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authorFlorian Weimer <fweimer@redhat.com>2021-12-09 09:49:32 +0100
committerFlorian Weimer <fweimer@redhat.com>2021-12-09 09:49:32 +0100
commit1d350aa06091211863e41169729cee1bca39f72f (patch)
treeb091608172a4dd91bf7dfbec91d1ff0aea7d0098 /sysdeps
parent95e114a0919d844d8fe07839cb6538b7f5ee920e (diff)
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Linux: Use rseq to accelerate sched_getcpu
Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/unix/sysv/linux/sched_getcpu.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/sysdeps/unix/sysv/linux/sched_getcpu.c b/sysdeps/unix/sysv/linux/sched_getcpu.c
index c41e986..6f78eda 100644
--- a/sysdeps/unix/sysv/linux/sched_getcpu.c
+++ b/sysdeps/unix/sysv/linux/sched_getcpu.c
@@ -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 */