2009-12-01 09:31:44

by Xiao Guangrong

Subject: [PATCH] perf_event: initialize data.period in perf_swevent_hrtimer()

In current code in perf_swevent_hrtimer(), data.period is not initialized,
The result is obvious wrong:

# ./perf record -f -e cpu-clock make
# ./perf report
# Samples: 1740
#
# Overhead Command ......
# ........ ........ ..........................................
#
1025422183050275328.00% sh libc-2.9.90.so ...
1025422183050275328.00% perl libperl.so ...
1025422168240043264.00% perl [kernel] ...
1025422030011210752.00% perl [kernel] ...

Signed-off-by: Xiao Guangrong <[email protected]>
---
kernel/perf_event.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 0b9ca2d..040ee51 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4010,6 +4010,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
event->pmu->read(event);

data.addr = 0;
+ data.period = event->hw.last_period;
regs = get_irq_regs();
/*
* In case we exclude kernel IPs or are somehow not in interrupt
--
1.6.1.2

2009-12-01 09:37:09

by Peter Zijlstra

Subject: Re: [PATCH] perf_event: initialize data.period in perf_swevent_hrtimer()

On Tue, 2009-12-01 at 17:30 +0800, Xiao Guangrong wrote:
> In current code in perf_swevent_hrtimer(), data.period is not initialized,

Ah, very nice catch.

Acked-by: Peter Zijlstra <[email protected]>

> Signed-off-by: Xiao Guangrong <[email protected]>
> ---
> kernel/perf_event.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/perf_event.c b/kernel/perf_event.c
> index 0b9ca2d..040ee51 100644
> --- a/kernel/perf_event.c
> +++ b/kernel/perf_event.c
> @@ -4010,6 +4010,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
> event->pmu->read(event);
>
> data.addr = 0;
> + data.period = event->hw.last_period;
> regs = get_irq_regs();
> /*
> * In case we exclude kernel IPs or are somehow not in interrupt

2009-12-01 10:22:19

by Xiao Guangrong

Subject: [tip:perf/core] perf_event: Initialize data.period in perf_swevent_hrtimer()

Commit-ID: 59d069eb5ae9b033ed1c124c92e1532c4a958991
Gitweb: http://git.kernel.org/tip/59d069eb5ae9b033ed1c124c92e1532c4a958991
Author: Xiao Guangrong <[email protected]>
AuthorDate: Tue, 1 Dec 2009 17:30:08 +0800
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 1 Dec 2009 11:19:07 +0100

perf_event: Initialize data.period in perf_swevent_hrtimer()

In current code in perf_swevent_hrtimer(), data.period is not
initialized, The result is obvious wrong:

# ./perf record -f -e cpu-clock make
# ./perf report
# Samples: 1740
#
# Overhead Command ......
# ........ ........ ..........................................
#
1025422183050275328.00% sh libc-2.9.90.so ...
1025422183050275328.00% perl libperl.so ...
1025422168240043264.00% perl [kernel] ...
1025422030011210752.00% perl [kernel] ...

Signed-off-by: Xiao Guangrong <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/perf_event.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 0b9ca2d..040ee51 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4010,6 +4010,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
event->pmu->read(event);

data.addr = 0;
+ data.period = event->hw.last_period;
regs = get_irq_regs();
/*
* In case we exclude kernel IPs or are somehow not in interrupt