On Mon, Sep 4, 2017 at 6:55 PM, Darrick J. Wong <darrick.wong@xxxxxxxxxx> wrote: > On Mon, Sep 04, 2017 at 03:15:28PM +0300, Amir Goldstein wrote: >> Lost IOs have been observed with the default aio=threads with >> QEMU 2.5.0 when running crash consistency tests. >> The issue has not been observed with QEMU 2.9.0. >> Native AIO is probably better for our goal which is test proofing >> production systems. >> >> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> >> --- >> >> Ted, >> >> Not sure you have been following the crash consistency tests threads. >> >> Anyway, I ran into an issue of sucessfuly completed bio's that >> did not make it to storage device when running in kvm-xfstests. >> >> Josef reported that he did not observe the issue with newer QEMU >> and the issue is gone with aio=native on my version of QEMU. >> >> Crash consistency tests still can't run properly on kvm-xfstests >> without this fix to kernel: >> https://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git/commit/?h=dm-log-writes-fixes&id=08c7d64773091c7d2e0147da7064aa4dc297629d >> After the fix is merged I will post a patch to enable running >> dm-log-write tests in kvm-xfstest. >> >> Mean while, the change to aio=native seems like a good move >> anyway and if I observed a bio black hole in one test, who's to say >> they don't exist for other tests as well. >> >> Amir. >> >> >> kvm-xfstests/kvm-xfstests | 19 +++++++++++++------ >> 1 file changed, 13 insertions(+), 6 deletions(-) >> >> diff --git a/kvm-xfstests/kvm-xfstests b/kvm-xfstests/kvm-xfstests >> index 305e2f5..98bd76a 100755 >> --- a/kvm-xfstests/kvm-xfstests >> +++ b/kvm-xfstests/kvm-xfstests >> @@ -101,15 +101,22 @@ chmod 400 "$VDH" >> >> mkdir -p /tmp/kvm-xfstests-$USER >> >> +# Lost IOs have been observed with the default aio=threads with >> +# QEMU 2.5.0 when running crash consistency tests. > > Note however that Ubuntu 16.04 LTS is still on qemu 2.5, so perhaps > it's worth the trouble to check the qemu version prior to enabling > native aio support? > hmm.. I am using Ubuntu 16.04/QEMU 2.5 that is why I am posting this patch The default aio=threads is allegedly buggy on QEMU 2.5 so I am proposing to always use aio=native, which is probably the right configuration for several other reasons Amir. -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
