On Tue, November 3, 2009 9:06 pm, Christoph Hellwig wrote: > On Mon, Nov 02, 2009 at 01:55:54PM -0800, Andrew Morton wrote: >> On Tue, 13 Oct 2009 12:09:55 +0200 >> Laurent CORBES <laurent.corbes@xxxxxxxxxxxx> wrote: >> >> > Hi all, >> > >> > While benchmarking some systems I discover a big sequential read >> performance >> > drop using ext3 on ~ big files. The drop seems to be introduced in >> 2.6.30. I'm >> > testing with 2.6.28.6 -> 2.6.29.6 -> 2.6.30.4 -> 2.6.31.3. >> >> Seems that large performance regressions aren't of interest to this >> list :( > > No sure which list you mean, but dm-devel is for dm, not md. We're also > seeing similarly massive performance drops with md and ext3/xfs as > already reported on the list. Someone tracked it down to writeback > changes as usual, but there it got stuck. I'm still looking - running some basic tests on 4 filesystems over half a dozen recent kernels to see what has been happening. I have a suspicion that there a multiple problems. In particular, XFS has a strange degradation which was papered over by commit c8a4051c3731b. I'm beginning to wonder if it was caused by commit 17bc6c30cf6bf but I haven't actually tested that yet. NeilBrown -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
