On Fri, Mar 28, 2014 at 11:09 AM, Jorgen Lundman <[email protected]>wrote:
> > Hello masters! > > So we appear to have reached minimum stability to start looking at > performance, over at the OS X camp. > > And initial checks would indicate that there is possibly something wrong. > Most information I have gathered, which is not much, is available here; > > https://openzfsonosx.org/wiki/Development#iozone > > Which includes some quick iozone tests. For example; > > HFS read: > https://openzfsonosx.org/w/images/9/9c/Hfs2_read.png > > ZFS read: > https://openzfsonosx.org/w/images/1/11/Zfs2_read.png I don't know enough about these tests to make any real definitive statements, but the results show HFS peaking around 2GB/sec, and ZFS peaking around 6GB/s. Sounds good to me, though it's perplexing that throughput goes down as file size goes up. --matt > > > > Which would suggest that we come along at about a third of the speed. > > Now at the bottom of the whole ZFS layout, we end up in vdev_disk.c, and > issue the next bit of IO using buf*() calls. Ie; > > > https://github.com/openzfsonosx/zfs/blob/vnode_threadX/module/zfs/vdev_disk.c#L341 > > And when IO is done, we immediately call zio_interrupt(). > > I would like to believe that there is not so many ways I can get that > wrong, so it should be something in the area "above". > > Possibly the ZIO pipeline which issue the requests in the first place. Lock > contention elsewhere maybe? Most of the internals of ZFS is as close to ZOL > as I could manage. > > Alas, my knowledge lies in the edges of ZFS. Ie, where ZFS interfaces with > the kernel, so I am not so sure where I should poke next. > > I am hoping for pointers as to where others would look. Can I confirm that > ZIO is lining up multiple requests in a row (that is what it does right?) > > A flamegraph of bonnie running its "creating files" phase looks like; > > https://openzfsonosx.org/w/images/a/a2/VX_create.svg > > > Sincerely, > > Lund > > -- > Jorgen Lundman | <[email protected]> > Unix Administrator | +81 (0)3 -5456-2687 ext 1017 (work) > Shibuya-ku, Tokyo | +81 (0)90-5578-8500 (cell) > Japan | +81 (0)3 -3375-1767 (home) > _______________________________________________ > developer mailing list > [email protected] > http://lists.open-zfs.org/mailman/listinfo/developer >
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