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
Status: CLOSED UNREPRODUCIBLE
Alias: None
Product: Power Management
Classification: Unclassified
Component: Hibernation/Suspend (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: power-management_other
URL:
Keywords:
Depends on:
Blocks:
 
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
Subsystem:
Regression: No
Bisected commit-id:

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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.

Chris,
Can you attach the "add" program?
can you please verify if the problem still exists in the latest upstream
kernel?
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.
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