Messages in this thread | | | Date | Tue, 29 Jun 2004 01:24:52 +1000 | From | Con Kolivas <> | Subject | Re: Nice 19 process still gets some CPU |
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Timothy Miller wrote: | | | Con Kolivas wrote: | |> |> It definitely should _not_ starve. That is the unixy way of doing |> things. Everything must go forward. Around 5% cpu for nice 19 sounds |> just right. If you want scheduling only when there's spare cpu cycles |> you need a sched batch(idle) implementation. |> |> | | Well, since I can't rewrite the app, I can't make it sched batch. Nice | values are an easy thing to get at for anything that's running. | | Besides, comparing nice 0 to nice 19, I'd expect something more like a | 100:1 ratio or worse. (That is, I don't expect nice to be linear.) | | Maybe this is just me, but when I set a process to the worst possible | priority (nice 19), I expect it only to run when nothing else needs the | CPU.
Sched batch is a kernel modification, and a simple wrapper will allow you to run _any_ program as sched batch without modifying it's source.
The design has had that ratio of 20:1 for a very long time so now is not the time to suddenly decide it should be different. However if you want to make it 100:1 for your machine feel free to edit kernel/sched.c and change #define MIN_TIMESLICE ( 10 * HZ / 1000) to #define MIN_TIMESLICE ( 1 * HZ / 1000)
That will give you more what you're looking for.
Con -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org
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