| commit 1d350aa06091211863e41169729cee1bca39f72f |
| Author: Florian Weimer <fweimer@redhat.com> |
| Date: Thu Dec 9 09:49:32 2021 +0100 |
| |
| Linux: Use rseq to accelerate sched_getcpu |
| |
| Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> |
| |
| diff --git a/sysdeps/unix/sysv/linux/sched_getcpu.c b/sysdeps/unix/sysv/linux/sched_getcpu.c |
| index c41e986f2cab5e42..6f78edaea1495342 100644 |
| |
| |
| @@ -20,8 +20,8 @@ |
| #include <sysdep.h> |
| #include <sysdep-vdso.h> |
| |
| -int |
| -sched_getcpu (void) |
| +static int |
| +vsyscall_sched_getcpu (void) |
| { |
| unsigned int cpu; |
| int r = -1; |
| @@ -32,3 +32,18 @@ sched_getcpu (void) |
| #endif |
| 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 */ |