I/O Scheduling

I/O Scheduling

[Libin Varghese]

Hi all,
        Is there any work done on new I/O scheduling techniques (other
than as, cfq, noop, deadline)?

Regards,
Libin Varghese

Re: I/O Scheduling

[Florian Schmidt]

On Sat, 28 Jan 2006 15:28:54 +0530
Libin Varghese <libinv@gmail.com> wrote:

> Hi all,
>         Is there any work done on new I/O scheduling techniques (other
> than as, cfq, noop, deadline)?

Hi,

i'm also interested in these. Especially I/O priorities per process/task
similar to scheduling priorities. It would be just awesome to be able to
give i.e. a hd recording program (or any other data aquisition or
playback program) a high I/O priority.

Image no buffer overruns ever in a hd recorder. Or no more video
dropouts when watching a movie and at the same time copying a file from
the same partition you play the video from.

Is there any work done in this area. I faintly remember to have read
about something like this over a year ago, but have forgotten all the
specifics.

Thanks for all infos and regards,
Florian Schmidt

-- 
Palimm Palimm!
http://tapas.affenbande.org

Re: I/O Scheduling

[Lee Revell]

On Sat, 2006-01-28 at 18:54 +0100, Florian Schmidt wrote:
> 
> i'm also interested in these. Especially I/O priorities per
> process/task similar to scheduling priorities. It would be just
> awesome to be able to give i.e. a hd recording program (or any other
> data aquisition or playback program) a high I/O priority.
> 

I believe it's already implemented for the CFQ scheduler only, but the
patch does not seem to be in mainline.

Jens, what's the status of this?

Lee

Re: I/O Scheduling

[Jens Axboe]

On Sat, Jan 28 2006, Lee Revell wrote:
> On Sat, 2006-01-28 at 18:54 +0100, Florian Schmidt wrote:
> > 
> > i'm also interested in these. Especially I/O priorities per
> > process/task similar to scheduling priorities. It would be just
> > awesome to be able to give i.e. a hd recording program (or any other
> > data aquisition or playback program) a high I/O priority.
> > 
> 
> I believe it's already implemented for the CFQ scheduler only, but the
> patch does not seem to be in mainline.
> 
> Jens, what's the status of this?

It's merged, since 2.6.13.

-- 
Jens Axboe

Re: I/O Scheduling

[Lee Revell]

On Sat, 2006-01-28 at 20:18 +0100, Jens Axboe wrote:
> On Sat, Jan 28 2006, Lee Revell wrote:
> > On Sat, 2006-01-28 at 18:54 +0100, Florian Schmidt wrote:
> > > 
> > > i'm also interested in these. Especially I/O priorities per
> > > process/task similar to scheduling priorities. It would be just
> > > awesome to be able to give i.e. a hd recording program (or any other
> > > data aquisition or playback program) a high I/O priority.
> > > 
> > 
> > I believe it's already implemented for the CFQ scheduler only, but the
> > patch does not seem to be in mainline.
> > 
> > Jens, what's the status of this?
> 
> It's merged, since 2.6.13.
> 

OK, I was looking at an old patch, the API must have changed.  Can it be
controlled per thread, independently of the nice value/RT priority?

Lee

Re: I/O Scheduling

[Jens Axboe]

On Sat, Jan 28 2006, Lee Revell wrote:
> On Sat, 2006-01-28 at 20:18 +0100, Jens Axboe wrote:
> > On Sat, Jan 28 2006, Lee Revell wrote:
> > > On Sat, 2006-01-28 at 18:54 +0100, Florian Schmidt wrote:
> > > > 
> > > > i'm also interested in these. Especially I/O priorities per
> > > > process/task similar to scheduling priorities. It would be just
> > > > awesome to be able to give i.e. a hd recording program (or any other
> > > > data aquisition or playback program) a high I/O priority.
> > > > 
> > > 
> > > I believe it's already implemented for the CFQ scheduler only, but the
> > > patch does not seem to be in mainline.
> > > 
> > > Jens, what's the status of this?
> > 
> > It's merged, since 2.6.13.
> > 
> 
> OK, I was looking at an old patch, the API must have changed.  Can it be
> controlled per thread, independently of the nice value/RT priority?

Yes it can, get a recent util-linux and look at ionice (there's a man
page, too).

-- 
Jens Axboe