Hello Roman, I consider *the difference* between BlueStore and MemStore in ceph-osd as rough boundary on how much is achievable for this single component. It's rather unlikely that SeaStore can be beat MemStore. ;-) Still, it's very, very rough due to the dependencies between components. For example, it's not impossible that a syscall in messenger potentially decreases IPC also in ObjectStore. So, please take it with a grain of salt. Regards, Radek On Wed, Jan 15, 2020 at 12:05 PM Roman Penyaev <rpenyaev@xxxxxxx> wrote: > > On 2020-01-14 23:07, Mark Nelson wrote: > > On 1/14/20 2:05 PM, Radoslaw Zarzynski wrote: > >> On Tue, Jan 14, 2020 at 12:13 PM Roman Penyaev <rpenyaev@xxxxxxx> > >> wrote: > >>> Am I right that you are talking about several connections between > >>> a primary osd and a single client instance? At least I'm picturing > >>> that each connection represents a software cpu (or how this thread, > >>> which does scheduling, is called?) on osd side. Then I can imagine > >>> that a request to a PG goes to one of the connections by simple > >>> modulo operation (something like PG_id % Number_of_conns). So all > >>> requests to a PG from all clients will be eventually handled by one > >>> of the cpu threads. Something like that? > >> Yup, basically a set of PGs would get its own crimson-msgr instance > >> to let clients to talk directly with the proper CPU core – without > >> crossbar or, in general, any data / message passing between CPU cores > >> on hot paths. > >> > >>> May I take a look on the link with numbers and what exactly > >>> persistent > >>> object store you've mentioning? > >> +Mark. > >> This was the testing Mark has initially mentioned. ceph-osd + > >> BlueStore > >> has been compared with ceph-osd + MemStore during random reads. > >> I can't find the spreadsheet but I asked Mark today. > >> > > > > Found it: > > > > > > https://docs.google.com/spreadsheets/d/1kfzbvtdhUvrzjn9eW0r6Fqrm8gE6X0bmZnECfrLSt8g/edit?usp=sharing > > > > Thanks for sharing. Do I understand correctly that this ~270k cycles/io > for writes can be treated as a best estimation for objectstore? > Kind of ideal boundary to which we should strive for? (doing comparison > on the same hardware, of course). Since memstore is log-less, this > estimation, of course, is hardly reachable, but can be treated as > a perfect unattainable reference. > > -- > Roman > _______________________________________________ Dev mailing list -- dev@xxxxxxx To unsubscribe send an email to dev-leave@xxxxxxx
