Messages in this thread | | | Date | Tue, 24 Feb 2009 17:24:43 +0100 | From | Andi Kleen <> | Subject | Re: Performance regression in write() syscall |
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On Tue, Feb 24, 2009 at 07:52:34AM -0800, Linus Torvalds wrote: > > > On Tue, 24 Feb 2009, Nick Piggin wrote: > > > > > it does make some kind of sense to try to avoid the noncached versions for > > > small writes - because small writes tend to be for temp-files. > > > > I don't see the significance of a temp file. If the pagecache is truncated, > > then the cachelines remain dirty and so you can't avoid an eventual store > > back to RAM? > > No, because many small files end up being used as scratch-pads (think > shell script sequences etc), and get read back immediately again. Doing > non-temporal stores might just be bad simply because trying to play games > with caching may simply do the wrong thing.
I usually recommend to use shmfs for /tmp. Perhaps that should be done more widely.
BTW I got some upcomming patches to improve c_*_u() and memcpy on modern Intel x86 CPUs.
-Andi
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