Messages in this thread |  | | | Date | Fri, 18 May 2001 21:25:31 +0200 | | From | Jens Axboe <> | | Subject | Re: DVD blockdevice buffers |
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On Fri, May 18 2001, Eduard Hasenleithner wrote: > I have a problem with the buffering mechanism of my blockdevice, > namely a ide_scsi DVD-ROM drive. After inserting a DVD and reading > data linearly from the DVD, an excessive amount of buffer memory gets > allocated. > > This can easily be reproduced with > cat /dev/sr0 > /dev/null > > Remember, nearly the same task is carried out when playing a DVD. > > As a result the system performance goes down. I'm still able to use > my applications, but es every single piece of unused memory is swapped > out, and swapping in costs a certain amount of time.
That's why streaming media applications like a dvd player should use raw I/O -- to bypass system cache. See /dev/raw*
-- Jens Axboe
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