Bug 16567 - Increase of performance for single threaded program after suspend on a core i7
Summary: Increase of performance for single threaded program after suspend on a core i7
Alias: None
Product: Power Management
Classification: Unclassified
Component: Hibernation/Suspend (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: power-management_other
Depends on:
Reported: 2010-08-12 08:10 UTC by ChriS
Modified: 2012-02-02 06:07 UTC (History)
1 user (show)

See Also:
Kernel Version: 2.6.35
Tree: Mainline
Regression: No


Description ChriS 2010-08-12 08:10:55 UTC
I have 

  Thinkpad W510, Core i7 Q 820  @ 1.73GHz
  Distribution: Debian (testing)
  Linux poincare 2.6.35 #1 SMP Thu Aug 12 08:59:35 CEST 2010 x86_64 GNU/Linux

On a fresh boot, the attached "add" program has the following performance:

3.54user 0.00system 0:03.57elapsed 99%CPU (0avgtext+0avgdata 2032maxresident)k
0inputs+0outputs (0major+169minor)pagefaults 0swaps

However, after I suspend (to RAM) the machine, I see a dramatic improvement in speed:

1.45user 0.00system 0:01.46elapsed 99%CPU (0avgtext+0avgdata 2032maxresident)k
0inputs+0outputs (0major+169minor)pagefaults 0swaps

It would be nice to have that performance on first boot!  Note that this is not true for multi-threaded programs (see for example the times fot the compilation of the kernel reported in bug #15559).
Comment 1 Zhang Rui 2012-01-18 02:16:57 UTC
It's great that kernel bugzilla is back.

Can you attach the "add" program?
can you please verify if the problem still exists in the latest upstream
Comment 2 ChriS 2012-01-20 10:06:07 UTC
> Can you attach the "add" program?

Oh, well, I thought I did!  I am afraid I do not have it anymore.

However the good thing is that I am using 3.1.4 now and I do not have the problem anymore.
Comment 3 Zhang Rui 2012-02-02 06:07:18 UTC
Okay, bug closed. Please feel free to reopen it when you run into this problem again.

Note You need to log in before you can comment on or make changes to this bug.