Hi, some news: I have applied patches succefully on top of 3.18-rc1 kernel. But don't seem to help is my case. (I think that blk-mq is working because I don't see any io schedulers on rbd devices, as blk-mq don't support them actually). My main problem is that I can't reach more than around 50000iops on 1 machine, and the problem seem to be the kworker process stuck at 100% of 1core. I had tried multiple fio process, on differents rbd devices at the same time, and I'm always limited à 50000iops. I'm sure that the ceph cluster is not the bottleneck, because if I launch another fio on another node at the same time, I can reach 50000iops on each node, and both are limited by the kworker process. That's why I thinked that blk-mq could help, but it don't seem to be the case. Is this kworker cpu limitation a known bug ? Regards, Alexandre ----- Mail original ----- De: "Alexandre DERUMIER" <aderumier@xxxxxxxxx> À: "Christoph Hellwig" <hch@xxxxxxxxxxxxx> Cc: "Ceph Devel" <ceph-devel@xxxxxxxxxxxxxxx> Envoyé: Vendredi 24 Octobre 2014 14:27:47 Objet: Re: krbd blk-mq support ? >>If you're willing to experiment give the patches below a try, not that >>I don't have a ceph test cluster available, so the conversion is >>untestested. Ok, Thanks ! I'll try them and see If I can improve qemu performance on a single drive with multiqueues. ----- Mail original ----- De: "Christoph Hellwig" <hch@xxxxxxxxxxxxx> À: "Alexandre DERUMIER" <aderumier@xxxxxxxxx> Cc: "Ceph Devel" <ceph-devel@xxxxxxxxxxxxxxx> Envoyé: Vendredi 24 Octobre 2014 12:55:01 Objet: Re: krbd blk-mq support ? If you're willing to experiment give the patches below a try, not that I don't have a ceph test cluster available, so the conversion is untestested. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
