Re: [PERFORM] hyperthreadin low performance

2015-07-21 Thread David Rowley
On 21 July 2015 at 14:59, Jeison Bedoya Delgado jeis...@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.6050...@agliodbs.com

Regards

David Rowley

--
 David Rowley   http://www.2ndQuadrant.com/
http://www.2ndquadrant.com/
 PostgreSQL Development, 24x7 Support, Training  Services


Re: [PERFORM] hyperthreadin low performance

2015-07-21 Thread Mark Kirkwood

On 21/07/15 20:04, David Rowley wrote:

On 21 July 2015 at 14:59, Jeison Bedoya Delgado
jeis...@audifarma.com.co mailto:jeis...@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.6050...@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@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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