On Sun, Mar 11, 2018 at 02:02:03PM +0100, Zdenek Kabelac wrote: > Hi > > I've noticed quite some drop of performance (around 15% in some cases) where > execution of lvm2 tests took longer time - and while tests itself should not > really load CPU system - the overall running time just got bigger. > > Running bisect game pointed clearly to this commit: > > --- > > commit 44c02a2c3dc55835e9f0d8ef73966406cd805001 > Author: Al Viro <v...@zeniv.linux.org.uk> > Date: Thu Oct 5 12:59:44 2017 -0400 > > dev_ioctl(): move copyin/copyout to callers > > > --- > > clear revert of this commit on top of 3266b5bd97eaa72793df0b6e5a106c69ccc166c4 > (recent ~4.16-rc4) restored timing of tests back. > > > I'm not sure why - so at this moment this is just a patch causing 15% longer > running times on lvm2 test suite.
I find it very hard to believe, TBH. It doesn't go anywhere near drivers/md; could you profile the damn thing and see where does it spend that extra time? It really doesn't touch anything on non-sockets...
