Messages in this thread |  | | Date | Tue, 21 Nov 2000 12:36:08 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH] livelock in elevator scheduling |
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On Tue, Nov 21 2000, kumon@flab.fujitsu.co.jp wrote: > > Believe it or not, but this is intentional. In that regard, the > > function name is a misnomer -- call it i/o scheduler instead :-) > > I never believe it intentional. If it is true, the current kernel > will be suffered from a kind of DOS attack. Yes, actually I'm a > victim of it.
The problem is caused by the too high sequence numbers in stock kernel, as I said. Plus, the sequence decrementing doesn't take request/buffer size into account. So the starvation _is_ limited, the limit is just too high.
> By Running ZD's ServerBench, not only the performance down, but my > machine blocks all commands execution including /bin/ps, /bin/ls... , > and those are not ^C able unless the benchmark is stopped. Those > commands are read from disks but the requests are wating at the end of > I/O queue, those won't be executed.
If performance is down, then that problem is most likely elsewhere. I/O limited benchmarking typically thrives on lots of request latency -- with that comes better throughput for individual threads.
> Anyway, I'll try your patch.
Thanks
-- * Jens Axboe <axboe@suse.de> * SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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