Messages in this thread | | | Date | Sat, 07 Jan 2006 13:52:51 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH] use local_t for page statistics |
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Andrew Morton wrote: > Benjamin LaHaise <bcrl@kvack.org> wrote: > >>The patch below converts the mm page_states counters to use local_t. >>mod_page_state shows up in a few profiles on x86 and x86-64 due to the >>disable/enable interrupts operations touching the flags register. On >>both my laptop (Pentium M) and P4 test box this results in about 10 >>additional /bin/bash -c exit 0 executions per second (P4 went from ~759/s >>to ~771/s). Tested on x86 and x86-64. Oh, also add a pgcow statistic >>for the number of COW page faults. > > > Bah. I think this is a better approach than the just-merged > mm-page_state-opt.patch, so I should revert that patch first? >
No. On many load/store architectures there is no good way to do local_t, so something like ppc32 or ia64 just uses all atomic operations for local_t, and ppc64 uses 3 counters per-cpu thus tripling the cache footprint.
Nick
-- SUSE Labs, Novell Inc.
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