>>At high queue-depths and high IOPS, I would suspect that the bottleneck is the single, coarse-grained mutex protecting the cache data structures. It's been a back burner item to refactor the current cache mutex into finer->>grained locks. >> >>Jason Thanks for the explain Jason. Anyway, inside qemu, I'm around 35-40k with or without rbd_cache, so it's make not too much difference currently. (maybe some other qemu bottleneck). ----- Mail original ----- De: "Jason Dillaman" <dillaman@xxxxxxxxxx> À: "Mark Nelson" <mnelson@xxxxxxxxxx> Cc: "aderumier" <aderumier@xxxxxxxxx>, "pushpesh sharma" <pushpesh.eck@xxxxxxxxx>, "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx> Envoyé: Mardi 9 Juin 2015 15:39:50 Objet: Re: [ceph-users] rbd_cache, limiting read on high iops around 40k > In the past we've hit some performance issues with RBD cache that we've > fixed, but we've never really tried pushing a single VM beyond 40+K read > IOPS in testing (or at least I never have). I suspect there's a couple > of possibilities as to why it might be slower, but perhaps joshd can > chime in as he's more familiar with what that code looks like. > At high queue-depths and high IOPS, I would suspect that the bottleneck is the single, coarse-grained mutex protecting the cache data structures. It's been a back burner item to refactor the current cache mutex into finer-grained locks. Jason -- 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
