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2001-08-29  Ulrich Drepper  <drepper@redhat.com>

	* spinlock.c (__pthread_lock): Top max_count value with
	MAX_ADAPTIVE_SPIN_COUNT.
	* internals.h (MAX_ADAPTIVE_SPIN_COUNT): Define if not already done.

	* sysdeps/i386/i686/pt-machine.h (BUSY_WAIT_NOP): New macro to
	help P4.
This commit is contained in:
Ulrich Drepper 2001-08-30 02:13:26 +00:00
parent 6c3ebebd1e
commit 746802f20f
4 changed files with 25 additions and 0 deletions
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9
linuxthreads/ChangeLog
View File

@ -1,3 +1,12 @@
2001-08-29 Ulrich Drepper <drepper@redhat.com>
* spinlock.c (__pthread_lock): Top max_count value with
MAX_ADAPTIVE_SPIN_COUNT.
* internals.h (MAX_ADAPTIVE_SPIN_COUNT): Define if not already done.
* sysdeps/i386/i686/pt-machine.h (BUSY_WAIT_NOP): New macro to
help P4.
2001-08-27 Jakub Jelinek <jakub@redhat.com>
* sysdeps/pthread/bits/libc-lock.h (__libc_rwlock_t): Only define to

7
linuxthreads/internals.h
View File

@ -414,6 +414,13 @@ static inline pthread_descr thread_self (void)
#define MAX_SPIN_COUNT 50
#endif
/* Max number of times the spinlock in the adaptive mutex implementation
spins actively on SMP systems. */
#ifndef MAX_ADAPTIVE_SPIN_COUNT
#define MAX_ADAPTIVE_SPIN_COUNT 100
#endif
/* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
after MAX_SPIN_COUNT iterations of sched_yield().
With the 2.0 and 2.1 kernels, this MUST BE > 2ms.

6
linuxthreads/spinlock.c
View File

@ -94,6 +94,9 @@ again:
if (__pthread_smp_kernel) {
int max_count = lock->__spinlock * 2 + 10;
if (max_count > MAX_ADAPTIVE_SPIN_COUNT)
max_count = MAX_ADAPTIVE_SPIN_COUNT;
for (spin_count = 0; spin_count < max_count; spin_count++) {
if (((oldstatus = lock->__status) & 1) == 0) {
if(__compare_and_swap(&lock->__status, oldstatus, oldstatus | 1))
@ -104,6 +107,9 @@ again:
return;
}
}
#ifdef BUSY_WAIT_NOP
BUSY_WAIT_NOP;
#endif
__asm __volatile ("" : "=m" (lock->__status) : "0" (lock->__status));
}

3
linuxthreads/sysdeps/i386/i686/pt-machine.h
View File

@ -64,3 +64,6 @@ __compare_and_swap (long int *p, long int oldval, long int newval)
#if __ASSUME_LDT_WORKS > 0
#include "../useldt.h"
#endif
/* The P4 and above really want some help to prevent overheating. */
#define BUSY_WAIT_NOP __asm__ ("rep; nop")