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MINOR: thread: implement ha_thread_relax()

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At some places we're using a painful ifdef to decide whether to use
sched_yield() or pl_cpu_relax() to relax in loops, this is hardly
exportable. Let's move this to ha_thread_relax() instead and une
this one only.
This commit is contained in:
Willy Tarreau 2019-05-17 16:33:13 +02:00
parent 20db9115dc
commit 38171daf21
2 changed files with 23 additions and 10 deletions
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21
include/common/hathreads.h
View File

@ -22,6 +22,11 @@
#ifndef _COMMON_HATHREADS_H #ifndef _COMMON_HATHREADS_H
#define _COMMON_HATHREADS_H #define _COMMON_HATHREADS_H
#include <unistd.h>
#ifdef _POSIX_PRIORITY_SCHEDULING
#include <sched.h>
#endif
#include <common/config.h> #include <common/config.h>
#include <common/initcall.h> #include <common/initcall.h>
@ -130,6 +135,13 @@ static inline void ha_set_tid(unsigned int tid)
{ {
} }
static inline void ha_thread_relax(void)
{
#if _POSIX_PRIORITY_SCHEDULING
sched_yield();
#endif
}
static inline void __ha_barrier_atomic_load(void) static inline void __ha_barrier_atomic_load(void)
{ {
} }
@ -391,6 +403,15 @@ static inline void ha_set_tid(unsigned int data)
tid_bit = (1UL << tid); tid_bit = (1UL << tid);
} }
static inline void ha_thread_relax(void)
{
#if _POSIX_PRIORITY_SCHEDULING
sched_yield();
#else
pl_cpu_relax();
#endif
}
/* Marks the thread as harmless. Note: this must be true, i.e. the thread must /* Marks the thread as harmless. Note: this must be true, i.e. the thread must
* not be touching any unprotected shared resource during this period. Usually * not be touching any unprotected shared resource during this period. Usually
* this is called before poll(), but it may also be placed around very slow * this is called before poll(), but it may also be placed around very slow

12
src/hathreads.c
View File

@ -52,11 +52,7 @@ void thread_harmless_till_end()
{ {
_HA_ATOMIC_OR(&threads_harmless_mask, tid_bit); _HA_ATOMIC_OR(&threads_harmless_mask, tid_bit);
while (threads_want_rdv_mask & all_threads_mask) { while (threads_want_rdv_mask & all_threads_mask) {
#if _POSIX_PRIORITY_SCHEDULING ha_thread_relax();
sched_yield();
#else
pl_cpu_relax();
#endif
} }
} }
@ -81,11 +77,7 @@ void thread_isolate()
else if (_HA_ATOMIC_CAS(&threads_harmless_mask, &old, old & ~tid_bit)) else if (_HA_ATOMIC_CAS(&threads_harmless_mask, &old, old & ~tid_bit))
break; break;
#if _POSIX_PRIORITY_SCHEDULING ha_thread_relax();
sched_yield();
#else
pl_cpu_relax();
#endif
} }
/* one thread gets released at a time here, with its harmess bit off. /* one thread gets released at a time here, with its harmess bit off.
* The loss of this bit makes the other one continue to spin while the * The loss of this bit makes the other one continue to spin while the