |
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| 233 | // Register a processor to a given cluster and get its unique id in return |
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| 234 | // For convenience, also acquires the lock |
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| 235 | static inline uint_fast32_t ready_mutate_register( struct __processor_id_t * proc ) { |
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| 236 | register_proc_id( proc ); |
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| 237 | return ready_mutate_lock(); |
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| 238 | } |
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| 239 | |
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| 240 | // Unregister a processor from a given cluster using its id, getting back the original pointer |
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| 241 | // assumes the lock is acquired |
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| 242 | static inline void ready_mutate_unregister( struct __processor_id_t * proc, uint_fast32_t last_s ) { |
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| 243 | ready_mutate_unlock( last_s ); |
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| 244 | unregister_proc_id( proc ); |
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| 245 | } |
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| 246 | |
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[a7504db] | 247 | //----------------------------------------------------------------------- |
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| 248 | // Cluster idle lock/unlock |
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[6a9b12b] | 249 | static inline void lock(__cluster_proc_list & this) { |
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[a7504db] | 250 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 251 | |
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| 252 | // Start by locking the global RWlock so that we know no-one is |
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| 253 | // adding/removing processors while we mess with the idle lock |
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| 254 | ready_schedule_lock(); |
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| 255 | |
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| 256 | // Simple counting lock, acquired, acquired by incrementing the counter |
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| 257 | // to an odd number |
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| 258 | for() { |
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| 259 | uint64_t l = this.lock; |
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| 260 | if( |
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| 261 | (0 == (l % 2)) |
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| 262 | && __atomic_compare_exchange_n(&this.lock, &l, l + 1, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) |
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| 263 | ) return; |
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| 264 | Pause(); |
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| 265 | } |
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| 266 | |
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| 267 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 268 | } |
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| 269 | |
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[6a9b12b] | 270 | static inline void unlock(__cluster_proc_list & this) { |
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[a7504db] | 271 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 272 | |
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| 273 | /* paranoid */ verify( 1 == (this.lock % 2) ); |
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| 274 | // Simple couting lock, release by incrementing to an even number |
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| 275 | __atomic_fetch_add( &this.lock, 1, __ATOMIC_SEQ_CST ); |
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| 276 | |
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| 277 | // Release the global lock, which we acquired when locking |
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| 278 | ready_schedule_unlock(); |
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| 279 | |
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| 280 | /* paranoid */ verify( ! __preemption_enabled() ); |
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| 281 | } |
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| 282 | |
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[b798713] | 283 | //======================================================================= |
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| 284 | // Ready-Queue API |
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[dca5802] | 285 | //----------------------------------------------------------------------- |
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| 286 | // push thread onto a ready queue for a cluster |
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| 287 | // returns true if the list was previously empty, false otherwise |
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[9cc3a18] | 288 | __attribute__((hot)) void push(struct cluster * cltr, struct $thread * thrd); |
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[dca5802] | 289 | |
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| 290 | //----------------------------------------------------------------------- |
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| 291 | // pop thread from the ready queue of a cluster |
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| 292 | // returns 0p if empty |
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[1eb239e4] | 293 | // May return 0p spuriously |
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[431cd4f] | 294 | __attribute__((hot)) struct $thread * pop_fast(struct cluster * cltr); |
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[dca5802] | 295 | |
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[1eb239e4] | 296 | //----------------------------------------------------------------------- |
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| 297 | // pop thread from the ready queue of a cluster |
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| 298 | // returns 0p if empty |
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| 299 | // guaranteed to find any threads added before this call |
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| 300 | __attribute__((hot)) struct $thread * pop_slow(struct cluster * cltr); |
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| 301 | |
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[dca5802] | 302 | //----------------------------------------------------------------------- |
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| 303 | // Increase the width of the ready queue (number of lanes) by 4 |
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[a017ee7] | 304 | void ready_queue_grow (struct cluster * cltr); |
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[dca5802] | 305 | |
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| 306 | //----------------------------------------------------------------------- |
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| 307 | // Decrease the width of the ready queue (number of lanes) by 4 |
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[a017ee7] | 308 | void ready_queue_shrink(struct cluster * cltr); |
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[b798713] | 309 | |
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[de94a60] | 310 | |
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[75f3522] | 311 | // Local Variables: // |
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| 312 | // mode: c // |
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| 313 | // tab-width: 4 // |
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[4aa2fb2] | 314 | // End: // |
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