[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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[9b1dcc2] | 27 |
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[1c273d0] | 28 | extern "C" {
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[2026bb6] | 29 | void disable_interrupts() OPTIONAL_THREAD;
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[a3821fa] | 30 | void enable_interrupts( bool poll = true );
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[1c273d0] | 31 | }
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| 32 |
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[254ad1b] | 33 | void schedule_thread$( $thread * ) __attribute__((nonnull (1)));
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[75f3522] | 34 |
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[8fc652e0] | 35 | extern bool __preemption_enabled();
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| 36 |
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[5afb49a] | 37 | //release/wake-up the following resources
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| 38 | void __thread_finish( $thread * thrd );
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[db6f06a] | 39 |
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[75f3522] | 40 | //-----------------------------------------------------------------------------
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| 41 | // Processor
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| 42 | void main(processorCtx_t *);
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[85b1deb] | 43 |
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[8c50aed] | 44 | void * __create_pthread( pthread_t *, void * (*)(void *), void * );
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[bfcf6b9] | 45 | void __destroy_pthread( pthread_t pthread, void * stack, void ** retval );
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[1805b1b] | 46 |
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[85b1deb] | 47 |
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[75f3522] | 48 |
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[6502a2b] | 49 | extern cluster * mainCluster;
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| 50 |
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[75f3522] | 51 | //-----------------------------------------------------------------------------
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| 52 | // Threads
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| 53 | extern "C" {
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[c7a900a] | 54 | void __cfactx_invoke_thread(void (*main)(void *), void * this);
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[75f3522] | 55 | }
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| 56 |
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[f7d6bb0] | 57 | __cfaabi_dbg_debug_do(
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[ac2b598] | 58 | extern void __cfaabi_dbg_thread_register ( $thread * thrd );
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| 59 | extern void __cfaabi_dbg_thread_unregister( $thread * thrd );
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[f7d6bb0] | 60 | )
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| 61 |
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[6a77224] | 62 | #define TICKET_BLOCKED (-1) // thread is blocked
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| 63 | #define TICKET_RUNNING ( 0) // thread is running
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| 64 | #define TICKET_UNBLOCK ( 1) // thread should ignore next block
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| 65 |
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[969b3fe] | 66 | //-----------------------------------------------------------------------------
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| 67 | // Utils
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[ac2b598] | 68 | void doregister( struct cluster * cltr, struct $thread & thrd );
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| 69 | void unregister( struct cluster * cltr, struct $thread & thrd );
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[de94a60] | 70 |
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[f00b26d4] | 71 | //-----------------------------------------------------------------------------
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| 72 | // I/O
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[78da4ab] | 73 | $io_arbiter * create(void);
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| 74 | void destroy($io_arbiter *);
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[f00b26d4] | 75 |
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[7768b8d] | 76 | //=======================================================================
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| 77 | // Cluster lock API
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| 78 | //=======================================================================
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| 79 | // Lock-Free registering/unregistering of threads
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| 80 | // Register a processor to a given cluster and get its unique id in return
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[c993b15] | 81 | unsigned register_proc_id( void );
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[7768b8d] | 82 |
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| 83 | // Unregister a processor from a given cluster using its id, getting back the original pointer
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[c993b15] | 84 | void unregister_proc_id( unsigned );
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[7768b8d] | 85 |
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| 86 | //=======================================================================
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| 87 | // Reader-writer lock implementation
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| 88 | // Concurrent with doregister/unregister,
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| 89 | // i.e., threads can be added at any point during or between the entry/exit
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[dca5802] | 90 |
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| 91 | //-----------------------------------------------------------------------
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| 92 | // simple spinlock underlying the RWLock
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| 93 | // Blocking acquire
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[7768b8d] | 94 | static inline void __atomic_acquire(volatile bool * ll) {
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| 95 | while( __builtin_expect(__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST), false) ) {
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| 96 | while(__atomic_load_n(ll, (int)__ATOMIC_RELAXED))
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[fd9b524] | 97 | Pause();
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[7768b8d] | 98 | }
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| 99 | /* paranoid */ verify(*ll);
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| 100 | }
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| 101 |
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[dca5802] | 102 | // Non-Blocking acquire
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[7768b8d] | 103 | static inline bool __atomic_try_acquire(volatile bool * ll) {
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[b798713] | 104 | return !__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST);
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[7768b8d] | 105 | }
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| 106 |
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[dca5802] | 107 | // Release
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[7768b8d] | 108 | static inline void __atomic_unlock(volatile bool * ll) {
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| 109 | /* paranoid */ verify(*ll);
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| 110 | __atomic_store_n(ll, (bool)false, __ATOMIC_RELEASE);
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| 111 | }
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| 112 |
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[a33c113] | 113 |
