Messages in this thread | | | Date | Tue, 16 Mar 1999 00:40:57 +0100 (CET) | From | Rik van Riel <> | Subject | Re: [patch] Re: MP3 skippety skip skipageness |
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On Sat, 13 Mar 1999, Pavel Machek wrote:
> > am i correct that you carelessly volunteer as a guinea pig? :) I do not > > have a sound card installed now, but could you try the attached patch, > > does it change anything? Thanks, > > Do you believe that your patch helps when I make machine go 20meg onto > swap? I _really_ don't think so, so I'm not testing it.
Being 20 megs into swap (and actively using it) might be a bit extreme, yes...
Now about the patch:
> [this is not my patch. Ingo wrote it.] > --- linux/drivers/block/ll_rw_blk.c.orig Fri Mar 12 10:31:53 1999 > +++ linux/drivers/block/ll_rw_blk.c Fri Mar 12 10:32:05 1999 > @@ -536,7 +536,7 @@ > > /* if no request available: if rw_ahead, forget it; otherwise try again blocking.. */ > if (!req) { > - if (rw_ahead) > + if (0 && rw_ahead) > goto end_io; > req = __get_request_wait(max_req, bh->b_rdev); > }
I really don't believen that this patch is correct, or even that it's very much better than the original (clearly braindead) code.
With the (very) agressive readahead we're doing now, a request queue of 64 entries really won't be big enough any more. In fact, it'll only be big enough for 2 to 4 'actual' requests.
The real fix would be to either increase the number of requests to something more reasonable (say 128 or 256) and/or to be more intelligent about putting more disk sectors into one request...
Rik -- Open Source: you deserve to be in control of your data. +-------------------------------------------------------------------+ | Linux Memory Management site: http://humbolt.geo.uu.nl/Linux-MM/ | | Nederlandse Linux documentatie: http://www.nl.linux.org/ | +-------------------------------------------------------------------+
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