On Wed, Apr 23, 2014 at 03:00:43PM -0400, Tejun Heo wrote: > Hello, > > On Wed, Apr 23, 2014 at 02:58:35PM -0400, Vivek Goyal wrote: > > Oh, sorry, I had misunderstood your question. > > > > - Number of IOs serviced will be different at throttling layer and > > CFQ layer as throttling accounts IO in terms of bios and CFQ > > accounts in terms of number of requests. > > But shouldn't it be possible to determine that from merged count? Or > we can just expose both bio and request counts at block core layer. > The point is that there's nothing controller specific about these > stats. In general this idea makes sense. Exporting both request and bio will solve the problem of io accounting. Also that should allow us to get rid of blkio.io_merged. What about sync/async differentiation? Throttling layer seems to flag a request sync only if bio->bi_rw flag has REQ_SYNC set. While CFQ seems to consider request sync if bio is either read or bio->bi_rw has REQ_SYNC flag set. So we need to make this definition uniform. Or I am wondering do we really need to export sync/async data. (Again put in by google folks). How useful this info really is. Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
