we are using kernel client. in the condition 1), read rate can reach 110MB/s,that indicate we have added the readhead into the kernel client code. the problem is: in the conditon 2) the kernel client's read rate also declined 10~20MB/s, that confused us very much, any opinions? thanks 2011/10/11 Sage Weil <sage@xxxxxxxxxxxx>: > On Tue, 11 Oct 2011, huang jun wrote: >> hi,all >> Recently, we test the samba read performance,and find something strange. >> there are two groups to test: >> the cluster include 1 MON and 1 MDS,and >> 1) 2 OSDs on the same machine >> 2) 2 OSDs on the different machine >> when we use samba to test read, >> in the first condition it is about 110MB/s, but in the second >> condition it is only 60MB/s. >> >> we anlysed it from the debug log /var/log/ceph/osd.*.log, >> in the condition 1), the OSD spends about 7~8ms (from sending >> osd_op_reply to getting the next client read request) >> but in 2) we spends about 12~14ms. > > The osd_op_reply message shows up in the osd log when the message is > queued. Since these are reads, the messages are large (they carry the > data payload), and will take more time to send over the wire when passing > over the network. > > It sounds like the problem is that only a single read is being issued at a > time (i.e. readahead isn't working). Are you using the kernel client or > libceph/cfuse? Readahead was only recently fixed in the kernel client. > The patches are in the master branch of ceph-client.git, but are not yet > upstream; they should be merged in 3.2-rc1 in the upcoming merge window. > > sage > -- 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
