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| author | Mitja Felicijan <mitja.felicijan@gmail.com> | 2026-01-21 22:52:54 +0100 |
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| committer | Mitja Felicijan <mitja.felicijan@gmail.com> | 2026-01-21 22:52:54 +0100 |
| commit | dcacc00e3750300617ba6e16eb346713f91a783a (patch) | |
| tree | 38e2d4fb5ed9d119711d4295c6eda4b014af73fd /examples/redis-unstable/src/atomicvar.h | |
| parent | 58dac10aeb8f5a041c46bddbeaf4c7966a99b998 (diff) | |
| download | crep-dcacc00e3750300617ba6e16eb346713f91a783a.tar.gz | |
Remove testing data
Diffstat (limited to 'examples/redis-unstable/src/atomicvar.h')
| -rw-r--r-- | examples/redis-unstable/src/atomicvar.h | 186 |
1 files changed, 0 insertions, 186 deletions
diff --git a/examples/redis-unstable/src/atomicvar.h b/examples/redis-unstable/src/atomicvar.h deleted file mode 100644 index 3c332ee..0000000 --- a/examples/redis-unstable/src/atomicvar.h +++ /dev/null @@ -1,186 +0,0 @@ -/* This file implements atomic counters using c11 _Atomic, __atomic or __sync - * macros if available, otherwise we will throw an error when compile. - * - * The exported interface is composed of the following macros: - * - * atomicIncr(var,count) -- Increment the atomic counter - * atomicGetIncr(var,oldvalue_var,count) -- Get and increment the atomic counter - * atomicIncrGet(var,newvalue_var,count) -- Increment and get the atomic counter new value - * atomicDecr(var,count) -- Decrement the atomic counter - * atomicGet(var,dstvar) -- Fetch the atomic counter value - * atomicSet(var,value) -- Set the atomic counter value - * atomicGetWithSync(var,value) -- 'atomicGet' with inter-thread synchronization - * atomicSetWithSync(var,value) -- 'atomicSet' with inter-thread synchronization - * atomicCompareExchange(type,var,expected_var,desired) -- Compare and exchange (CAS) operation - * - * Atomic operations on flags. - * Flag type can be int, long, long long or their unsigned counterparts. - * The value of the flag can be 1 or 0. - * - * atomicFlagGetSet(var,oldvalue_var) -- Get and set the atomic counter value - * - * NOTE1: __atomic* and _Atomic implementations can be actually elaborated to support any value by changing the - * hardcoded new value passed to __atomic_exchange* from 1 to @param count - * i.e oldvalue_var = atomic_exchange_explicit(&var, count). - * However, in order to be compatible with the __sync functions family, we can use only 0 and 1. - * The only exchange alternative suggested by __sync is __sync_lock_test_and_set, - * But as described by the gnu manual for __sync_lock_test_and_set(): - * https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html - * "A target may support reduced functionality here by which the only valid value to store is the immediate constant 1. The exact value - * actually stored in *ptr is implementation defined." - * Hence, we can't rely on it for a any value other than 1. - * We eventually chose to implement this method with __sync_val_compare_and_swap since it satisfies functionality needed for atomicFlagGetSet - * (if the flag was 0 -> set to 1, if it's already 1 -> do nothing, but the final result is that the flag is set), - * and also it has a full barrier (__sync_lock_test_and_set has acquire barrier). - * - * NOTE2: Unlike other atomic type, which aren't guaranteed to be lock free, c11 atomic_flag does. - * To check whether a type is lock free, atomic_is_lock_free() can be used. - * It can be considered to limit the flag type to atomic_flag to improve performance. - * - * Never use return value from the macros, instead use the AtomicGetIncr() - * if you need to get the current value and increment it atomically, like - * in the following example: - * - * long oldvalue; - * atomicGetIncr(myvar,oldvalue,1); - * doSomethingWith(oldvalue); - * - * ---------------------------------------------------------------------------- - * - * Copyright (c) 2015-Present, Redis Ltd. - * All rights reserved. - * - * Licensed under your choice of (a) the Redis Source Available License 2.0 - * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the - * GNU Affero General Public License v3 (AGPLv3). - */ - -#include <pthread.h> -#include "config.h" - -#ifndef __ATOMIC_VAR_H -#define __ATOMIC_VAR_H - -/* Define redisAtomic for atomic variable. */ -#define redisAtomic - -/* To test Redis with Helgrind (a Valgrind tool) it is useful to define - * the following macro, so that __sync macros are used: those can be detected - * by Helgrind (even if they are less efficient) so that no false positive - * is reported. */ -// #define __ATOMIC_VAR_FORCE_SYNC_MACROS - -/* There will be many false positives if we test Redis with Helgrind, since - * Helgrind can't understand we have imposed ordering on the program, so - * we use macros in helgrind.h to tell Helgrind inter-thread happens-before - * relationship