gnustep/libs-base
0
0
Fork 0
mirror of https://github.com/gnustep/libs-base.git synced 2025-05-30 16:30:41 +00:00
Code Issues Projects Releases Packages Wiki Activity

Merge pull request #42 from triplef/nsthread-spinlock-builtin

Browse source 
Added basic spinlock implementation using builtins.
This commit is contained in:
rfm 2019-05-20 14:47:33 +01:00 • committed by GitHub
commit fa34c66e25
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 22 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

25
Source/NSThread.m
View file

@ -38,21 +38,40 @@
// Dummy implementatation // Dummy implementatation
// cleaner than IFDEF'ing the code everywhere // cleaner than IFDEF'ing the code everywhere
#if !(HAVE_PTHREAD_SPIN_LOCK) #if !(HAVE_PTHREAD_SPIN_LOCK)
#warning no spin_locks, using dummy versions typedef volatile int pthread_spinlock_t;
typedef int pthread_spinlock_t;
int pthread_spin_init(pthread_spinlock_t *lock, int pshared) int pthread_spin_init(pthread_spinlock_t *lock, int pshared)
{ {
#if DEBUG #if DEBUG && !__has_builtin(__sync_bool_compare_and_swap)
fprintf(stderr,"NSThread.m: Warning this platform does not support spin locks - init.\n"); fprintf(stderr,"NSThread.m: Warning this platform does not support spin locks - init.\n");
#endif #endif
return 0; return 0;
} }
int pthread_spin_lock(pthread_spinlock_t *lock) int pthread_spin_lock(pthread_spinlock_t *lock)
{ {
#if __has_builtin(__sync_bool_compare_and_swap)
int count = 0;
// Set the spin lock value to 1 if it is 0.
while(!__sync_bool_compare_and_swap(lock, 0, 1))
{
count++;
if (0 == count % 10)
{
// If it is already 1, let another thread play with the CPU for a
// bit then try again.
sleep(0);
}
}
#else
#warning no spin_locks, using dummy versions
#endif
return 0; return 0;
} }
int pthread_spin_unlock(pthread_spinlock_t *lock) int pthread_spin_unlock(pthread_spinlock_t *lock)
{ {
#if __has_builtin(__sync_bool_compare_and_swap)
__sync_synchronize();
*lock = 0;
#endif
return 0; return 0;
} }
int pthread_spin_destroy(pthread_spinlock_t *lock) int pthread_spin_destroy(pthread_spinlock_t *lock)