I must have missed where you describe exactly what tasks you are submitting.
If you submit multiple CPU-intensive tasks then you should see multiple cores go to high percent used. But if your tasks are I/O bound then the CPU % will not hit 100% as the process block for I/O. Showing 100% CPU may or may not be a good thing. If your tasks were inefficiently programmed they might be CPU bound and possibly some optimization thereafter might overcome that dependency and lead to an I/O bound condition. From: Wil Irwin [mailto:[email protected]] Sent: Thursday, April 05, 2012 1:24 PM To: zxq9 Cc: Scientific Linux Users List Subject: Re: Multiple terminal windows won't send jobs to individual cores Thanks for all of the suggestions. To recap: 1. I'm not sure why my claim that running jobs in several terminal windows will "automatically" be distributed to the next least used core (and it will run at 100% until the job is done. I have be doing this for years w/o ANY special coding or using any task managers or scheduler. Not only does (or did) work on SL, but I use this same strategy on an an Ubuntu installation (a virtual Ubuntu running on a Windows machine, to boot!). 2. I am more than willing to look into task managers/schedulers, but I shouldn't need to go down that road. 3. The fact that the tar extraction process is so slow as to be effectively useless, suggest something of a larger problem. 4. These problems exist on 3 machines which are IDENTICAL in every respect and the hardware is less than 1 year old. 5. I will investigate possible BIOS issues; I don't thing dirty power is an issue as the machines are on UPS which provides some degree of power conditioning. And, these units have been in place (about 6 months old) and were in place when things were running "correctly". 6. The only "hopeful" aspect in this very confusing, annoying and frustrating situation is that the behavior is identical on all 3 machines. I welcome other suggestions for troubleshooting. I am hoping I can post a solution to this dilemma in the near future-- my work has come to a screeching halt. Regards, Wil On Thu, Apr 5, 2012 at 11:59 AM, zxq9 <[email protected]<mailto:[email protected]>> wrote: On 04/06/2012 03:18 AM, Stephen John Smoogen wrote: On 5 April 2012 10:47, Wil Irwin<[email protected]<mailto:[email protected]>> wrote: Hi- I am totally stumped and at a complete loss on this one. In an 'old school' manner (a.k.a poor man's grid engine), it is a common practice (at least for me) to open multiple terminal windows on a mullti-core machine. Submitting a job in each terminal window will send it to a core which is not being used. On this particular set of machines I have been doing this for about 2 years. To be honest I have no idea why it worked before. Setting a process to a certain core takes definitive coding to say "x will have affinity to CPU y" or using a program like taskset to set the affinity. I would try the following: 1) man taskset 2) see if taskset works on your system. Then see if it works. If it doesn't then I would assume that the CPU or some other hardware in the box is having issues and not allowing processes on the other cores for some reason. In addition to the excellent advice here, I've seen a very similar problem before with some faulty BIOS code telling the system to kick in to a very conservative processing mode when certain voltage indicators were met. This came out of the blue and was extremely frustrating to troubleshoot because it like what you're seeing but was a hardware issue born of a special combination of dirty power input, a slowly fading PSU and a cranky mainboard. The odds of that ever happening again anywhere are probably pretty low, especially with server type boards, but its worth considering. Good luck finding your solution. That must be annoying. -z
