Messages in this thread | | | From | Denis Vlasenko <> | Subject | Re: O_DIRECT question | Date | Sat, 20 Jan 2007 17:36:22 +0100 |
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On Thursday 11 January 2007 18:13, Michael Tokarev wrote: > example, which isn't quite possible now from userspace. But as long as > O_DIRECT actually writes data before returning from write() call (as it > seems to be the case at least with a normal filesystem on a real block > device - I don't touch corner cases like nfs here), it's pretty much > THE ideal solution, at least from the application (developer) standpoint.
Why do you want to wait while 100 megs of data are being written? You _have to_ have threaded db code in order to not waste gobs of CPU time on UP + even with that you eat context switch penalty anyway.
I hope you agree that threaded code is not ideal performance-wise - async IO is better. O_DIRECT is strictly sync IO. -- vda - 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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