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Linux: Use rseq to accelerate sched_getcpu

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Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
This commit is contained in:
Florian Weimer 2021-12-09 09:49:32 +01:00
parent 95e114a091
commit 1d350aa060
1 changed files with 17 additions and 2 deletions
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19
sysdeps/unix/sysv/linux/sched_getcpu.c
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@ -20,8 +20,8 @@
#include <sysdep.h> #include <sysdep.h>
#include <sysdep-vdso.h> #include <sysdep-vdso.h>
int static int
sched_getcpu (void) vsyscall_sched_getcpu (void)
{ {
unsigned int cpu; unsigned int cpu;
int r = -1; int r = -1;
@ -32,3 +32,18 @@ sched_getcpu (void)
#endif #endif
return r == -1 ? r : cpu; return r == -1 ? r : cpu;
} }
#ifdef RSEQ_SIG
int
sched_getcpu (void)
{
int cpu_id = THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id);
return __glibc_likely (cpu_id >= 0) ? cpu_id : vsyscall_sched_getcpu ();
}
#else /* RSEQ_SIG */
int
sched_getcpu (void)
{
return vsyscall_sched_getcpu ();
}
#endif /* RSEQ_SIG */