On Wed, 5 Nov 2014, jianpeng wrote: > Dong Yuan <yuandong <at> unitedstack.com> writes: > > > > > Hi Sage, > > > > I am now working with the BP osd: update Transaction encoding, but the > > Transaction::get_data_alignment make me confused. > > > > This method give the alignment which is used by FileJournal to do > > better buffer build. It calculate the alignment by largest_data_off > > and get_data_offset() while the first is an offset of some object and > > the second is an offset of the transaction encode result. I am not > > sure there is any reason to do calculation between them. > > > > The code works fine, probably because any result is fine for > > Transaction::get_data_alignment, while > > FileJournal::prepare_single_write can use any alignment value to build > > logical bufferlist. > > > > Can you give me some explanation? Thank you. > > > > Hi, i send a pull request to reduce the memcopy cause by unalignment. > https://github.com/ceph/ceph/pull/2803 > I think get_data_offset() should not care largest_data_off. I finally got to testing this and it looks good. Pulled the patches manually into master. Sorry it took so long! For the last two MOSDSubOp, I think those changes should be done as part of this ticket http://tracker.ceph.com/issues/9961 which will replace the common client replication op to use a fresh message type that is properly optimized. Jianpeng, is this something you might be interested in working on? We talked with Haomai about it during CDS but I think he and Yuan Dong will be occupied with the ObjectStore::Transaction encoding first, and I would really like to see this done in time for hammer (jan 1f freeze). Thanks! 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
