Messages in this thread |  | | | Date | Thu, 5 Aug 2004 10:25:31 -0700 | | From | William Lee Irwin III <> | | Subject | Re: Severe I/O performance regression 2.6.6 to 2.6.7 or 2.6.8-rc3 |
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On Thu, Aug 05, 2004 at 12:02:09PM -0500, Mr. Berkley Shands wrote: > Two severe disk read bugs: > In a nutshell (see attached for gory details). Moving from 2.6.6 to > 2.6.7 dropped multi-threaded RAID0 > read performance from 429MB/Sec to 81MB/Sec. Single threaded reads > improved 368MB/Sec to 418MB/Sec. > The code in drivers/md has no effect on this problem. Clearly this is a > thread access issue. Redhat ES3.0 > on x86_64 or i686. The underlying hardware is capable of 955MB/Sec disk > reads off 28 drives, > 541MB/Sec off 14 drives. Tuning I/O block size (11KB to 239KB) and > BLKRASET size (448 to 1024 or more) > helps a little. System idle goes from 0% to 50% (2.6.6 to 2.6.8-rc3).
By any chance could you do binary search on the bk snapshots between 2.6.6 and 2.6.7?
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