On Tue, Nov 22, 2016 at 04:27:15PM -0500, Tejun Heo wrote: > Hello, > > On Mon, Nov 14, 2016 at 02:22:14PM -0800, Shaohua Li wrote: > > throtl_slice is important for blk-throttling. A lot of stuffes depend on > > it, for example, throughput measurement. It has 100ms default value, > > which is not appropriate for all disks. For example, for SSD we might > > use a smaller value to make the throughput smoother. This patch makes it > > tunable. > > It bothers me a bit because time slice doesn't mean anything inherent > to throttling. It really is an implementation detail - throttling can > be implemented at per-operation level without time slice involved at > all. It's okay to expose the knob if necessary but the meaning of the > knob is almost completely arbitrary to users (as it has no inherent > meaning).
Hmm, it's not a real 'time slice'. The name is a bit confusion. Maybe rename it to 'throtl_interval' or 'throtl_sampling_time'? not sure. bandwidth and iops are always in terms of a time interval we measure them. We can't say the iops/bw for a single io. So this is really a tuable knob. Thanks, Shaohua