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| 114 |
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| 115 |
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| 116 |
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[b388ee81] | 117 | //-----------------------------------------------------------------------
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| 118 | // Reader-Writer lock protecting the ready-queues
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| 119 | // while this lock is mostly generic some aspects
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| 120 | // have been hard-coded to for the ready-queue for
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| 121 | // simplicity and performance
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| 122 | struct __scheduler_RWLock_t {
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| 123 | // total cachelines allocated
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| 124 | unsigned int max;
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| 125 |
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| 126 | // cachelines currently in use
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| 127 | volatile unsigned int alloc;
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| 128 |
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| 129 | // cachelines ready to itereate over
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| 130 | // (!= to alloc when thread is in second half of doregister)
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| 131 | volatile unsigned int ready;
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| 132 |
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| 133 | // writer lock
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[c993b15] | 134 | volatile bool write_lock;
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[b388ee81] | 135 |
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| 136 | // data pointer
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[c993b15] | 137 | volatile bool * volatile * data;
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[b388ee81] | 138 | };
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| 139 |
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| 140 | void ?{}(__scheduler_RWLock_t & this);
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| 141 | void ^?{}(__scheduler_RWLock_t & this);
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| 142 |
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| 143 | extern __scheduler_RWLock_t * __scheduler_lock;
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| 144 |
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[7768b8d] | 145 | //-----------------------------------------------------------------------
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| 146 | // Reader side : acquire when using the ready queue to schedule but not
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| 147 | // creating/destroying queues
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[e873838] | 148 | static inline void ready_schedule_lock(void) with(*__scheduler_lock) {
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[8fc652e0] | 149 | /* paranoid */ verify( ! __preemption_enabled() );
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[c993b15] | 150 | /* paranoid */ verify( ! kernelTLS().in_sched_lock );
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| 151 | /* paranoid */ verify( data[kernelTLS().sched_id] == &kernelTLS().sched_lock );
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| 152 | /* paranoid */ verify( !kernelTLS().this_processor || kernelTLS().this_processor->unique_id == kernelTLS().sched_id );
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[7768b8d] | 153 |
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| 154 | // Step 1 : make sure no writer are in the middle of the critical section
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[c993b15] | 155 | while(__atomic_load_n(&write_lock, (int)__ATOMIC_RELAXED))
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[fd9b524] | 156 | Pause();
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[7768b8d] | 157 |
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| 158 | // Fence needed because we don't want to start trying to acquire the lock
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| 159 | // before we read a false.
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| 160 | // Not needed on x86
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| 161 | // std::atomic_thread_fence(std::memory_order_seq_cst);
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| 162 |
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| 163 | // Step 2 : acquire our local lock
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[c993b15] | 164 | __atomic_acquire( &kernelTLS().sched_lock );
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| 165 | /*paranoid*/ verify(kernelTLS().sched_lock);
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[64a7146] | 166 |
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| 167 | #ifdef __CFA_WITH_VERIFY__
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| 168 | // Debug, check if this is owned for reading
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[c993b15] | 169 | kernelTLS().in_sched_lock = true;
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[64a7146] | 170 | #endif
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[7768b8d] | 171 | }
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| 172 |
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[e873838] | 173 | static inline void ready_schedule_unlock(void) with(*__scheduler_lock) {
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[8fc652e0] | 174 | /* paranoid */ verify( ! __preemption_enabled() );
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[c993b15] | 175 | /* paranoid */ verify( data[kernelTLS().sched_id] == &kernelTLS().sched_lock );
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| 176 | /* paranoid */ verify( !kernelTLS().this_processor || kernelTLS().this_processor->unique_id == kernelTLS().sched_id );
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| 177 | /* paranoid */ verify( kernelTLS().sched_lock );
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| 178 | /* paranoid */ verify( kernelTLS().in_sched_lock );
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[64a7146] | 179 | #ifdef __CFA_WITH_VERIFY__
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| 180 | // Debug, check if this is owned for reading
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[c993b15] | 181 | kernelTLS().in_sched_lock = false;
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[64a7146] | 182 | #endif
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[c993b15] | 183 | __atomic_unlock(&kernelTLS().sched_lock);
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[7768b8d] | 184 | }
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| 185 |
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[64a7146] | 186 | #ifdef __CFA_WITH_VERIFY__
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[e873838] | 187 | static inline bool ready_schedule_islocked(void) {
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[8fc652e0] | 188 | /* paranoid */ verify( ! __preemption_enabled() );
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[c993b15] | 189 | /* paranoid */ verify( (!kernelTLS().in_sched_lock) || kernelTLS().sched_lock );
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| 190 | return kernelTLS().sched_lock;
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[64a7146] | 191 | }
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| 192 |
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| 193 | static inline bool ready_mutate_islocked() {
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[c993b15] | 194 | return __scheduler_lock->write_lock;
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[64a7146] | 195 | }
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| 196 | #endif
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| 197 |
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[7768b8d] | 198 | //-----------------------------------------------------------------------
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| 199 | // Writer side : acquire when changing the ready queue, e.g. adding more
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| 200 | // queues or removing them.
