Date: Wed, 7 Jul 2004 16:17:27 -0600 (MDT) From: Scott Long <scottl@freebsd.org> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Julian Elischer <julian@elischer.org> Subject: Re: speeding up ugen by an order of magnitude. Message-ID: <20040707161618.V97786@pooker.samsco.org> In-Reply-To: <1901.1089236059@critter.freebsd.dk>
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On Wed, 7 Jul 2004, Poul-Henning Kamp wrote: > In message <200407072129.15095.mycroft@netbsd.org>, "Charles M. Hannum" writes: > >On Wednesday 07 July 2004 20:46, Charles M. Hannum wrote: > >> 1) You'll need to add an interface for assigning pipes for read and write, > >> since there may be more than just bulk pipes (and may be more than one bulk > >> pipe in each direction), and we only have have device node to work with. > > > >Seems I misspoke there. That part looks fine. > > > >I think you're going to be screwed by the buffer alignment, though. This also > >causes some issues with umass if you're not using a bounce buffer. > > We've already had that issue with ATA for the børked Geode controller: > physio does nothing for alignment and relies on userland doing something > sensible. > > I think this is pretty reasonable for the kind of hardware-near > work that physio is usually employed in (including if we use it for > ugen). > > Obviously, if the alignment is not OK, EINVAL should be returned, > and that means that the driver should explicitly check the alignment. Note that busdma can handle alignment now for loaded buffers by using bounce pages. Scotthome | help
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