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Ken Brownfield: > Do you get more even throughput with this: > > /bin/echo "10 0 0 0 500 3000 10 0 0" > /proc/sys/vm/bdflush > > It seems to help significantly for me under heavy sustained I/O load. With a little modification, Ken's suggestion makes -rmap11c a winner on my test case. /bin/echo "10 0 0 0 500 3000 30 0 0" > /proc/sys/vm/bdflush Switching to synchronous bdflush a little later than Ken did brings performance up to ~2000 blocks/sec, which is similar to older -ac kernels. This writeout rate is very consistent (even more so than -ac) and seems to be the top end in all large writes to the RAID (tried FTP, samba, and local balls-to-the-wall "cat /dev/zero >..."), which helps show that this is not a network driver or protocol interaction. The same bdflush tuning (leaving aa's additional parameters at their defaults) on 2.4.18pre2aa2 yields some improvement, but rmap is consistently faster by a good margin. 2.4.17 performs worse with this tuning and is pretty much eating dust at this point. Latest Results: 2.4.17-rmap11c: 5:41 (down from 6:58) 2.4.18-pre2aa2: 6:31 (down from 7:10) 2.4.17: 7:06 (up from 6:57) Congrats, Rik and thanks, Ken! --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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