Thanks for your explanations. It helped greatly. Using ktrdump and
schedgraph.py and after modifying our test program to set and unset
automatically debug.ktr.mask, I've been able to get useful information.
First, It made me realize that task switching, with default settings and
2 active
on 24/02/2011 16:18 Jerome Flesch said the following:
Thanks for your explanations. It helped greatly. Using ktrdump and
schedgraph.py
and after modifying our test program to set and unset automatically
debug.ktr.mask, I've been able to get useful information.
First, It made me realize
On Thursday, February 24, 2011 12:34:04 pm Andriy Gapon wrote:
on 24/02/2011 16:18 Jerome Flesch said the following:
Thanks for your explanations. It helped greatly. Using ktrdump and
schedgraph.py
and after modifying our test program to set and unset automatically
debug.ktr.mask, I've
On 22/02/2011, at 2:54, Jerome Flesch wrote:
While investigating a timing issue with one of our program, we found out
something weird: We've written a small test program that just calls
clock_gettime() a lot of times and checks that the time difference between
calls makes sense. In the
On Feb 21, 2011, at 8:24 AM, Jerome Flesch wrote:
While investigating a timing issue with one of our program, we found out
something weird: We've written a small test program that just calls
clock_gettime() a lot of times and checks that the time difference between
calls makes sense. In the
On Feb 22, 2011, at 1:22 AM, Jerome Flesch wrote:
A scheduler quantum of 10ms (or HZ=100) is a common granularity; probably
some other process got the CPU and your timer process didn't run until the
next or some later scheduler tick. If you are maxing out the available CPU
by running many
Jerome Flesch wrote this message on Tue, Feb 22, 2011 at 10:22 +0100:
We expected both processes (the test program and openssl) to have each
half the CPU time and being scheduled quite often (at least once each
10ms). According to the output of our test program, it works fine for
most of
To debug weird scheduling issues I find it helpful to start by looking
at a schedgraph. schedgraph is a tool that can display a graphical
representation of what the scheduler was doing over a small slice of
time. The one downside is that you have to recompile your kernel to
get the hooks that
On Feb 21, 2011, at 8:24 AM, Jerome Flesch wrote:
While investigating a timing issue with one of our program, we found out
something weird: We've written a small test program that just calls
clock_gettime() a lot of times and checks that the time difference between
calls makes sense. In the