explicitly for avoiding false positives. - * - * For more details, please see: valgrind/helgrind.h and - * https://www.valgrind.org/docs/manual/hg-manual.html#hg-manual.effective-use - * - * These macros take effect only when 'make helgrind', and you must first - * install Valgrind in the default path configuration. */ -#ifdef __ATOMIC_VAR_FORCE_SYNC_MACROS -#include <valgrind/helgrind.h> -#else -#define ANNOTATE_HAPPENS_BEFORE(v) ((void) v) -#define ANNOTATE_HAPPENS_AFTER(v) ((void) v) -#endif - -#if !defined(__ATOMIC_VAR_FORCE_SYNC_MACROS) && defined(__STDC_VERSION__) && \ - (__STDC_VERSION__ >= 201112L) && !defined(__STDC_NO_ATOMICS__) -/* Use '_Atomic' keyword if the compiler supports. */ -#undef redisAtomic -#define redisAtomic _Atomic -/* Implementation using _Atomic in C11. */ - -#include <stdatomic.h> -#define atomicIncr(var,count) atomic_fetch_add_explicit(&var,(count),memory_order_relaxed) -#define atomicGetIncr(var,oldvalue_var,count) do { \ - oldvalue_var = atomic_fetch_add_explicit(&var,(count),memory_order_relaxed); \ -} while(0) -#define atomicIncrGet(var, newvalue_var, count) \ - newvalue_var = atomicIncr(var,count) + count -#define atomicDecr(var,count) atomic_fetch_sub_explicit(&var,(count),memory_order_relaxed) -#define atomicGet(var,dstvar) do { \ - dstvar = atomic_load_explicit(&var,memory_order_relaxed); \ -} while(0) -#define atomicSet(var,value) atomic_store_explicit(&var,value,memory_order_relaxed) -#define atomicGetWithSync(var,dstvar) do { \ - dstvar = atomic_load_explicit(&var,memory_order_seq_cst); \ -} while(0) -#define atomicSetWithSync(var,value) \ - atomic_store_explicit(&var,value,memory_order_seq_cst) -#define atomicCompareExchange(type,var,expected_var,desired) \ - atomic_compare_exchange_weak_explicit(&var,&expected_var,desired,memory_order_relaxed,memory_order_relaxed) -#define atomicFlagGetSet(var,oldvalue_var) \ - oldvalue_var = atomic_exchange_explicit(&var,1,memory_order_relaxed) -#define REDIS_ATOMIC_API "c11-builtin" - -#elif !defined(__ATOMIC_VAR_FORCE_SYNC_MACROS) && \ - (!defined(__clang__) || !defined(__APPLE__) || __apple_build_version__ > 4210057) && \ - defined(__ATOMIC_RELAXED) && defined(__ATOMIC_SEQ_CST) -/* Implementation using __atomic macros. */ - -#define atomicIncr(var,count) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED) -#define atomicIncrGet(var, newvalue_var, count) \ - newvalue_var = __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED) -#define atomicGetIncr(var,oldvalue_var,count) do { \ - oldvalue_var = __atomic_fetch_add(&var,(count),__ATOMIC_RELAXED); \ -} while(0) -#define atomicDecr(var,count) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED) -#define atomicGet(var,dstvar) do { \ - dstvar = __atomic_load_n(&var,__ATOMIC_RELAXED); \ -} while(0) -#define atomicSet(var,value) __atomic_store_n(&var,value,__ATOMIC_RELAXED) -#define atomicGetWithSync(var,dstvar) do { \ - dstvar = __atomic_load_n(&var,__ATOMIC_SEQ_CST); \ -} while(0) -#define atomicSetWithSync(var,value) \ - __atomic_store_n(&var,value,__ATOMIC_SEQ_CST) -#define atomicCompareExchange(type,var,expected_var,desired) \ - __atomic_compare_exchange_n(&var,&expected_var,desired,1,__ATOMIC_RELAXED,__ATOMIC_RELAXED) -#define atomicFlagGetSet(var,oldvalue_var) \ - oldvalue_var = __atomic_exchange_n(&var,1,__ATOMIC_RELAXED) -#define REDIS_ATOMIC_API "atomic-builtin" - -#elif defined(HAVE_ATOMIC) -/* Implementation using __sync macros. */ - -#define atomicIncr(var,count) __sync_add_and_fetch(&var,(count)) -#define atomicIncrGet(var, newvalue_var, count) \ - newvalue_var = __sync_add_and_fetch(&var,(count)) -#define atomicGetIncr(var,oldvalue_var,count) do { \ - oldvalue_var = __sync_fetch_and_add(&var,(count)); \ -} while(0) -#define atomicDecr(var,count) __sync_sub_and_fetch(&var,(count)) -#define atomicGet(var,dstvar) do { \ - dstvar = __sync_sub_and_fetch(&var,0); \ -} while(0) -#define atomicSet(var,value) do { \ - while(!__sync_bool_compare_and_swap(&var,var,value)); \ -} while(0) -/* Actually the builtin issues a full memory barrier by default. */ -#define atomicGetWithSync(var,dstvar) do { \ - dstvar = __sync_sub_and_fetch(&var,0,__sync_synchronize); \ - ANNOTATE_HAPPENS_AFTER(&var); \ -} while(0) -#define atomicSetWithSync(var,value) do { \ - ANNOTATE_HAPPENS_BEFORE(&var); \ - while(!__sync_bool_compare_and_swap(&var,var,value,__sync_synchronize)); \ -} while(0) -#define atomicCompareExchange(type,var,expected_var,desired) ({ \ - type _old = __sync_val_compare_and_swap(&var,expected_var,desired); \ - int _success = (_old == expected_var); \ - if (!_success) expected_var = _old; \ - _success; \ -}) -#define atomicFlagGetSet(var,oldvalue_var) \ - oldvalue_var = __sync_val_compare_and_swap(&var,0,1) -#define REDIS_ATOMIC_API "sync-builtin" - -#else -#error "Unable to determine atomic operations for your platform" - -#endif -#endif /* __ATOMIC_VAR_H */ |
