Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [PATCH][CFT] new IO scheduler for 2.4.20 | Date | Sat, 31 May 2003 09:40:41 +1000 |
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On Sat, 31 May 2003 08:09, Neil Schemenauer wrote: > The major benefit of this patch is that read latency is much lower while > lots of writes are occuring. On my machine, running: > > while :; do dd if=/dev/zero of=foo bs=1M count=1000 conv=notrunc; done > > makes 2.4.20 unusable. With this patch the "write bomb" causes no > particular problems. > > With this version of the patch I've improved the bulk read performance > of the elevator. The bonnie++ results are now: > > -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- > Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP > 2.4.20 1G 13001 97 34939 18 13034 7 12175 92 34112 14 > 2.4.20-nas 1G 12923 98 36471 17 13340 8 10809 83 35569 13 > > Note that the "rewrite" and "per-char read" stats are slightly bogus for > 2.4.20-nas. Reads get a boost in priority over writes. When the > "per-char read" test has started there is still some writing happening > from the rewrite test. I think the net effect is that the "rewrite" > number is too high and the "per-char read" number is too low. > > I would be very pleased if someone could run some tests on using bonnie, > contest, or their other favorite benchmarks and post the results.
Nice to see 2.4 getting some attention. I'll try and get around to contesting it.
How does this compare to akpm's read-latency2 patch that he posed some time ago? That seems to make a massive difference but was knocked back for style or approach.
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