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authorMitja Felicijan <mitja.felicijan@gmail.com>2026-01-21 22:52:54 +0100
committerMitja Felicijan <mitja.felicijan@gmail.com>2026-01-21 22:52:54 +0100
commitdcacc00e3750300617ba6e16eb346713f91a783a (patch)
tree38e2d4fb5ed9d119711d4295c6eda4b014af73fd /examples/redis-unstable/src/atomicvar.h
parent58dac10aeb8f5a041c46bddbeaf4c7966a99b998 (diff)
downloadcrep-dcacc00e3750300617ba6e16eb346713f91a783a.tar.gz
Remove testing data
Diffstat (limited to 'examples/redis-unstable/src/atomicvar.h')
-rw-r--r--examples/redis-unstable/src/atomicvar.h186
1 files changed, 0 insertions, 186 deletions
diff --git a/examples/redis-unstable/src/atomicvar.h b/examples/redis-unstable/src/atomicvar.h
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--- a/examples/redis-unstable/src/atomicvar.h
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-/* 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 */