Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH] [RFC] Optimize select/poll by putting small data sets on the stack | Date | Wed, 4 Jan 2006 00:28:40 +0000 |
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On Tuesday 03 January 2006 20:58, Andi Kleen wrote: > > This is a RFC for now. I would be interested in testing > feedback. Patch is for 2.6.15. > > Optimize select and poll by a using stack space for small fd sets > > This brings back an old optimization from Linux 2.0. Using > the stack is faster than kmalloc. On a Intel P4 system > it speeds up a select of a single pty fd by about 13% > (~4000 cycles -> ~3500)
Hmm, can you include the same change for compat_sys_select()? When that was introduced, sys_select and compat_sys_select were basically identical in their code, which makes it a lot easier to verify that the compat_ version is correct.
Interestingly, doing a diff between sys_select and compat_sys_select in the current kernel seems to suggest that they are both buggy in that they miss checks for failing __put_user, but in /different/ places.
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