Re: hyperthreadin low performance

is the problem also in PostgreSQL 9.4.x?
I'm going to buy a production's server with 4 sockets E7-4850 12 cores
so 12*4 = 48 cores (and 96 threads using HT).

What do you suggest?
Using or not HT?

BR
Domenico

2015-07-21 11:07 GMT+02:00 Mark Kirkwood <mark.kirkwood@catalyst.net.nz>:
> On 21/07/15 20:04, David Rowley wrote:
>>
>> On 21 July 2015 at 14:59, Jeison Bedoya Delgado
>> <jeisonb@audifarma.com.co <mailto:jeisonb@audifarma.com.co>> wrote:
>>
>>     hi everyone,
>>
>>     Recently update a database to machine with RHEL7, but i see that the
>>     performance is betther if the hyperthreading tecnology is
>>     deactivated and use only 32 cores.
>>
>>     is normal that the machine performance is better with 32 cores that
>>     64 cores?.
>>
>>
>> You might be interested in
>> http://www.postgresql.org/message-id/53F4F36E.6050003@agliodbs.com
>>
>
> However I do wonder if we have been misinterpreting these tests. We tend to
> assume the position of "see hyperthreading is bad, switch it off".
>
> The linked post under the one above:
>
> http://www.postgresql.org/message-id/53ED371D.109@catalyst.net.nz
>
> shows that 60 core (no hyperthreading) performance is also pessimal, leading
> me to conclude that *perhaps* it is simply the number of cores that is the
> problem - particularly as benchmark results for single socket cpus clearly
> show hyperthreading helps performance...
>
> Regards
>
> Mark
>
>
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