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Hi,<br><br>These are nehalem Xeons I presume?<br>Then you get 15 to 20% more performance in Gromacs running 2 vs 1 thread or process per physical core.<br><br>Berk<br><br>> Date: Fri, 6 Aug 2010 09:24:11 -0500<br>> From: dmobley@gmail.com<br>> To: gmx-users@gromacs.org<br>> Subject: [gmx-users] hyperthreading<br>> <br>> Dear All,<br>> <br>> I'm putting together a new Dell Xeon cluster running ROCKS 5.3 which<br>> uses CENTOS (6 I believe). This is currently ~20 dual quad-cores with<br>> roughly 16 GB of RAM each.<br>> <br>> In any case, I wanted to inquire about hyperthreading. Does anyone<br>> have experience on similar machines with vs. without hyperthreading?<br>> The ROCKS users list suggests that hyperthreading ought always be off<br>> for HPC applications, which sounds overly simplistic to me, though I<br>> more or less follow the logic of this.<br>> <br>> So, has anyone done any benchmarking yet in a similar setting, and<br>> what thoughts do you have? I obviously can do some benchmarking myself<br>> as well but I thought I'd check in with the list first.<br>> <br>> Thanks so much,<br>> David<br>> <br>> <br>> -- <br>> David Mobley<br>> dmobley@gmail.com<br>> 504-383-3662<br>> -- <br>> gmx-users mailing list gmx-users@gromacs.org<br>> http://lists.gromacs.org/mailman/listinfo/gmx-users<br>> Please search the archive at http://www.gromacs.org/search before posting!<br>> Please don't post (un)subscribe requests to the list. Use the <br>> www interface or send it to gmx-users-request@gromacs.org.<br>> Can't post? Read http://www.gromacs.org/mailing_lists/users.php<br>                                            </body>
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