Vivek Goyal wrote: > On Tue, Apr 21, 2009 at 09:57:23AM -0400, Mike Snitzer wrote: >> On Tue, Apr 21 2009 at 8:10am -0400, >> Ryo Tsuruta <ryov@xxxxxxxxxxxxx> wrote: >> >>> Hi Nauman, >>> >>>>> The real question is, once you create a version of dm-ioband that >>>>> co-operates with CFQ scheduler, how that solution would compare with >>>>> the patch set Vivek has posted? In my opinion, we need to converge to >>>>> one solution as soon as possible, so that we can work on it together >>>>> to refine and test it. >>>> I think I can do some help for your work. but I want to continue the >>>> development of dm-ioband, because dm-ioband actually works well and >>>> I think it has some advantages against other IO controllers. >>>> - It can use without cgroup. >>>> - It can control bandwidth on a per partition basis. >>>> - The driver module can be replaced without stopping the system. >>> In addition, dm-ioband can run on the RHEL5. >> RHEL5 compatibility does not matter relative to merging an I/O bandwidth >> controller upstream. So both the "can [be] use without cgroup" and "can >> run on RHEL5" features do not help your cause of getting dm-ioband >> merged upstream. In fact these features serve as distractions. > > Exactly. I don't think that "it can be used without cgroup" is a feature > or advantage. To me it is a disadvantage and should be fixed. cgroup is > standard mechanism to group tasks arbitrarily and we should use that to make > things working instead of coming up with own ways of grouping things and > terming it as advantage. > I agree. And for the case of cpu scheduler, there are user group scheduler and cgroup group scheduler, but Peter said he would like to see user group scheduler to be removed. > What do you mean by "The driver module can be replaced without stopping > the system"? I guess you mean that one does not have to reboot the system > to remove ioband device? So if one decides to not use the cgroup, then > one shall have to remove the ioband devices, remount the filesystems and > restart the application? > > With cgroup approach, if one does not want things to be classified, a user > can simply move all the tasks to root group and things will be fine. No > remounting, no application stopping etc. So this also does not look like > an advantage instead sounds like an disadvantage. > > Thanks > Vivek -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
