On Fri, 25 May 2012, Salvo Tomaselli wrote: > > Because paging out a couple Gigabytes is veeeeeery different from > > writing a couple Gigabytes to disk, of course. > > Yes because writing that on disk will only block the thread performing the > write, not every thread that tries to allocate memory.
What IO scheduler are you using? It must not be CFQ. CFQ will happly screw it up and stall both readers and writers when the number of dirty pages gets too large (which will happen if you write a gigabyte file to disk). Either that, or you're cheating and your backend devices are simply "fast enough" that it doesn't matter (fast RAID or fast SSD). The real question is: what does it better under CFQ+IO contention? Several threads doing filesystem IO, or the swapper? Hint: it is not an easy question to answer because it depends on the load, type of load, and backend device. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20120525102037.gc6...@khazad-dum.debian.net
