On Tue, Jun 4, 2013 at 10:21 AM, Launchpad Bug Tracker
<1187...@bugs.launchpad.net> wrote:
> Anthony Wong (anthonywong) has assigned this bug to you for linux-lts-raring
> in Ubuntu:
>
> [Lenovo L530]: Fails cpu stress test
>
> Problem:
>
> System fails multiple attempts at passing cpu stress test using raring-
> lts kernel 3.8.0-23-generic #34~precise1. System was able to succesfully
> pass using default 12.04.2 kernel 3.5.0-23.
>
> command used:
>
> stress --cpu `cpuinfo_resource | awk '/count:/ {print $2}'` --vm `awk
> '/MemTotal/ {num_vm = $2/262144; if (num_vm != int(num_vm)) num_vm =
> int(num_vm) + 1; print num_vm}' /proc/meminfo` --timeout 7200
After reading the stress code, I think I can understand the idea
behind the test.
The above tests on both cpu and anonymous memory(swap) pressure.
Given code of 'cpuinfo_resource' isn't intact, suppose the cpu count passed is
N, which is the actual count of CPU in the machine, then 'stress' will fork N
processes, and run below code in each context:
while (1)
sqrt (rand ());
About the vm test, the passed parameter of '--vm' should be 7, and 'stress'
forks 7 children processes and run below code in each child process:
while (1) {
buf = malloc(256M);
write 'Z' to the 1st byte of each page in 'buf';
free(buf);
}
For every children process, alarm(timeout) is called beforehand to deliver a
ALARM signal to terminate it after 'timeout' seconds. "stress" thinks the
test is OK when it finds all children processes exits successfully.
Basically we need to know which children processes aren't exited successfully
so that the problem can be diagnosed:
- if 'cpu' child tasks exited abnormally or can't be exited,
the problem might
be in scheduler
- if 'vm' child tasks exited abnormally or can't be exited,
the problem might
be in swap/vm/or disk performance.
Then corresponding tests can be proposed to narrow down the problem
further.
Thanks,
--
Ming Lei
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https://bugs.launchpad.net/bugs/1187170
Title:
[Lenovo L530]: Fails cpu stress test
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