On 28.06.2016 17:28, Sascha Silbe wrote: > qemu-iotests #141 is relying on the test being able to operate on a > block job it just started before further progress is being made on > this block job. This fails regularly on some hosts because the time > slice is just 100ms and it often takes longer than that to start the > additional processes required to trigger the operation. It's > particularly easy to reproduce under 100% CPU load. > > I originally noticed and analysed this during 2.6 hard > freeze. Eventually the legacy rate limiting code currently used by the > block jobs will be replaced by the refactorings to use BlockBackends > which have their own rate limiting implementation. There was some hope > [1] this would land in 2.7, but since it's not in master yet (at least > as of commit a01aef5d) I prepared an alternative fix that can go into > 2.7. > > Sascha Silbe (1): > Improve block job rate limiting for small bandwidth values > > block/commit.c | 13 +++++-------- > block/mirror.c | 4 +++- > block/stream.c | 12 ++++-------- > include/qemu/ratelimit.h | 43 ++++++++++++++++++++++++++++++++++--------- > 4 files changed, 46 insertions(+), 26 deletions(-) > > [1] mid:20160408123115.gh4...@noname.redhat.com > "Re: [Qemu-devel] [Qemu-block] [PATCH 6/7] qemu-iotests: 141: > reduce likelihood of race condition on systems with fast IO" by > Kevin Wolf <kw...@redhat.com> on 2016-04-08.
Thanks Sascha, I've applied the patch to my block tree: https://github.com/XanClic/qemu/commits/block Max
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