On Tue, Sep 13, 2011 at 11:09:46AM +0800, Zhi Yong Wu wrote: > On Fri, Sep 9, 2011 at 10:44 PM, Marcelo Tosatti <mtosa...@redhat.com> wrote: > > On Thu, Sep 08, 2011 at 06:11:07PM +0800, Zhi Yong Wu wrote: > >> Note: > >> 1.) When bps/iops limits are specified to a small value such as 511 > >> bytes/s, this VM will hang up. We are considering how to handle this > >> senario. > > > > You can increase the length of the slice, if the request is larger than > > slice_time * bps_limit. > Yeah, but it is a challenge for how to increase it. Do you have some nice > idea?
If the queue is empty, and the request being processed does not fit the queue, increase the slice so that the request fits. That is, make BLOCK_IO_SLICE_TIME dynamic and adjust it as described above (if the bps or io limits change, reset it to the default BLOCK_IO_SLICE_TIME). > >> 2.) When "dd" command is issued in guest, if its option bs is set to > >> a large value such as "bs=1024K", the result speed will slightly bigger > >> than the limits. > > > > Why? > This issue has not existed. I will remove it. > When drive bps=1000000, i did some testings on guest VM. > 1.) bs=1024K > 18+0 records in > 18+0 records out > 18874368 bytes (19 MB) copied, 26.6268 s, 709 kB/s > 2.) bs=2048K > 18+0 records in > 18+0 records out > 37748736 bytes (38 MB) copied, 46.5336 s, 811 kB/s > > > > > There is lots of debugging leftovers in the patch. > sorry, i forgot to remove them. > > > >
