Messages in this thread |  | | | Date | Wed, 06 Feb 2008 11:53:19 -0800 | | From | "H. Peter Anvin" <> | | Subject | Re: What is the limit size of tmpfs /dev/shm ? |
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Hugh Dickins wrote: > > In theory, yes, and should be true in practice before it hits swap. > But I think you'll find our swap handling is too primitive for tmpfs > to perform well once we hit swap. Most filesystems pay considerable > attention to good performance within their constraints of correctness. > Whereas with tmpfs we've just never worried about the performance once > swapping. It's used so you don't lose your data, but if you're really > expecting to be going to disk very much, better start with a filesystem > really designed for that. >
That sounds like a problem in our overall swap handling, not specifically in tmpfs. Now, I can't say anything concrete about heavy swap conditions, but in light swap conditions I have measured a 20x performance improvement(!) over ext3 on real workloads.
-hpa
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