On 11/09/2012 10:22 PM, Srivatsa S. Bhat wrote:

On 11/09/2012 10:13 PM, Srivatsa S. Bhat wrote:

quoted

On 11/09/2012 10:04 PM, Srivatsa S. Bhat wrote:

quoted

On 11/09/2012 09:43 PM, Dave Hansen wrote:

quoted

On 11/09/2012 07:23 AM, Srivatsa S. Bhat wrote:

quoted

FWIW, kernbench is actually (and surprisingly) showing a slight performance
*improvement* with this patchset, over vanilla 3.7-rc3, as I mentioned in
my other email to Dave.

https://lkml.org/lkml/2012/11/7/428

I don't think I can dismiss it as an experimental error, because I am seeing
those results consistently.. I'm trying to find out what's behind that.

The only numbers in that link are in the date. :)  Let's see the
numbers, please.

Sure :) The reason I didn't post the numbers very eagerly was that I didn't
want it to look ridiculous if it later turned out to be really an error in the
experiment ;) But since I have seen it happening consistently I think I can
post the numbers here with some non-zero confidence.

quoted

If you really have performance improvement to the memory allocator (or
something else) here, then surely it can be pared out of your patches
and merged quickly by itself.  Those kinds of optimizations are hard to
come by!

:-)

Anyway, here it goes:

Test setup:
----------
x86 2-socket quad-core machine. (CONFIG_NUMA=n because I figured that my
patchset might not handle NUMA properly). Mem region size = 512 MB.

For CONFIG_NUMA=y on the same machine, the difference between the 2 kernels
was much lesser, but nevertheless, this patchset performed better. I wouldn't
vouch that my patchset handles NUMA correctly, but here are the numbers from
that run anyway (at least to show that I really found the results to be
repeatable):

I fixed up the NUMA case (I'll post the updated patch for that soon) and
ran a fresh set of kernbench runs. The difference between mainline and this
patchset is quite tiny; so we can't really say that this patchset shows a
performance improvement over mainline. However, I can safely conclude that
this patchset doesn't show any performance _degradation_ w.r.t mainline
in kernbench.

Results from one of the recent kernbench runs:
---------------------------------------------

Kernbench log for Vanilla 3.7-rc3
=================================
Kernel: 3.7.0-rc3
Average Optimal load -j 32 Run (std deviation):
Elapsed Time 330.39 (0.746257)
User Time 4283.63 (3.39617)
System Time 604.783 (2.72629)
Percent CPU 1479 (3.60555)
Context Switches 845634 (6031.22)
Sleeps 833655 (6652.17)


Kernbench log for Sorted-buddy
==============================
Kernel: 3.7.0-rc3-sorted-buddy
Average Optimal load -j 32 Run (std deviation):
Elapsed Time 329.967 (2.76789)
User Time 4230.02 (2.15324)
System Time 599.793 (1.09988)
Percent CPU 1463.33 (11.3725)
Context Switches 840530 (1646.75)
Sleeps 833732 (2227.68)

Regards,
Srivatsa S. Bhat