>>Thinking about this again, I doubt >>that lengthening the duration with a hardcoded value benifits everyone; and >>before Alexandre's reply on old server/slow disks
With 1ms sleep, I can reproduce the hang 100% with a fast cpu (xeon e5 v3 3,1ghz) and source raw file on nfs. ----- Mail original ----- De: "Fam Zheng" <f...@redhat.com> À: "Stefan Hajnoczi" <stefa...@gmail.com> Cc: "Kevin Wolf" <kw...@redhat.com>, "qemu-devel" <qemu-de...@nongnu.org>, qemu-block@nongnu.org Envoyé: Vendredi 10 Juillet 2015 08:43:50 Objet: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan On Thu, 07/09 14:02, Stefan Hajnoczi wrote: > This patch only converts the mirror block job to use the new relax > function. The other block jobs (stream, backup, commit) are still using > a 0 ns delay and are therefore broken. They should probably be > converted in the same series. That's because they all can be perfectly mitigated by setting a reasonable "speed" that matchs the host horsepower. Thinking about this again, I doubt that lengthening the duration with a hardcoded value benifits everyone; and before Alexandre's reply on old server/slow disks, I don't recall any report, because the coroutines would already yield often enough, when waiting for IO to complete. So I am not sure whether they're broken in practice. Fam
