Hi, Paolo,
Sorry, but I don't know what does bisect mean exactly. Could you please explain it? I feel it might be some kernel configuration items introduce this problem. I am also trying other kernel versions from 2.6.34 to 2.6.38 (2.6.33.3 has good performance like 2.6.32) and will show you the results. Thanks, Yi At 2015-06-24 20:20:02, "Paolo Bonzini" <pbonz...@redhat.com> wrote: > > >On 24/06/2015 14:14, cauchy-love wrote: >> I have updated the kernel of CentOS 6.5 from 2.6.32 to higher >> versions (2.6.39+) and found the disk IO write performance of my guest >> OS degraded significantly (around 1/10 of 2.6.32) while read performance >> was not influenced. That means everything is the same (i.e., hardware >> configurations, BIOS, filesystems (ext4)) except the kernel. I would be >> greatly apprieciated if you can provide some help about debugging this >> problem. I have tried to trace the qemu but didn't get any progress. > >Can you bisect it further between 2.6.32 and 2.6.39? > >Stefan, does it ring any bell? > >Paolo
