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Number crunching :
Multi core support
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Author | Message |
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Send message Joined: 15 Mar 12 Posts: 4 Credit: 100,671 RAC: 0 |
I have an off the wall question. I have an i7-940xm mobile processor overclocked 5%. When I get processes that use the 8 cores I can process 656682 GFLOPS in about 1-2 minutes, but when I am processing the single core versions it takes 3+ hours for only 29640 GFLOPS. Now my question is that when I finish the 656682 GFLOPS I get less than 1 credit most of the time but when I do 29640 GFLOPS I get over 100 credits. That just seems backward to me that when I do more GFLOPS I get less credit since it does not take as long when it uses all 8 of my cores? I hope this makes sence to someone. |
Send message Joined: 8 May 09 Posts: 3315 Credit: 519,943,497 RAC: 22,353 |
I have an off the wall question. I have an i7-940xm mobile processor overclocked 5%. When I get processes that use the 8 cores I can process 656682 GFLOPS in about 1-2 minutes, but when I am processing the single core versions it takes 3+ hours for only 29640 GFLOPS. Now my question is that when I finish the 656682 GFLOPS I get less than 1 credit most of the time but when I do 29640 GFLOPS I get over 100 credits. That just seems backward to me that when I do more GFLOPS I get less credit since it does not take as long when it uses all 8 of my cores? I hope this makes sence to someone. Credits are not based on how long it takes, people with slow computers would get tons of credits and the fast pc would get none in that case. Credits are based on how much WORK your pc does during that time. |
Send message Joined: 18 Jul 09 Posts: 300 Credit: 303,562,776 RAC: 0 |
You are crunching both n-body and separation work units. The n-body WUs take just a few seconds or minutes on your system while the separation WUs take 10,000+ seconds. If you want either one or the other, you can set that in your MW preferences. |
Send message Joined: 1 Sep 08 Posts: 204 Credit: 219,354,537 RAC: 0 |
I don't think these GFLOP number are correct, or at least the amount of credit and computation time you assign are not right. If you look into your profile under "computers belonging to this account" and there on the machine and then "workunits", you'll see that for n-body (all cores) you get about 8 credits per minute, whereas the separation WUs (one core each) take about 10 ks for 160 credits. Overall that's a maximum of ~10300 RAC for separation tasks and 11000 RAC for n-body tasks. That's a nice agreement, actually. However, AMD GPUs (not your's, only some high end models) can crunch these separation WUs within a minute, so you may consider running only n-body on your CPU to contribute efficiently. MrS Scanning for our furry friends since Jan 2002 |
Send message Joined: 15 Mar 12 Posts: 4 Credit: 100,671 RAC: 0 |
Thanks again everyone for helping me out. I'm sorry if I sound stupid or anything I'm just very new to this and don't understand much about it, but thank you all again for helping me. :) |
Send message Joined: 1 Sep 08 Posts: 204 Credit: 219,354,537 RAC: 0 |
No worries, we're here to help! MRS Scanning for our furry friends since Jan 2002 |
Send message Joined: 29 May 10 Posts: 19 Credit: 5,917,319 RAC: 0 |
"However, AMD GPUs (not your's, only some high end models) can crunch these separation WUs within a minute, so you may consider running only n-body on your CPU to contribute efficiently." I have noticed this as well, however I haven't found a way to ONLY have the GPU do separation tasks and the CPU do only n-body simulation tasks. BOINC keeps downloading separation tasks as well as n-body for the CPU, and separation for the GPU. Do you know of a way? |
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