From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43BF2D03.2030908@yahoo.com.au> Date: Sat, 07 Jan 2006 13:52:51 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [PATCH] use local_t for page statistics References: <20060106215332.GH8979@kvack.org> <20060106163313.38c08e37.akpm@osdl.org> In-Reply-To: <20060106163313.38c08e37.akpm@osdl.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Benjamin LaHaise , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Andrew Morton wrote: > Benjamin LaHaise 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. Send instant messages to your online friends http://au.messenger.yahoo.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org