forked from rpms/glibc
44 lines
1.1 KiB
Diff
44 lines
1.1 KiB
Diff
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commit 1d350aa06091211863e41169729cee1bca39f72f
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Thu Dec 9 09:49:32 2021 +0100
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Linux: Use rseq to accelerate sched_getcpu
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Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
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diff --git a/sysdeps/unix/sysv/linux/sched_getcpu.c b/sysdeps/unix/sysv/linux/sched_getcpu.c
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index c41e986f2cab5e42..6f78edaea1495342 100644
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--- a/sysdeps/unix/sysv/linux/sched_getcpu.c
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+++ b/sysdeps/unix/sysv/linux/sched_getcpu.c
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@@ -20,8 +20,8 @@
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#include <sysdep.h>
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#include <sysdep-vdso.h>
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-int
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-sched_getcpu (void)
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+static int
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+vsyscall_sched_getcpu (void)
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{
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unsigned int cpu;
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int r = -1;
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@@ -32,3 +32,18 @@ sched_getcpu (void)
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#endif
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return r == -1 ? r : cpu;
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}
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+
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+#ifdef RSEQ_SIG
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+int
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+sched_getcpu (void)
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+{
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+ int cpu_id = THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id);
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+ return __glibc_likely (cpu_id >= 0) ? cpu_id : vsyscall_sched_getcpu ();
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+}
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+#else /* RSEQ_SIG */
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+int
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+sched_getcpu (void)
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+{
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+ return vsyscall_sched_getcpu ();
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+}
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+#endif /* RSEQ_SIG */
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