| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org, Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz>, "Graeme B(dot) Bell" <grb(at)skogoglandskap(dot)no> |
| Subject: | Re: Turn off Hyperthreading! WAS: 60 core performance with 9.3 |
| Date: | 2014-08-21 02:40:36 |
| Message-ID: | 20140821024036.GB26706@momjian.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On Wed, Aug 20, 2014 at 12:13:50PM -0700, Josh Berkus wrote:
> On a read-write test, it's 10% faster with HT off as well.
>
> Further, from their production machine we've seen that having HT on
> causes the machine to slow down by 5X whenever you get more than 40
> cores (as in 100% of real cores or 50% of HT cores) worth of activity.
>
> So we're definitely back to "If you're using PostgreSQL, turn off
> Hyperthreading".
Not sure how you can make such a blanket statement when so many people
have tested and shown the benefits of hyper-threading. I am also
unclear exactly what you tested, as I didn't see it mentioned in the
email --- CPU type, CPU count, and operating system would be the minimal
information required.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
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