Re: [PATCH] sched: Reduce contention in update_cfs_rq_blocked_load

[Jason Low <jason.low2@hp.com>]

On Tue, 2014-08-05 at 03:15 +0800, Yuyang Du wrote:
> Hi Jason,
> 
> I am not sure whether you noticed my latest work: rewriting per entity load average
> 
> http://article.gmane.org/gmane.linux.kernel/1760754
> http://article.gmane.org/gmane.linux.kernel/1760755
> http://article.gmane.org/gmane.linux.kernel/1760757
> http://article.gmane.org/gmane.linux.kernel/1760756
> 
> which simply does not track blocked load average at all. Are you interested in
> testing the patchset with the workload you have?

Hi Yuyang,

I ran these tests with most of the AIM7 workloads to compare its
performance between a 3.16 kernel and the kernel with these patches
applied.

The table below contains the percent difference between the baseline
kernel and the kernel with the patches at various user counts. A
positive percent means the kernel with the patches performed better,
while a negative percent means the baseline performed better.

Based on these numbers, for many of the workloads, the change was
beneficial in those highly contended, while it had - impact in many
of the lightly/moderately contended case (10 to 90 users).

-----------------------------------------------------
              |   10-90   |  100-1000   |  1100-2000
              |   users   |   users     |   users
-----------------------------------------------------
alltests      |   -3.37%  |  -10.64%    |   -2.25%
-----------------------------------------------------
all_utime     |   +0.33%  |   +3.73%    |   +3.33%
-----------------------------------------------------
compute       |   -5.97%  |   +2.34%    |   +3.22%
-----------------------------------------------------
custom        |  -31.61%  |  -10.29%    |  +15.23%
-----------------------------------------------------
disk          |  +24.64%  |  +28.96%    |  +21.28%
-----------------------------------------------------
fserver       |   -1.35%  |   +4.82%    |   +9.35%
-----------------------------------------------------
high_systime  |   -6.73%  |   -6.28%    |  +12.36%
-----------------------------------------------------
shared        |  -28.31%  |  -19.99%    |   -7.10%
-----------------------------------------------------
short         |  -44.63%  |  -37.48%    |  -33.62%
-----------------------------------------------------