Re: HT on or off for E5-26xx ?

Hi,

On Tue, 2012-11-06 at 20:31 -0700, David Boreham wrote:

> Was assuming it was 6-core but I just noticed it has HT which is
> currently enabled since I see 12 cores in /proc/cpuinfo
>
> Question for the performance experts : is it better to have H enabled
> or disabled for this generation of Xeon ? Workload will be moderately
> concurrent, small OLTP type transactions. We'll also run a few
> low-load VMs (using KVM) and big Java application.

HT should be good for file servers, or say many of the app servers, or
small web/mail servers. PostgreSQL relies on the CPU power, and since
the HT CPUs don't have the same power as the original CPU, when OS
submits a job to that particular HTed CPU, query will run significantly
slow. To avoid issues, I would suggest you to turn HT off on all
PostgreSQL servers. If you can throw some more money, another 6-core CPU
would give more benefit.

Regards,

--
Devrim GÜNDÜZ
Principal Systems Engineer @ EnterpriseDB: http://www.enterprisedb.com
PostgreSQL Danışmanı/Consultant, Red Hat Certified Engineer
Community: devrim~PostgreSQL.org, devrim.gunduz~linux.org.tr
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