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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Hello again!
Today while I was on XtremeSystems, someone mentioned that they noticed a direct correlation between the successful cache and the efficiency of that cpu on that particular project, and it got me thinking about how we could improve the efficiency of the grid: Since each of the projects requires a different amount of memory, it follows that each requires a different amount of cache (as all excess will go to main memory). Since Boinc already knows the cpu model number, and therefore the cache size, would it not be efficient to favor sending projects to cpus that can successfully cache large amounts of the programming instructions? I realize I may not be making this as clear as I had hoped, so here’s an example that I hope clears it up. As BlindFreddie said over at XS: On a CPU-A, FAAH’s cache success is over 96%, but on the CPU-B (512KB cache/core) this drops to 85% Because of this, CPU-A finishes the unit more efficiently as there less clock cycles left idle because less calls are made to main memory (which can take 100’s of cycles to report). So wouldn’t it be more efficient to give CPU-A the FAAH units and CPU-B something less cache intensive unless specified by the user? It could be left that a mix is still given out, as probably would be the case because of what is available in the hopper, but then weight it toward the projects that any particular CPU is most apt for (or allow the user to chose whether to receive a mix or most suitable) Just a thought. If there is any flaw in that please let me know! Otis11 *Note: These are real CPUs running right now, but as they are different brands, they were labled A and B to remove any brand bias |
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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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I'll leave it to the techs to give you an authorized answer, but I already have two questions.
----------------------------------------1. What makes you think that BOINC knows the specs of all processors participating to grid computing? 2. Why do you think that what is true for FAAH is not true for all other projects? I think that all applications need more memory than the cache size allocated to a single core, therefore all should benefit from the largest cache. ---------------------------------------- [Edit 1 times, last edit by JmBoullier at Nov 25, 2009 5:21:46 AM] |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
I'll leave it to the techs to give you an authorized answer, but I already have two questions. 1. What makes you think that BOINC knows the specs of all processors participating to grid computing? 2. Why do you think that what is true for FAAH is not true for all other projects? I think that all applications need more memory than the cache size allocated to a single core, therefore all should benefit from the largest cache. Thanks for the quick reply! And as for your questions, I could be wrong, but i believe 1. Since when Boinc runs its benchmarks, it has 11/25/2009 3:21:50 AM||Processor: 2 GenuineIntel Intel(R) Core(TM)2 Duo CPU P7350 @ 2.00GHz [Intel64 Family 6 Model 23 Stepping 6] 11/25/2009 3:21:50 AM||Processor features: fpu tsc pae nx sse sse2 pni it knows my CPU model number (which is not CPU-A nor CPU-B, just what I'm currently on), and there is a specific size of cache for it. So wouldn't it follow that it could easily find out how much cache there is? 2. While i'm sure they all do better with more memory, FAAH may cache 96% while NRW caches 100% on CPU-A(Don't quote me on that, it's only an example) In this case it would probably be a better idea to give FAAH to CPU-A and NRW to CPU-B where it could cache say 92%. Even though neither will get the full unit cached, it's better to have as much as possible cached than have some extra cache on one and not enough on another. Thanks again for your time. |
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Sekerob
Ace Cruncher Joined: Jul 24, 2005 Post Count: 20043 Status: Offline |
For there to be CPU matching, server side with HCMD2 already quite expanded, there have to be groups created and the finer the groups, the unhappier the techs become [it being a manual exercise to populate the group tables and assigning CPU's]. On top the more CPU groups the slower results will move through the system, eventually to a point that validation grinds to a halt.
----------------------------------------Then, let's not talk about the highly arbitrary... "oh you're a CPU-B, you're not getting an FAAH from me"... or am I misunderstanding? Sorry but anyone who's got for instance the right version of WinLuxMac will get anything he/she likes to crunch at the project weights WCG hands results out... up until type A of DDDT-2 as those will have to have oodles of internet bandwidth. As always, something will have got lost in translation. ![]() PS: WCG techs are working on assigning heavy jobs to heavy gear, so something is coming, next year... see posts by knreed.
WCG
----------------------------------------Please help to make the Forums an enjoyable experience for All! [Edit 1 times, last edit by Sekerob at Nov 25, 2009 4:32:52 PM] |
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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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Otis11,
----------------------------------------If the processor's microcode has been designed to answer the cache size question it will, as for the processor features which are currently activated. But while the software needs to know which features it may use it is less obvious that it needs to know the cache size too. But maybe this information is available too, I don't know. Something more useful in my opinion (at least for the servers when trying to evaluate overclaiming) would be the actual clockspeed. But apparently BOINC does not know about it. Personally, when a new project starts I test it on my 3 devices and I see how well it behaves. And if I am not happy with some application/device combo I simply never select this project for that device. I find it simpler and more reliable than leaving it to the servers, even if they were designed to do their best on this topic. No problem with discussing possible improvements with you. Cheers. Jean. |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Something more useful in my opinion (at least for the servers when trying to evaluate overclaiming) would be the actual clockspeed. But apparently BOINC does not know about it. Personally, when a new project starts I test it on my 3 devices and I see how well it behaves. And if I am not happy with some application/device combo I simply never select this project for that device. I find it simpler and more reliable than leaving it to the servers, even if they were designed to do their best on this topic. No problem with discussing possible improvements with you. Cheers. Jean. Well, thanks for your willingness to discuss this! And just to address your 'over-claiming' comment, the points don't really matter to me. I just want to get as much work done as fast and efficiently as possible! And while I realize that it is quite easy for us 'addicts' (well, at least I'm addicted... ) to manually tune our hardware and find which projects are best for which computers, I'm looking at this from the others point of view. The majority of the grid (in my head anyway) are 'set and forget' users. They install Boinc and never look at the project again, except to see how far they have come every once and a while. Nothing against that! - but if we can get more work out of their computers then all the better! Just trying to brainstorm the best way to do this.And to sekerob's comments - Do the CPUs currently have to be matched? I was under the impression that they could just send the WU to whatever CPU requested work and met the minimum requirement for that project...? Also, what do the techs manually have to add? If it's just updating the list when new CPUs come out, that would not be to difficult or time consuming... Even some volunteers could do it if we were asked. Or at least we could gather the data and post it for quick overview and input by the techs later. (Along with the computers, you also have a vast resource of very willing volunteers, let us not forget that!) Then to your concern about people not being able to get the tasks they want... I was not trying to suggest that at all. This is all run by volunteers who in my mind have the power to crunch whatever they so desire, I applaud them for joining! I was just suggesting that if there are multiple checks selected, to set the servers to distribute the work as efficiently as possible. Some others on the XS forum have suggested making a check box similar to the 'receive work from other projects' option. Kinda like a 'request work best for my system first' option. That is also kinda inline with my suggestion if that appears to be better to satisfy the masses? As always, thanks for your time! |
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