Date: Sun, 20 Nov 2011 17:41:32 -0500 From: Stephen Reese <rsreese@...il.com> To: john-users@...ts.openwall.com Subject: Re: OpenMP not using all threads On Sun, Nov 20, 2011 at 5:21 PM, Stephen John Smoogen <smooge@...il.com> wrote: > On 19 November 2011 21:35, Stephen Reese <rsreese@...il.com> wrote: >> On Sat, Nov 19, 2011 at 11:13 PM, Solar Designer <solar@...nwall.com> wrote: >>> On Sat, Nov 19, 2011 at 10:38:30PM -0500, Stephen Reese wrote: > >> I confirmed that there are 8 threads (4 cores) in the processor >> http://ark.intel.com/products/40201/Intel-Xeon-Processor-L5520-%288M-Cache-2_26-GHz-5_86-GTs-Intel-QPI%29 >> I asked Linode and their response was there are four cores hence I am >> only going to see four entries in /proc/cpuinfo. Maybe they have >> hyper-threading disabled (I asked and did not receive a specific >> response). > > Most (if not all) Linode systems are virtualized systems which I > believe normally don't do well with hyperthreading. For high compute > virtualization you usually need systems with cpu-pinning and such to > get the performance that you get from bare metal. > > -- > Stephen J Smoogen. > "The core skill of innovators is error recovery, not failure avoidance." > Randy Nelson, President of Pixar University. > "Let us be kind, one to another, for most of us are fighting a hard > battle." -- Ian MacLaren > Stephen, You are correct but running separate instances verse OpenMP seems to be doing pretty well.
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