Patch "perf: Fix interrupt handler timing harness" has been added to the 3.10-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    perf: Fix interrupt handler timing harness

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-fix-interrupt-handler-timing-harness.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From e5302920da9ef23f9d19d4e9ac85704cc25bee7a Mon Sep 17 00:00:00 2001
From: Stephane Eranian <eranian@xxxxxxxxxx>
Date: Fri, 5 Jul 2013 00:30:11 +0200
Subject: perf: Fix interrupt handler timing harness

From: Stephane Eranian <eranian@xxxxxxxxxx>

commit e5302920da9ef23f9d19d4e9ac85704cc25bee7a upstream.

This patch fixes a serious bug in:

  14c63f17b1fd perf: Drop sample rate when sampling is too slow

There was an misunderstanding on the API of the do_div()
macro. It returns the remainder of the division and this
was not what the function expected leading to disabling the
interrupt latency watchdog.

This patch also remove a duplicate assignment in
perf_sample_event_took().

Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: dave.hansen@xxxxxxxxxxxxxxx
Cc: ak@xxxxxxxxxxxxxxx
Cc: jolsa@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Weng Meiling <wengmeiling.weng@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/events/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -182,7 +182,7 @@ void update_perf_cpu_limits(void)
 	u64 tmp = perf_sample_period_ns;
 
 	tmp *= sysctl_perf_cpu_time_max_percent;
-	tmp = do_div(tmp, 100);
+	do_div(tmp, 100);
 	atomic_set(&perf_sample_allowed_ns, tmp);
 }
 
@@ -230,7 +230,7 @@ DEFINE_PER_CPU(u64, running_sample_lengt
 void perf_sample_event_took(u64 sample_len_ns)
 {
 	u64 avg_local_sample_len;
-	u64 local_samples_len = __get_cpu_var(running_sample_length);
+	u64 local_samples_len;
 
 	if (atomic_read(&perf_sample_allowed_ns) == 0)
 		return;


Patches currently in stable-queue which might be from eranian@xxxxxxxxxx are

queue-3.10/perf-fix-interrupt-handler-timing-harness.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]