Commit-ID: a94cab2376cb35f236be14e2833cef63a8762a31
Gitweb: http://git.kernel.org/tip/a94cab2376cb35f236be14e2833cef63a8762a31
Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Sun, 10 May 2015 12:22:39 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Aug 2015 10:16:55 +0200
perf/x86: Add a native_perf_sched_clock_from_tsc()
PEBSv3 has a raw TSC time stamp in its memory buffer that
later needs to to be converted to perf_clock.
Add a native_sched_clock_from_tsc() that works the same
as native_sched_clock(), but starts with an already given
TSC value.
Paravirt is ignored, it will just get the native clock.
But there isn't a para virtualized PEBS anyway.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: eranian@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1431285767-27027-2-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/tsc.h | 1 +
arch/x86/kernel/tsc.c | 8 ++++++++
2 files changed, 9 insertions(+)
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 94605c0..aad56eb 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -51,6 +51,7 @@ extern int unsynchronized_tsc(void);
extern int check_tsc_unstable(void);
extern int check_tsc_disabled(void);
extern unsigned long native_calibrate_tsc(void);
+extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
extern int tsc_clocksource_reliable;
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 7437b41..88e9a38 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -296,6 +296,14 @@ u64 native_sched_clock(void)
return cycles_2_ns(tsc_now);
}
+/*
+ * Generate a sched_clock if you already have a TSC value.
+ */
+u64 native_sched_clock_from_tsc(u64 tsc)
+{
+ return cycles_2_ns(tsc);
+}
+
/* We need to define a real function for sched_clock, to override the
weak default version */
#ifdef CONFIG_PARAVIRT
--
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