Re: [Bug #11308] tbench regression on each kernel release from2.6.22 -> 2.6.28

[Ingo Molnar]

* Rafael J. Wysocki <rjw@xxxxxxx> wrote:

> This message has been generated automatically as a part of a report
> of regressions introduced between 2.6.26 and 2.6.27.
> 
> The following bug entry is on the current list of known regressions
> introduced between 2.6.26 and 2.6.27.  Please verify if it still should
> be listed and let me know (either way).
> 
> 
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=11308
> Subject		: tbench regression on each kernel release from  2.6.22 -&gt; 2.6.28
> Submitter	: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
> Date		: 2008-08-11 18:36 (98 days old)
> References	: http://marc.info/?l=linux-kernel&m=121847986119495&w=4
> 		  http://marc.info/?l=linux-kernel&m=122125737421332&w=4

Christoph, as per the recent analysis of Mike:

 http://fixunix.com/kernel/556867-regression-benchmark-throughput-loss-a622cf6-f7160c7-pull.html

all scheduler components of this regression have been eliminated.

In fact his numbers show that scheduler speedups since 2.6.22 have 
offset and hidden most other sources of tbench regression. (i.e. the 
scheduler portion got 5% faster, hence it was able to offset a 
slowdown of 5% in other areas of the kernel that tbench triggers)

	Ingo
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