diff options
| -rw-r--r-- | linuxthreads/ChangeLog | 9 | ||||
| -rw-r--r-- | linuxthreads/internals.h | 7 | ||||
| -rw-r--r-- | linuxthreads/spinlock.c | 6 | ||||
| -rw-r--r-- | linuxthreads/sysdeps/i386/i686/pt-machine.h | 3 |
4 files changed, 25 insertions, 0 deletions
diff --git a/linuxthreads/ChangeLog b/linuxthreads/ChangeLog index 1ce5a23186..b85f8c94df 100644 --- a/linuxthreads/ChangeLog +++ b/linuxthreads/ChangeLog @@ -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 diff --git a/linuxthreads/internals.h b/linuxthreads/internals.h index d5b469b347..ae49266278 100644 --- a/linuxthreads/internals.h +++ b/linuxthreads/internals.h @@ -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. diff --git a/linuxthreads/spinlock.c b/linuxthreads/spinlock.c index 199386a4fc..3e16825997 100644 --- a/linuxthreads/spinlock.c +++ b/linuxthreads/spinlock.c @@ -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)); } diff --git a/linuxthreads/sysdeps/i386/i686/pt-machine.h b/linuxthreads/sysdeps/i386/i686/pt-machine.h index 7df3e7e487..c7396024bb 100644 --- a/linuxthreads/sysdeps/i386/i686/pt-machine.h +++ b/linuxthreads/sysdeps/i386/i686/pt-machine.h @@ -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") |