Re: Turn off Hyperthreading! WAS: 60 core performance with 9.3

On 2014-08-21 14:02:26 -0700, Josh Berkus wrote:
> On 08/20/2014 07:40 PM, Bruce Momjian wrote:
> > Not sure how you can make such a blanket statement when so many people
> > have tested and shown the benefits of hyper-threading.
>
> Actually, I don't know that anyone has posted the benefits of HT.
> Link?

There's definitely cases where it can help. But it's highly workload
*and* hardware dependent.

> OS is RHEL with 2.6.32-431.3.1.el6.x86_64.
>
> I've emailed a kernel hacker who works at Intel for comment; for one
> thing, I'm wondering if the older kernel version is a problem for a
> system like this.

I'm not sure if it has been backported by redhat, but there
definitely have been significant improvement in SMT aware scheduling
after vanilla 2.6.32.

Greetings,

Andres Freund

--
 Andres Freund                       http://www.2ndQuadrant.com/
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