On 09/05/2012 05:44 AM, Sergey Senozhatsky wrote:
Hi,
On (09/05/12 15:52), Rajagopal Venkat wrote:
Incorrect timer and work perf events timestamp tracing is one
of the reason for reporting usage over 100%. This patch will
resolve the issue by
- rejecting the events for which entry timestamp is not recorded.
how is that possible?
do you mean erasing between measurements?
schematically:
measure0:
ev1.start
ev2.start
ev2.end
processing
clear
measure1:
ev3.start
ev1.end <<<<<
ev3.end
processing
clear
if so, then we're loosing events, which is no good. reporting less than 100%
is ok, but reporting less than real is not.
p.s.
I'll try to check emails, but most probably will be off-line most of the day.
-ss
Yes! This is a hard issues. Some report say CPU usage over 100% which in
some cases is correct. For instance for IA, a CPU can run over 100% of
it's listed frequency. For instance listed freq could be 3.4 but in
turbo mode the freq govonor can request max and be given 3.8Ghz for a
duration. Also overall if all processor cores are running at 100% you
essentially can have a overall usage of over 100%.
There have been some cases reported where CPU usage is WAY over 100% and
that is an issue, but I have has a hard time reproducing the issues.
This can be tricky business, so care is needed.
-Chris
Currently these events exit timestamp itself is considered as
usage period resulting in over 100% usage.
- clearing event timestamps from global map at the end of each
measurement to avoid collision with earlier recorded timestamps.
Signed-off-by: Rajagopal Venkat <rajagopal.ven...@linaro.org>
---
src/process/timer.cpp | 5 ++++-
src/process/work.cpp | 5 ++++-
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/process/timer.cpp b/src/process/timer.cpp
index 8917490..db074c4 100644
--- a/src/process/timer.cpp
+++ b/src/process/timer.cpp
@@ -79,7 +79,8 @@ uint64_t timer::done(uint64_t time, uint64_t timer_struct)
{
int64_t delta;
- if (running_since[timer_struct] > time)
+ if (running_since.find(timer_struct) == running_since.end() ||
+ running_since[timer_struct] > time)
return 0;
delta = time - running_since[timer_struct];
@@ -147,6 +148,8 @@ void clear_timers(void)
all_timers.erase(it);
it = all_timers.begin();
}
+
+ running_since.clear();
}
bool timer::is_deferred(void)
diff --git a/src/process/work.cpp b/src/process/work.cpp
index 82f13a2..e436643 100644
--- a/src/process/work.cpp
+++ b/src/process/work.cpp
@@ -56,7 +56,8 @@ uint64_t work::done(uint64_t time, uint64_t work_struct)
{
int64_t delta;
- if (running_since[work_struct] > time)
+ if (running_since.find(work_struct) == running_since.end() ||
+ running_since[work_struct] > time)
return 0;
delta = time - running_since[work_struct];
@@ -102,6 +103,8 @@ void clear_work(void)
all_work.erase(it);
it = all_work.begin();
}
+
+ running_since.clear();
}
--
1.7.11.3
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