Re: Soliciting opinions on dsched removal

Markus Pfeiffer <[email protected]> Mon, 9 Nov 2015 00:09:36 +0000
Newsgroups gmane.os.dragonfly-bsd.kernel
Message-ID <[email protected]>
Hi,

On Sun, Nov 08, 2015 at 05:03:33PM -0500, Alex Hornung wrote:
> On 08/11/2015 10:38, Matthew Dillon wrote:
> >     The basic problem is that heavy use of dsched (the disk scheduler) has
> >     caused crashes and lockups ever since dsched went into the tree, and is
> >     still causing crashes and lockups today.  Several people have tried to 
> >     bandaid it but honestly I think the only correct solution is to remove it
> >     and then start over from scratch at some future date with a better design.
> >
> >     So I would like to remove it, and I am soliciting opinions on that.
> I'm all for it.

I am completely with Alex on this one, in particular the comments about SSD,
and probably even more so NVMe warrant changing the approach to IO scheduling.
In particular simplifying the CAM interface seems worth a shot.

Not that I want to stop anyone from trying...

Cheers,
Markus
signature.asc (application/pgp-signature, 819 B)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
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=d3LY
-----END PGP SIGNATURE-----