We use HT in AWS when running a large set of single-thread jobs across a cluster. While the individual jobs run more slowly, the total set of jobs completes more quickly, saving us money. Generally HT gets about a 15% speed increase (and corresponding cost savings) over 2x ... in other words 2x the number of jobs will take ~1.85 times as long. Obviously not ideal for a multi-user cluster (users want 'their job' to complete in a predictable amount of time, and never 1.85x as long as usual), but when the $$s count (AWS, etc.) it can be a win.
Cheers, -Hugh -----Original Message----- From: users-boun...@gridengine.org [mailto:users-boun...@gridengine.org] On Behalf Of Manfred Selz Sent: Thursday, March 17, 2016 10:26 AM To: users@gridengine.org Subject: Re: [gridengine users] SoGE: hyperthreading on or off? Hi, I agree with Reuti. My experience also leads to not use HT at all - all of the compute serves in the company I'm working for (including those used as SGE masters) have HT disabled in the BIOS. We have found that this provides the best performance for critical applications (specifically important for those with expensive licenses). Regards, Manfred -----Original Message----- From: users-boun...@gridengine.org [mailto:users-boun...@gridengine.org] On Behalf Of users-requ...@gridengine.org Sent: Donnerstag, 17. März 2016 13:00 To: users@gridengine.org Subject: users Digest, Vol 63, Issue 17 Send users mailing list submissions to users@gridengine.org To subscribe or unsubscribe via the World Wide Web, visit https://gridengine.org/mailman/listinfo/users or, via email, send a message with subject or body 'help' to users-requ...@gridengine.org You can reach the person managing the list at users-ow...@gridengine.org When replying, please edit your Subject line so it is more specific than "Re: Contents of users digest..." Today's Topics: 1. Re: SoGE: hyperthreading on or off? (Reuti) ---------------------------------------------------------------------- Message: 1 Date: Wed, 16 Mar 2016 23:54:14 +0100 From: Reuti <re...@staff.uni-marburg.de> To: "Lane, William" <william.l...@cshs.org> Cc: "users@gridengine.org" <users@gridengine.org> Subject: Re: [gridengine users] SoGE: hyperthreading on or off? Message-ID: <fb202e7a-c890-4c83-bbcf-2dea7005d...@staff.uni-marburg.de> Content-Type: text/plain; charset=us-ascii Hi, Am 15.03.2016 um 20:43 schrieb Lane, William: > I'm just curious about what the current thoughts are WRT hyperthreading. > > I've read at least one article that suggested hyperthreading be left > on so that the OS can take advantage of it, but that hyperthreading > cores should be excluded from being bound to SoGE HPC jobs. Is this > still the best strategy to follow? Or was it ever a good strategy to follow? > > Could excluding hyperthreading cores be accomplished by using the qsub > -binding parameter? Or should SoGE itself be configured to ignore > hyperthreading cores? > > My research into hyperthreaing and HPC has only turned up two strategies: > 1. turn off hyperthreading completely at the BIOS level 2. the above > situation where the OS is still allowed to use hyperthreading but HPC > apps are disallowed binding to hyperthreading cores. I came to the same conclusion, as our applications don't like HT. I don't recall whether it was on the Beowulf or Open MPI list, where someone mentioned that turning HT off in the BIOS will also make some changes to the internal caching and/or handling of the pipeline. But I couldn't see this effect (I would have expected to get only half of the cores but slightly faster). HT may be better suited in case you want to run at least two different jobs on a machine and the access to CPU resources can joggle this way. I mean: using HT for an Open MPI or OpenMP job on a machine will lead to the effect that all forks/threads are doing the same at the same time and need the same resources (at least I would expect it to be this way). But two completely unrelated types of jobs may have better luck to get a benefit of HT. Looking into new machines, there are also several CPUs without HT capability. -- Reuti ------------------------------ _______________________________________________ users mailing list users@gridengine.org https://gridengine.org/mailman/listinfo/users End of users Digest, Vol 63, Issue 17 ************************************* ________________________________ Dialog Semiconductor GmbH Neue Str. 95 D-73230 Kirchheim Managing Directors: Dr. Jalal Bagherli, Carsten Dahl Chairman of the Supervisory Board: Rich Beyer Commercial register: Amtsgericht Stuttgart: HRB 231181 UST-ID-Nr. DE 811121668 Legal Disclaimer: This e-mail communication (and any attachment/s) is confidential and contains proprietary information, some or all of which may be legally privileged. It is intended solely for the use of the individual or entity to which it is addressed. Access to this email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. Please consider the environment before printing this e-mail _______________________________________________ users mailing list users@gridengine.org https://gridengine.org/mailman/listinfo/users _______________________________________________ users mailing list users@gridengine.org https://gridengine.org/mailman/listinfo/users
