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Number crunching :
Mixture of 32Bit and 64Bit tasks
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Send message Joined: 22 May 14 Posts: 3 Credit: 98,713 RAC: 0 |
Apologies in advance is this is an old question, but why are some tasks 32Bit and some 64Bit ? Is my PC assigned a 'random' selection comprising tasks for both CPU architectures ? If there's an advantage in running 64Bit tasks on a 64Bit PC, is there a way that my account will only get assigned 64Bit tasks? ============ |
Send message Joined: 27 Sep 08 Posts: 817 Credit: 681,978,528 RAC: 141,852 |
As you can see in your screen shot, the exe is called win64 but you can see (32bit) at the end of all of them, all the LHC exe's are 32bit. Since you can get x64 boinc software I think the project have to offer an x64 version even if it's not actually x64. |
Send message Joined: 12 Jul 11 Posts: 857 Credit: 1,619,050 RAC: 0 |
All our executables are 32-bit indeed. We just give them a different name for 64-bit machines. Why? Because we have not (yet) verified the numerical correctness of 64-bit executables. This implies using a 64-bit version of crlibm, and running many many tests. Since the performance is the same (in fact even a bit faster on 32-bit) it is not a priority until other stability issues are solved. While in theory there should be NO numerical differences the sad fact is that different compiler versions are involved and we have had some very bad experience. I am hoping to publish all this "soon" but right now I say hello from the CERN 60th Anniversary Open Days. Eric. |
Send message Joined: 22 May 14 Posts: 3 Credit: 98,713 RAC: 0 |
Thanks Toby - yes, I noticed after posting that they all state (32 bit), and should really have delved into Task Manager a bit more, as you can choose to display the 'Platform' column in the Details tab as below: And thanks very much Eric - it's good to know I'm running Sixtrack in the most optimum format currently available. It might also help if I concentrate on tasks related to 'proton beam stability', and not 'pings from ET', but I'm sure you don't mind a mixture of LHC and SETI ;) Good luck with the 60th anniversary celebrations - I wish I was there, but my kids are way too young to be allowed in. Fortunately there is a local exhibition at Manchester that I will take them too: http://mosi.org.uk/whats-on/collider |
Send message Joined: 12 Jul 11 Posts: 857 Credit: 1,619,050 RAC: 0 |
Hi Toby; the next performance improvement will be AVX support. Colleagues are also working on GPU but that is a major change probably requiring many more particles per WU. Yesterday was great; I was at the LHCb experiment and even managed to go 100m down and see the detector, but not the beam pipe or the tunnel. The weather gods were kind and we had quite a few visitors though not as many as last year for the "Portes Ouvertes". Probably the last chance to visit for quite a few years as the LHC startup should begin in a few months. The DG paid a flying visit. He is a strong believer in outreach but I didn't get a chance to thank him for saving LHC@home when he included it in a presentation at the Frankfurt Book Fair in 2012. Regards. Eric. |
Send message Joined: 27 Sep 08 Posts: 817 Credit: 681,978,528 RAC: 141,852 |
Seems like AVX/2 will give a good boost to the app as it's the sort of calcs that AVX is designed for. I'm sure GPU is a ton of work especially when you think about the mathematical equivalence that you strive for. Sounds great I tried to visit when I was in Switzerland earlier in the year but the tours book up very far in advance I found out! Next time :) |
Send message Joined: 27 Sep 08 Posts: 817 Credit: 681,978,528 RAC: 141,852 |
Ben, every project is happy that you contribute what you can to there efforts. It's up to you to decide which project your involved in and how much you contribute to each one. I've contributed to 10 different project in various amounts :) |
Send message Joined: 22 May 14 Posts: 3 Credit: 98,713 RAC: 0 |
Thanks Toby. I was lucky enough to get a personal tour of the site when I came to visit a work colleague about 5 years ago, but obviously had to stay at the surface level. I bet more people have climbed Everest than visited the detectors ;) The visitor's facilities are excellent anyhow. I was happy enough just looking down the viewing shafts and took loads of photos, but you just can't judge the physical scale looking down: Anyway, I've gone way off topic here ;) |
Send message Joined: 24 Oct 04 Posts: 1155 Credit: 51,752,237 RAC: 47,714 |
Doesn't every member that started here in 2004 with over 980,000 credits get a free trip to Cern and tour of the LHC? Volunteer Mad Scientist For Life |
Send message Joined: 12 Jul 11 Posts: 857 Credit: 1,619,050 RAC: 0 |
Well, as for GPU, the numerical business I am pretty sure I have solved but need to test. If we can fit the main tracking loop into the GPU, which has many smaller loops inside, BINGO. We only need to write the small "checkpoint" data every so many turns back to the host. However right now we have one binary file for every pair of particles, and using a lot of particles (for GPU performance) is impractical. I am a guide, and next time you are in Switzerland, I can show you round but I won't be able to take you 100m underground as the LHC is scheduled for restart. Eric. |
Send message Joined: 27 Sep 08 Posts: 817 Credit: 681,978,528 RAC: 141,852 |
Magic I think the trips are free they're just very popular as you can imagine. |
Send message Joined: 27 Sep 08 Posts: 817 Credit: 681,978,528 RAC: 141,852 |
Sounds like you need a lot of refactoring in the code to support the GPU, now you can run OpenCL on Intel GPU's too, that should bring a lot of extra computing power to the project. I have my GTX titan ready for the project. |
Send message Joined: 24 Oct 04 Posts: 1155 Credit: 51,752,237 RAC: 47,714 |
Actually what I was hoping for Toby is a free flight for 2 (have to bring the wife) from Seattle and free hotel.....ok it was just a dream But of course I would want the tour by Eric so maybe you can get that free vacation too ! Volunteer Mad Scientist For Life |
Send message Joined: 27 Sep 08 Posts: 817 Credit: 681,978,528 RAC: 141,852 |
That would be the best BOINC reward I every heard of :) |
Send message Joined: 24 Oct 04 Posts: 1155 Credit: 51,752,237 RAC: 47,714 |
That would be the best BOINC reward I every heard of :) Yes it would be better than an Einstein Certificate from the Max Planck (ok don't tell anyone I said that ) But it does seem fair to me since I have been doing this daily since the Seti Classic days in 1999.........man I am getting to be an old timer. Then Eric could let me pick another Boinc member to make that trip so that would have to be you since we both started over at T4T basically the same day and are here every day.........man hard to believe I have been on this project for 10 years now And you have more hosts here than I do since mine are all GPU mad scientists @ the Einstein project. You know you have to be interested in the LHC when we do this for hardly any of those *credits* (compared to those BRP PAS- GPU tasks) Volunteer Mad Scientist For Life |
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