[CentOS] HT (Hyper Threading) on CentOS 5.5

Fri Mar 9 08:05:15 UTC 2012
Sorin Srbu <sorin.srbu at orgfarm.uu.se>

-----Original Message-----
From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On Behalf
Of John R Pierce
Sent: den 9 mars 2012 08:54
To: centos at centos.org
Subject: Re: [CentOS] HT (Hyper Threading) on CentOS 5.5

On 03/08/12 11:44 PM, Sorin Srbu wrote:
> I know there might be some negative performance issues with certain
> applications, but would you notice it in day-to-day use?

if you're using the server for pure floating point compute, don't run 
more threads than you have actual cores.   high concurrency server 
workloads that aren't IO bound generally benefit quite a lot from using 
hyperthreads to double the number of active workers.   the HT on the 
X5600 and such newer Xeons is quite a lot better than the old 
netburst/p4 architecture where the benefits were marginal in many cases.