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World Community Grid Forums
Category: Retired Forums
Forum: The New Members Forum [Read Only]
Thread: Warning for Slashdot Users: UDTweaker |
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Thread Status: Active Total posts in this thread: 2
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Unfortunately, the Slashdot post includes a link to UDTweaker. I had better point out this post, made on 10 Dec 2004 by gbo2.
----------------------------------------gbo2 10 Dec 2004 UD Tweaker does NOT work!! Second page of thread. http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=201#4086 The forum software does not take you straight to the post. For some reason if a thread has more than 20 posts, it just dumps you at the start of the thread (or a different way gets you within 20 posts of the correct post). So I am going to copy the post here: Well i know there was a program called UDTweaker for the UD client. I don't know if it works with this client? UDTweaker is at http://blakenyc77.tripod.com/udtweaker.html and will probably work, because the WCG and UD Agent are very similar. I hate to be the bearer of bad news, but if you follow the link on the UD Tweaker website to the grid.org forums, you will find that United Devices -- who makes the software for that grid project and this one (they're virtually identical -- a few thousandths of a version number -- and I've run Rosetta from both) -- does not recommend UD Tweaker because A) It corrupts results and B) It is not necessary if you are just using hyper threading. Supposedly if you read the whole thing UD says that UD Tweaker uses an unsupported switch in the program that never was fully debugged. You end up returning results (and possibly getting points) but they will be corrupted and you will have accomplished nothing. The reason you don't need UD Tweaker on a hyper threaded pentium 4 is that there is really only one CPU with one floating point processor, but the operating system is tricked into seeing 2 processors. So even though you only see 50% utilization you are really hitting the FPU at 100%. By using UD tweaker you see 100% utilization, but what is really happening is that instead of processing 1 work unit at 100%, you are now processing two work units at 50%. This is less efficient and it would run faster if you didn't run UD Tweaker. This is all according to UD and I have to think that they would have endorsed UD Tweaker if it worked or at least given silent approval. It certainly seems that no one at grid.org is using UD Tweaker. That said, I do think that United Devices should get their heads out of the sand and finally write a program that can handle multiple processors and run on linux and macs. Read it for yourself here: http://forum.grid.org/phpBB/viewtopic.php?t=4624 I think I will add some more threads: running WCG Agent as a service http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=767 http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=217#1190 UD Monitor Rick Alther http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=1108#5103 http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=478 jbabco 18 Nov 2004 ThreadMaster http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=184 joatmon 3 Dec 2004 on Setting Time Zones, etc. http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=834 Rick Alther 8 Dec 2004 on Check Points and Killing Rosetta http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=892 McAfee 8.0 Problems http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=347#3130 http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=753#3129 Here is a post that I made for a new member several days ago: http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=1144#5352 [Edit 1 times, last edit by Former Member at Dec 31, 2004 6:30:36 AM] |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
I don't know much about TD Tweaker, but if it does cause data corruption, then it shouldn't be used.
The basic theory behind HT is that there is sometimes latency when executing instructions because the processor has to wait for data to be loaded from ram into the cache. Some programs benefit a lot from HT, some don't. A lot of factors go into it, and it depends on the program. There can be a big improvement because while the processor is waiting while loading from memory into cache, it will execute the other thread's instructions insted of being idle, and this can cause a big improvement. All programs have these delays, the question is how often these delays occur. Or not... If the program doesn't often have delays to load the cache from ram (if it's properly optimized), the overhead of switching between the treads will actually decrease preformance. Also HT doesn't help out the FPU (Floating Point Unit). While using the FPU is usually a bad idea (but not always), programs that make heavy use of it won't be helped out by HT much. But, if you have HT enabled already, and you are only running one instance, don't worry even though you're showing 100% usage on one processor, and 0% on the other. Part of HT is that it swiches back and forth to try to find instructions to execute. If there aren't any instructions to execute on one "processor" then the other one will recieve full power. Easiest way is to do a simple benchmark. It takes my P4 3.0 w/ 1gig ram about 13hours to complete a work unit. If you're only running at half power, yours would take 26hours to execute 1 unit. Corrupted data is more then worthless to the project, because they can't tell if the data is corrupt, so they have to realize that your data is incorrect, then recalculate it. I would wait for one of the developers to say if they feel it's safe. I think the two installation method would be safe, but I don't know, I can imagine situations where it wouldn't be. HT can provide a mild improvement (10-20% maybe) but it's not worth it unless you're sure you're returning good results, and that's the most important thing. So I wouldn't mess with it until the developers mess with it enought to be able to say one way or the other. For those of you with dual processors, I would put world grid on one processor, and another project on the other. Kunnis |
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