Hi, Dhaval Giani <dhaval@xxxxxxxxxxxxxxxxxx> wrote: > > I know that cgroup is a very well defined functionality, that is why > > dm-ioband also supports throttling per cgroup. But how are we supposed > > to do throttling on the system which doesn't support cgroup? > > As I wrote in another mail to Vivek, I would like to make use of > > dm-ioband on RHEL 5.x. > > Hi Ryo, > > I am not sure that upstream should really be worrying about RHEL 5.x. > cgroups is a relatively mature solution and is available in most (if not > all) community distros today. We really should not be looking at another > grouping solution if the sole reason is that then dm-ioband can be used > on RHEL 5.x. The correct solution would be to maintain a separate patch > for RHEL 5.x then and not to burden the upstream kernel. RHEL 5.x is not the sole reason for that. > > And I don't think that the grouping methods are not complicated, just > > stack a new device on the existing device and assign bandwidth to it, > > that is the same method as other device-mapper targets, if you would > > like to assign bandwidth per thread, then register the thread's ID to > > the device and assign bandwidth to it as well. I don't think it makes > > users confused. > > > > > I would tend to agree with this. With other resource management > > > controllers using cgroups, having dm-ioband use something different will > > > require a different set of userspace tools/libraries to be used. > > > Something that will severly limit its usefulness froma programmer's > > > perspective. > > > > Once we create a dm-ioband device, the device can be configured > > through the cgroup interface. I think it will not severly limit its > > usefulness. > > > > My objection is slightly different. My objection is that there are too > many interfaces to do the same thing. Not too many, There are only two interfaces device-mapper and cgroup. > Which one of these is the recommended one? I think whichever users like, it's up to users. > WHich one is going to be supported? Both device-mapper and cgroup interfaces are supported continuously. > If we say that cgroups is not the preferred interface, do the > application developers need to use yet another library for io > control along with cpu/memory control? I don't think that cgroup is not the preferred interface, especially not if dm-ioband uses with cpu/memory controller together. Once a dm-ioband device is created, all configurations for the device can be done through the cgroup interface like other cgroup subsystems. It does not require a different set of userspace tools/libraries to be used. I think it is natural to make dm-ioband can be configured by device-mapper's interface since dm-ioband is a device-mapper driver, and it extends use case, rather it limits usefulness. Thanks, Ryo Tsuruta -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
