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World Community Grid Forums
Category: Community
Forum: Hardware Chat Room
Thread: Is running single project better for performance? |
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Thread Status: Active Total posts in this thread: 5
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sergeid
Cruncher USA Joined: Dec 1, 2005 Post Count: 11 Status: Offline Project Badges: 
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Is running single WCG project on all cores/thread better for performance (I'd imagine better use of cache) comparing to running multiple projects or it doesn't matter much?
Also, is hyper threading really beneficial, considering that two concurrent virtual threads are competing for the same physical core? |
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SekeRob
Master Cruncher Joined: Jan 7, 2013 Post Count: 2741 Status: Offline |
Very unlikely, in fact more probably the opposite.
HT usually gives 15-20 percent uplift in throughput, for maybe the exception of MIP1. I do not allow it to run on more than half of the processor threads (see app_config.xml mentioning posts on how to do this) |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
I agree that MIP1 seems to slow up if it's using too many threads, but I'm not aware of any situations where HT doesn't improve throughput. Having two instruction decode units per execution unit means that if there is a cache miss or branch prediction failure the other thread can usually continue to execute, resulting in far fewer stalls. HT wouldn't still be being designed into chips if it didn't speed things up!
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SekeRob
Master Cruncher Joined: Jan 7, 2013 Post Count: 2741 Status: Offline |
If HT 'usually' gives the said gain, then I fail to see the logic to no not design it in.
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KLiK
Master Cruncher Croatia Joined: Nov 13, 2006 Post Count: 3108 Status: Offline Project Badges: 
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Very unlikely, in fact more probably the opposite. HT usually gives 15-20 percent uplift in throughput, for maybe the exception of MIP1. I do not allow it to run on more than half of the processor threads (see app_config.xml mentioning posts on how to do this) Thanks for the info about the MIP1.  ---------------------------------------- [Edit 1 times, last edit by KLiK at Nov 26, 2017 10:59:16 AM] |
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