Messages in this thread | | | Date | Thu, 25 Jan 2007 23:45:38 +0300 | From | Michael Tokarev <> | Subject | Re: O_DIRECT question |
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Phillip Susi wrote: > Denis Vlasenko wrote: >> You mean "You can use aio_write" ? > > Exactly. You generally don't use O_DIRECT without aio. Combining the > two is what gives the big win.
Well, it's not only aio. Multithreaded I/O also helps alot -- all this, say, to utilize a raid array with many spindles.
But even single-threaded I/O but in large quantities benefits from O_DIRECT significantly, and I pointed this out before. It's like enabling a write cache on disk AND doing intensive random writes - the cache - surprizingly - slows whole thing down by 5..10%.
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