Re: cdrom changes in test13-pre2 slow down cdrom access by 70%

Jens Axboe
2000-12-27T06:08:57Z

On Tue, Dec 26 2000, David Mansfield wrote:
> > > > The cdrom changes that went into test13-pre2 really kill the performance
> > > > of my cdrom. I'm using cdparanoia to read audio data, and it normally
>
> ... cut ...
>
> > Anyway, do you think a 'try to allocate 8, if that fails, try to
> > allocate 1' solution would be a simple compromise? That should be easy
> > to do, based on the above code (if kmalloc returns NULL && frames > 1,
> > frames = 1, retry...).
> >
>
> Jens,
>
> Here's a version of the above idea, ontop of the patch you sent. It's
> cut and pasted, but I don't think it's whitespace mangled... I haven't
> actually run with this patch, but it does compile :-)

In principle it looks ok, but after some time we are bound to fail 8
frame allocations anyway and this patch won't help. For the modular
case, preallocation of a bigger chunk at init time is no good either.
Builtin would be fine of course. This almost screams sg to me :-)

--
* Jens Axboe <axboe@suse.de>
* SuSE Labs