49 lines
1.2 KiB
Diff
49 lines
1.2 KiB
Diff
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From 00bae0eb5212a1ec4e8b4b90294937903628e7ce Mon Sep 17 00:00:00 2001
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From: Florian Weimer <fweimer@redhat.com>
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Date: Thu, 9 Dec 2021 09:49:32 +0100
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Subject: [PATCH 5/9] 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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---
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sysdeps/unix/sysv/linux/sched_getcpu.c | 19 +++++++++++++++++--
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1 file changed, 17 insertions(+), 2 deletions(-)
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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 c41e986f..6f78edae 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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--
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2.23.0
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