>>Oh, that's without the blk-mq patch? Yes, sorry, I don't how to use perf with a custom compiled kernel. (Usualy I'm using perf from debian, with linux-tools package provided with the debian kernel package)
>>Either way the profile doesn't really sum up to a fully used up cpu. But I see mostly same behaviour with or without blk-mq patch, I have always 1 kworker at around 97-100%cpu (1core) for 50000iops. I had also tried to map the rbd volume with nocrc, it's going to 60000iops with same kworker at around 97-100%cpu ----- Mail original ----- De: "Christoph Hellwig" <[email protected]> À: "Alexandre DERUMIER" <[email protected]> Cc: "Ceph Devel" <[email protected]> Envoyé: Mardi 28 Octobre 2014 19:07:25 Objet: Re: krbd blk-mq support ? On Mon, Oct 27, 2014 at 11:00:46AM +0100, Alexandre DERUMIER wrote: > >>Can you do a perf report -ag and then a perf report to see where these > >>cycles are spent? > > Yes, sure. > > I have attached the perf report to this mail. > (This is with kernel 3.14, don't have access to my 3.18 host for now) Oh, that's without the blk-mq patch? Either way the profile doesn't really sum up to a fully used up cpu. Sage, Alex - are there any ordring constraints in the rbd client? If not we could probably aim for per-cpu queues using blk-mq and a socket per cpu or similar. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
