Re: IO stats in /proc/partitions

[Marcelo Tosatti]

On Sat, 4 May 2002 [e-mail] wrote:

> Earlier I noticed that RedHat did put some statistics in
> /proc/partitions. That was bad, but I assumed that it was
> their laziness, being too busy to do a proper job.
> 
> However, I see that these days the pollution of /proc/partitions
> is becoming official - it is part of patch-2.4.19-pre7.
> I strongly object, and hope it is not too late to revert this.
> 
> Things must do one thing, and one thing well.
> The task of /proc/partitions is to list which partitions the
> kernel knows about. When I implemented it I thought that adding
> the starting offset would be superfluous, but in fact I now realize
> that that is required for several applications.
> So, /proc/partitions must be updated sooner or later with an
> additional field "starting offset". Possibly more fields to
> enable identification. Sometimes it is really difficult to
> determine which Linux name belongs to which hardware device,
> especially with USB.
> 
> On the other hand, disk statistics should not be in
> /proc/partitions. They should be in /proc/diskstatistics.
> I see a heading today "rio rmerge rsect ruse wio wmerge"
> "wsect wuse running use aveq". No doubt next year we'll
> want different statistics. So /proc/diskstatistics should
> start with a header line including a version field.
> 
> Please keep these disk statistics apart from /proc/partitions.

The change can possibly break userlevel tools which were working with
2.4.18.

Christoph, please create a /proc/diskstatistics file or something like
that and send me a patch.

Thanks.