Re: dm-ioband + bio-cgroup benchmarks

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Sep 24, 2008 at 07:34:14PM +0900, Hirokazu Takahashi wrote:
> Hi,
> 
> > > It's possible the algorithm of dm-ioband can be placed in the block layer
> > > if it is really a big problem.
> > > But I doubt it can control every control block I/O as we wish since
> > > the interface the cgroup supports is quite poor.
> > 
> > Had a question regarding cgroup interface. I am assuming that in a system,
> > one will be using other controllers as well apart from IO-controller.
> > Other controllers will be using cgroup as a grouping mechanism.
> > Now coming up with additional grouping mechanism for only io-controller seems
> > little odd to me. It will make the job of higher level management software
> > harder.
> > 
> > Looking at the dm-ioband grouping examples given in patches, I think cases
> > of grouping based  in pid, pgrp, uid and kvm can be handled by creating right
> > cgroup and making sure applications are launched/moved into right cgroup by
> > user space tools. 
> 
> Grouping in pid, pgrp and uid is not the point, which I've been thinking
> can be replaced with cgroup once the implementation of bio-cgroup is done.
> 
> I think problems of cgroup are that they can't support lots of storages
> and hotplug devices, it just handle them as if they were just one resource.
> I don't insist the interface of dm-ioband is the best. I just hope the
> cgroup infrastructure support this kind of resources.
> 

Sorry, I did not understand fully. Can you please explain in detail what
kind of situation will not be covered by cgroup interface.

Thanks
Vivek