Messages in this thread | | | Subject | Re: Linux 2.6.17-rc2 | From | "Linh Dang" <> | Date | Thu, 20 Apr 2006 15:57:37 -0400 |
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Jens Axboe <axboe@suse.de> wrote:
> On Thu, Apr 20 2006, Linh Dang wrote: >> Jens Axboe <axboe@suse.de> wrote: >> >>> On Wed, Apr 19 2006, Linus Torvalds wrote: >>>> There are some other buffer management system calls that I >>>> haven't done yet (and when I say "I haven't done yet", I >>>> obviously mean "that I hope some other sucker will do for me, >>>> since I'm lazy"), but that are obvious future extensions: >>> >>> Well it's worked so far, hasn't it? :-) >>> >>>> - an ioctl/fcntl to set the maximum size of the buffer. Right now >>>> it's hardcoded to 16 "buffer entries" (which in turn are normally >>>> limited to one page each, although there's nothing that >>>> _requires_ that a buffer entry always be a page). >>> >>> This is on a TODO, but not very high up since I've yet to see a >>> case where the current 16 page limitation is an issue. I'm sure >>> something will come up eventually, but until then I'd rather not >>> bother. >> >> DVD burning! splicing those huge VOB files into the dvd device >> would be nice. And believe me, the current 16 entries of the pipe >> is nowhere enough to sustain burning at 8X avg speed or higher. >> >> It's a special case but it'd benefit a LOT of ppl ;-) > > (don't drop the cc list) > > DVD burning probably isn't a good splice fit, since you need to do > more than actually just point the device at the data. SG_IO is > already zero-copy as it maps the user data into the kernel without > copying, so there's very little room for improvement there to begin > with.
DVD burning on linux is mostly:
mkisofs .... | growisofs ....
Ideally, on mkisofs side, we'd be able to:
- write some data/padding into the pipe - splice a HUGE file into the pipe - write some data/padding into the pipe - splice a HUGE file into the pipe ...
On growisofs side, we'd be able to:
- send some commands - splice N MBs of data from the pipe to the driver - send some commands - splice M MBs of data from the pipe to the driver ...
What'd be nice is an ioctl to change the size of the pipe between mkisofs and growisofs.
-- Linh Dang - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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