Re: [PATCH 00/27] Latest numa/core release, v16

From: Ingo Molnar
Date: Mon Nov 19 2012 - 17:36:00 EST



* Mel Gorman <mgorman@xxxxxxx> wrote:

> Ok.
>
> In response to one of your later questions, I found that I had
> in fact disabled THP without properly reporting it. [...]

Hugepages is a must for most forms of NUMA/HPC. This alone
questions the relevance of most of your prior numa/core testing
results. I now have to strongly dispute your other conclusions
as well.

Just a look at 'perf top' output should have told you the story.

Yet time and time again you readily reported bad 'schednuma'
results for a slow 4K memory model that neither we nor other
NUMA testers I talked to actually used, without stopping to look
why that was so...

[ I suspect that if such terabytes-of-data workloads are forced
through such a slow 4K pages model then there's a bug or
mis-tuning in our code that explains the level of additional
slowdown you saw - we'll fix that.

But you should know that behavior under the slow 4K model
tells very little about the true scheduling and placement
quality of the patches... ]

Please report proper THP-enabled numbers before continuing.

Thanks,

Ingo
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