On Wed, 17 Sep 2008, Mike Galbraith wrote: > On Wed, 2008-09-17 at 16:36 +0300, Ilpo Järvinen wrote: > > On Wed, 17 Sep 2008, Mike Galbraith wrote: > > > > > On Wed, 2008-09-17 at 14:49 +0200, Ingo Molnar wrote: > > > > > > > git log --pretty=format:"%h: %s" 2069f45..847106f | grep -viE \ > > > > 'block|alsa|pcmcia|sound|Merge|iosched|blk|DAC960|scsi|s390|paride|pktcdvd|filter|cdrom|drm' > > > > > > > > gives us: > > > > > > > > 7daf705: Start using the new '%pS' infrastructure to print symbols > > > > 6f0f0fd: security: remove register_security hook > > > > 93cbace: security: remove dummy module fix > > > > 5915eb5: security: remove dummy module > > > > b478a9f: security: remove unused sb_get_mnt_opts hook > > > > 32502b8: splice: fix generic_file_splice_read() race with page invalidation > > > > 8b3d356: ramfs: enable splice write > > > > a144ff0: xen: Avoid allocations causing swap activity on the resume path > > > > > > > > which really only leaves that security commit your bisection fingered. > > > > Which _slightly_ raises its likelyhood of being implicated. Structure > > > > size changes can move two formerly far-apart netperf-relevant symbols on > > > > the same cacheline, which can start cache ping-pong-ing badly. > > > > > > I sure hope it's something like ping-pong, it's driving me NUTS. > > > > How about dividing the problem to smaller blocks then by restoring > > parts of the change... > > Well, what I've done is check out the "bad" tree, reverted every darn > commit between there and the "good" tree, and then reverted the reverts > so I have a nice merge-free line and don't have to remember to think > backward. (probably sounds silly to git-foo masters) I'll try > bisecting that in the a.m. and see what happens. This was my initial idea (which was mainly an error from my part as I misread some shaids and midunderstood that the first regressing would be the merge instead of the actual change), but in here I meant taking parts of the 6f0f0fd on top of 6f0f0fd^. The most easiest way to do that actually might be to do in fact the opposite, ie., but some of the datastructure/layout changes back on top of 6f0f0fd and see if the performance get restored (besides testing the Eric's patch). -- i.
