On Wed, Jun 30, 2010 at 10:40:49PM +1000, Nick Piggin wrote: > But actually it's not all for scalability. I have some follow on patches > (that require RCU inodes, among other things) that actually improve > single threaded performance significnatly. git diff workload IIRC was > several % improved from speeding up stat(2). I rewrote the store-free path walk patch that goes on top of this patchset (it's now much cleaner and more optimised, I'll post a patch soonish). It is quicker than I remembered. A single thread running stat(2) in a loop on a file "./file" has the following cost (on an 2s8c Barcelona): 2.6.35-rc3 595 ns/op patched 336 ns/op stat(2) takes 56% the time with patches. It's something like 13 fewer atomic operations per syscall. What's that good for? A single threaded, cached `git diff` on the linux kernel tree takes just 81% of the time after the vfs patches (0.27s vs 0.33s). -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
