Finding Bottlenecks

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cudiatail12

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Message 103985 - Posted: 17 Apr 2021, 6:11:56 UTC
Last modified: 17 Apr 2021, 6:21:05 UTC

I have been crunching for Rosetta@Home. On one host, real-time and CPU time are almost the same, but real-time is 1.5 to 2 times higher than the CPU time for another host. The host with the real-time longer has a better CPU and faster memory. Both BOINC directories are on SSDs. I cannot think what the bottleneck is.
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Bryn Mawr
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Message 103986 - Posted: 17 Apr 2021, 7:15:36 UTC - in response to Message 103985.  

I have been crunching for Rosetta@Home. On one host, real-time and CPU time are almost the same, but real-time is 1.5 to 2 times higher than the CPU time for another host. The host with the real-time longer has a better CPU and faster memory. Both BOINC directories are on SSDs. I cannot think what the bottleneck is.


What operation system are you using?

The symptom you are experiencing is due to the computer doing other work alongside Boinc. Go into task manager / system monitor and see what else is taking CPU time - very possibly a background task such as file indexing, Windows update, antivirus scan, etc.
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Richard Haselgrove
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Message 103987 - Posted: 17 Apr 2021, 8:50:44 UTC

Another possible explanation is that your 'better CPU' - the one with the time differential - is using a technology called 'hyperthreading'. This enables one physical CPU 'core' to work on two different computer programs at once.

When the two programs are different, they might use different resources, or have pauses when, for example, they're waiting for you to press the next key on the keyboard. Under these circumstances, a hyperthreaded core can feel almost as fast as two completely separate cores.

But when the two running programs are similar - say, two Rosetta tasks - and both use the same parts of the CPU hardware, they are competing rather than collaborating, and get in each other's way. There aren't so many gaps available, and overall progress doesn't increase so much. In general, hyperthreading (or HT) isn't as much use on BOINC projects as it is in other areas of computing.
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Profile Joseph Stateson
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Message 103988 - Posted: 17 Apr 2021, 14:45:29 UTC - in response to Message 103985.  
Last modified: 17 Apr 2021, 15:11:10 UTC

I have been crunching for Rosetta@Home. On one host, real-time and CPU time are almost the same, but real-time is 1.5 to 2 times higher than the CPU time for another host. The host with the real-time longer has a better CPU and faster memory. Both BOINC directories are on SSDs. I cannot think what the bottleneck is.



According to this thread, the real time should be about the same. I do not run Rosetta anymore so I cannot check the validity of that post (dated April fools day) but I did check the real time of some leaders and they were all in the 8 hour range Irregardless of the CPU speed.

[edit] I looked for your computers over at Rosetta but could not find you. I suspect, that if both of your systems are finishing the jobs in about 8 hours then all is ok.
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cudiatail12

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Message 104001 - Posted: 17 Apr 2021, 19:34:04 UTC

All of you have given me something to think about. Both CPUs have hyperthreading enabled on Windows OSs. I will look into background processes on the hosts.
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ProDigit

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Message 104066 - Posted: 22 Apr 2021, 21:13:48 UTC

Hardware info?
Like what CPU, what RAM speeds, etc..
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Message boards : Questions and problems : Finding Bottlenecks

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