On Sun, 14 Jun 2009 06:07:16 +0000 (UTC) Jason Lynch <ja...@calindora.com> wrote:
> Thus, I have five processes, four at nice 19, one at nice 0, a load > average of just over 5, but only 3 out of the 4 cores are actually doing > anything. That's an interesting observation with quite a trivial scenario. So I thought to check it out and ran 8 niced copies "while True: pass" script on 8-core machine, atop showed 799-800% load, 100% for each core. Ninth, non-niced process indeed drops the load to 700-710%, with one core absolutely free. Then, I've tried to remove nice form the equation and load held at 800% with 8, 9, 10 and more processes. Nice-only processes behave similary, loading all eight cores. So I guess the problem (or feature?) is related to nice / non-nice processes' scheduling and exists at least in 2.6.29 kernel. Gotta google it a bit later, bet someone on lkml should've noticed it. -- Mike Kazantsev // fraggod.net
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