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(Andrea, the previous version of this mail wasn't supposed to go out yet. I fat-fingered and sent it before I was done. This is the full version.) Andrea Arcangeli: > On Sat, Jan 19, 2002 at 01:39:22PM -0500, Adam Kropelin wrote: > > Andrea Arcangeli: > > > With -aa something sane along the above lines is: > > > > > > /bin/echo "10 2000 0 0 500 3000 30 5 0" > /proc/sys/vm/bdflush > > > > Unfortunately, those adjustments on top of 2.4.18-pre2aa2 set a new record for > > worst performance: 7:19. > > then please try to decrease the nfract variable again, the above set it > to 2000, if you've a slow harddisk maybe that's too much, so you can try > to set it to 500 again. Yes, the harddisk is definitely slow: it's a hw RAID5 partition with older drives, so writes are pretty slow. I tried various nfract settings: /bin/echo "10 300 0 0 500 3000 30 5 0" > /proc/sys/vm/bdflush 7:33 /bin/echo "10 500 0 0 500 3000 30 5 0" > /proc/sys/vm/bdflush 6:00 /bin/echo "10 800 0 0 500 3000 30 5 0" > /proc/sys/vm/bdflush 7:17 nfract=500 seems to be the best and gets much closer to the performance of rmap and -ac. Writeout is still very bursty compared to the other kernels, but that may not really matter, I don't know. > I'd also give a try with the below settings: > > /bin/echo "10 500 0 0 500 3000 80 8 0" > /proc/sys/vm/bdflush 7:08 <snip> > Also just in case, I'd suggest to try to repeat each benchmark three > times, so we know we are not bitten by random variations in the numbers. I've been doing a variation on that theme already. The numbers I've been reporting are best of 2 runs. I have never seen the 2 runs differ by more than +/- 10 seconds. --Adam - 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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