On Wed, Jul 15, 2015 at 12:04:25PM -0400, Tejun Heo wrote: > Hello, Vivek. > > On Tue, Jul 14, 2015 at 12:09:08PM -0400, Vivek Goyal wrote: > > So now blkio.io_serviced will switch to accounting number of bios > > instead of number of requests? I feel given other stats, things > > are still confusing as other stats will similar name give stats > > about requests and not bios. > > > > IMHO, for a policy, either all the stats should be in bio or in terms > > of requests. Having a mix of these is even more confusing. > > Well, the actual problem is that we have so many stats which are > hardly useful except for debugging blkcg itself. Most of these stats > aren't meaningful to userland. > > > For example, IIUC, now blkio.io_serviced will keep count in terms of > > bios while blkio.io_queued will keep count in terms of number of > > requests. > > Why does that matter tho? io_queued tracks the number of requests > currently queued. It's not an accumulative stat. It isn't possible > to meaningfully correlate that stat with anything else there. > > > If we are keeping common stats at block layer (instead of per policy), > > I am wondering if it will make sense to reflect that in new cgroup > > files which are common to all policies in that cgroup, instead of being per > > policy. And deperecate respective per policy stat files over a period of > > time. > > So, that's the plan for unified hierarchy and this is the groundwork > for that. There's no point in disturbing interface for the > traditional hierarchies at this point. We can simply add the new > stats and use the new ones only on the unified hierarchy but frankly > how many identical stats should we keep? What we're doing is already > pretty silly and I don't really want to add more on top.
Hi Tejun, Ok. I am personally little apprehensive of changing the meaning of current stat, but I can live with it. Can you please also update the blkio-controller.txt to reflect these changes. I think following sections would require updation. blkio.throttle.io_serviced blkio.throttle.io_service_bytes And we could mention in blkio.io_serviced that accounting is terms of numeber of bios. Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
