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World Community Grid Forums
Category: Completed Research
Forum: Help Conquer Cancer
Thread: Can a WU use more than 50% on a Pentium4 HT CPU? |
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Thread Status: Active Total posts in this thread: 6
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Perhaps someone can help shed some light on this.
Just started using a Dell Optiplex GX620 USFF system, having always used AMD PCs this is my first computer which has HyperThreading Technology. However, I had to set Boinc to 50% of CPUs, thus, limiting to 1 WU at a time as the PC was sluggish when trying to crunch two WUs. Yet in Task Manager I notice that Help Conquer Cancer (wcg_hcc1_img_6.06_windows_intelx86) is using as much as 80% of the available CPU. Is this normal for HCC or HyperThreading? |
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Sekerob
Ace Cruncher Joined: Jul 24, 2005 Post Count: 20043 Status: Offline |
Hi,
----------------------------------------Unless you've set the throttle too, I'd expect for any job to use 100% of the spare time i.e. if you use 20%, the science uses the 80% left. If you have the Use at most xxx.xx% CPU time set, then you'll see the used CPU time go up and down in kind of an on/off type alternation. Not sure if when having BOINC is allowed 1 core with hyperthreading still on if it uses the physical or virtual core, nor whether tasksmanager will read out each core from 0 to 50% or 0 to 100%. In windows on my duo and quad the % use is pro-rata i.e. on a duo TM reads out a max of 50% ( = 100% of 1 core)
WCG
Please help to make the Forums an enjoyable experience for All! |
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JmBoullier
Former Community Advisor Normandy - France Joined: Jan 26, 2007 Post Count: 3716 Status: Offline Project Badges: 
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Yet in Task Manager I notice that Help Conquer Cancer (wcg_hcc1_img_6.06_windows_intelx86) is using as much as 80% of the available CPU. Is this normal for HCC or HyperThreading? 80 % is surprising. In my P4 HT under XP I have never seen TaskManager reporting more than 50 % for any single process. If I suspend one of the two tasks it is normally running the remaining active one is showing 50 % and the "unused" percents are allocated to the "Idle System Process".That makes me wonder if HT might have been de-activated in your machine. Have you got it from somebody else or have you set it up yourself? If HT is off that could also explain why the machine is sluggish when you try to run two tasks. |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Looks like a reboot fixed the problem. Hyper-Threading is enabled by-default in the Dell bios and it does show two "CPU Usage History" windows in Task Manager. Just hoping it doesn't affect the end result.
Thanks for the replies. |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
I had a P4 HT 3.0 Ghz and you can avoid lag by using 100% of CPU but 99% of CPU time (throtle), that 1% made all the difference for me, I could do anything with out any lag. Intel PERL MoBo & DDR-400 4x 512 MB Dual-channel (you only need 2x 512 MB or 2x 1 GB for dual channel).
----------------------------------------[Edit 1 times, last edit by Former Member at May 21, 2010 11:56:09 AM] |
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Sekerob
Ace Cruncher Joined: Jul 24, 2005 Post Count: 20043 Status: Offline |
The 99% on CPU Time setting means running 99 seconds, pausing 1 second [it's designed as a thermal control]. No idea how that can make a perceptual difference on the lag experience. However, if 99% of CPU was set and 100% of time, the real was only 1 thread run by BOINC since the use of processor is rounded down to the nearest whole thread/core. i.e. on a 4 core system entering 99% will use only 3 cores. Somewhere in the FAQs I put a table what the effects of different percentage on different number of cores is.
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WCG
Please help to make the Forums an enjoyable experience for All! |
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