Messages in this thread | | | From | (bill davidsen) | Subject | Re: Linux 2.6.0-test6 | Date | 1 Oct 2003 21:13:54 GMT |
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In article <3F78D866.5070605@cyberone.com.au>, Nick Piggin <piggin@cyberone.com.au> wrote: | | | bill davidsen wrote: | | >In article <3F77BB2C.7030402@cyberone.com.au>, | >Nick Piggin <piggin@cyberone.com.au> wrote: | > | >| AFAIK, Con's scheduler doesn't change the nice implementation at all. | >| Possibly some of his changes amplify its problems, or, more likely they | >| remove most other scheduler problems leaving this one noticable. | >| | >| If X is running at -20, and xmms at +19, xmms is supposed to still get | >| 5% of the CPU. Should be enough to run fine. Unfortunately this is | >| achieved by giving X very large timeslices, so xmms's scheduling latency | >| becomes large. The interactivity bonuses don't help, either. | > | >Clearly the "some is good, more is better" approach doesn't provide | >stable balance between sound and cpu hogs. It isn't a question of "how | >much" cpu, just "when"which works or not. | > | >This is sort of like the deadline scheduler in that it trades of | >throughput for avoiding jackpot cases. I think that's desired behaviour | >in a CPU schedular too, at least if used by humans. | > | | I'm not sure what you mean. There is nothing good to say about Ingo's | nice mechanism though (sorry Ingo, its otherwise a very nice | scheduler!).
Oh, I think the test5-mm4 behaviour is far better than yours in terms of throughput. I would expect that it could have several percent less system time, leaving it for cpu-bound user processes. However, on my little test machine (PII-350 w/ 96MB) running patch to get a kernel source tree ready makes the system damn near unusable. With your v15 patch neither patch nor a kernel build is a real problem (I don't use -j, there's only one processor and it doesn't help). I can happily read mail, run windows to remote machines to do admin, check web based monitors, and generally use the system. It's not a ball of fire, but it's old and slow moving, and I can identify with that ;-)
| In my scheduler, nice -20 processes get small timeslices so scheduling | latency stays low or even gets lower, while nice +19 ones get large | timeslices for lower context switches and better cache efficiency. As | you would like.
Clearly your timeslices don't get so large the system suffers. And I can run setiathome with a little nice, like -5, and it will get some time without slowing the important stuff on the system. Even at -19 it does keep going. On a small memory machine I hate to give pages to a process without giving it the CPU to justify the memory.
I'm going to try test5-n15 against test5-mm4 and test6-std with a server load, but for now I run your patch on machines I use as personal workstations. I haven't tried it SMP, that day will come. -- bill davidsen <davidsen@tmr.com> CTO, TMR Associates, Inc Doing interesting things with little computers since 1979. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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