| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Rick Otten <rottenwindfish(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Queries intermittently slow |
| Date: | 2016-01-07 19:47:59 |
| Message-ID: | 20160107194759.GM7650@awork2.anarazel.de |
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| Lists: | pgsql-performance |
On 2016-01-07 13:34:51 -0500, Tom Lane wrote:
> It's fairly well established that the implementation of transparent
> huge pages in Linux kernels from the 2.6-or-so era sucks, and you're
> best off turning it off if you care about consistency of performance.
I think the feature wasn't introduced in original 2.6 kernels (3.2 or
so?), but red hat had backported it to their 2.6.32 kernel.
> I am not sure whether modern kernels have improved this area.
I think the problem has largely been solved around 3.16. Around 4.1 I
could still reproduce problems, but the regressions were only in the
sub 10% range in my test workload.
Andres
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