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[b388ee81] | 201 | uint_fast32_t ready_mutate_lock( void );
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[7768b8d] | 202 |
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[b388ee81] | 203 | void ready_mutate_unlock( uint_fast32_t /* value returned by lock */ );
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[7768b8d] | 204 |
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[a33c113] | 205 | //-----------------------------------------------------------------------
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| 206 | // Lock-Free registering/unregistering of threads
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| 207 | // Register a processor to a given cluster and get its unique id in return
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| 208 | // For convenience, also acquires the lock
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[c993b15] | 209 | static inline [unsigned, uint_fast32_t] ready_mutate_register() {
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| 210 | unsigned id = register_proc_id();
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| 211 | uint_fast32_t last = ready_mutate_lock();
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| 212 | return [id, last];
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[a33c113] | 213 | }
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| 214 |
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| 215 | // Unregister a processor from a given cluster using its id, getting back the original pointer
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| 216 | // assumes the lock is acquired
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[c993b15] | 217 | static inline void ready_mutate_unregister( unsigned id, uint_fast32_t last_s ) {
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[a33c113] | 218 | ready_mutate_unlock( last_s );
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[c993b15] | 219 | unregister_proc_id( id );
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[a33c113] | 220 | }
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| 221 |
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[a7504db5] | 222 | //-----------------------------------------------------------------------
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| 223 | // Cluster idle lock/unlock
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[6a9b12b] | 224 | static inline void lock(__cluster_proc_list & this) {
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[a7504db5] | 225 | /* paranoid */ verify( ! __preemption_enabled() );
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| 226 |
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| 227 | // Start by locking the global RWlock so that we know no-one is
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| 228 | // adding/removing processors while we mess with the idle lock
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| 229 | ready_schedule_lock();
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| 230 |
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| 231 | // Simple counting lock, acquired, acquired by incrementing the counter
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| 232 | // to an odd number
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| 233 | for() {
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| 234 | uint64_t l = this.lock;
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| 235 | if(
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| 236 | (0 == (l % 2))
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| 237 | && __atomic_compare_exchange_n(&this.lock, &l, l + 1, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
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| 238 | ) return;
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| 239 | Pause();
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| 240 | }
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| 241 |
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| 242 | /* paranoid */ verify( ! __preemption_enabled() );
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| 243 | }
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| 244 |
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[6a9b12b] | 245 | static inline void unlock(__cluster_proc_list & this) {
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[a7504db5] | 246 | /* paranoid */ verify( ! __preemption_enabled() );
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| 247 |
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| 248 | /* paranoid */ verify( 1 == (this.lock % 2) );
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| 249 | // Simple couting lock, release by incrementing to an even number
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| 250 | __atomic_fetch_add( &this.lock, 1, __ATOMIC_SEQ_CST );
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| 251 |
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| 252 | // Release the global lock, which we acquired when locking
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| 253 | ready_schedule_unlock();
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| 254 |
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| 255 | /* paranoid */ verify( ! __preemption_enabled() );
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| 256 | }
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| 257 |
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[b798713] | 258 | //=======================================================================
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| 259 | // Ready-Queue API
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[dca5802] | 260 | //-----------------------------------------------------------------------
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| 261 | // push thread onto a ready queue for a cluster
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| 262 | // returns true if the list was previously empty, false otherwise
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[9cc3a18] | 263 | __attribute__((hot)) void push(struct cluster * cltr, struct $thread * thrd);
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[dca5802] | 264 |
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| 265 | //-----------------------------------------------------------------------
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[fc59df78] | 266 | // pop thread from the local queues of a cluster
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[dca5802] | 267 | // returns 0p if empty
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[1eb239e4] | 268 | // May return 0p spuriously
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[431cd4f] | 269 | __attribute__((hot)) struct $thread * pop_fast(struct cluster * cltr);
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[dca5802] | 270 |
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[1eb239e4] | 271 | //-----------------------------------------------------------------------
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[fc59df78] | 272 | // pop thread from any ready queue of a cluster
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[1eb239e4] | 273 | // returns 0p if empty
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[fc59df78] | 274 | // May return 0p spuriously
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[1eb239e4] | 275 | __attribute__((hot)) struct $thread * pop_slow(struct cluster * cltr);
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| 276 |
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[fc59df78] | 277 | //-----------------------------------------------------------------------
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| 278 | // search all ready queues of a cluster for any thread
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| 279 | // returns 0p if empty
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| 280 | // guaranteed to find any threads added before this call
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| 281 | __attribute__((hot)) struct $thread * pop_search(struct cluster * cltr);
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| 282 |
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[dca5802] | 283 | //-----------------------------------------------------------------------
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| 284 | // Increase the width of the ready queue (number of lanes) by 4
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[a017ee7] | 285 | void ready_queue_grow (struct cluster * cltr);
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[dca5802] | 286 |
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| 287 | //-----------------------------------------------------------------------
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| 288 | // Decrease the width of the ready queue (number of lanes) by 4
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[a017ee7] | 289 | void ready_queue_shrink(struct cluster * cltr);
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[b798713] | 290 |
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[de94a60] | 291 |
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[75f3522] | 292 | // Local Variables: //
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| 293 | // mode: c //
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| 294 | // tab-width: 4 //
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[4aa2fb2] | 295 | // End: //
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