From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f48.google.com (mail-pb0-f48.google.com [209.85.160.48]) by kanga.kvack.org (Postfix) with ESMTP id CDD336B00FE for ; Mon, 11 Nov 2013 16:09:31 -0500 (EST) Received: by mail-pb0-f48.google.com with SMTP id mc17so3423792pbc.35 for ; Mon, 11 Nov 2013 13:09:31 -0800 (PST) Received: from psmtp.com ([74.125.245.186]) by mx.google.com with SMTP id ll9si17338819pab.8.2013.11.11.13.09.29 for ; Mon, 11 Nov 2013 13:09:30 -0800 (PST) Received: by mail-ea0-f178.google.com with SMTP id a10so2430813eae.23 for ; Mon, 11 Nov 2013 13:09:27 -0800 (PST) Date: Mon, 11 Nov 2013 22:09:24 +0100 From: Ingo Molnar Subject: Re: [PATCH] mm: cache largest vma Message-ID: <20131111210924.GA19284@gmail.com> References: <1383337039.2653.18.camel@buesod1.americas.hpqcorp.net> <1383537862.2373.14.camel@buesod1.americas.hpqcorp.net> <20131104073640.GF13030@gmail.com> <1384143129.6940.32.camel@buesod1.americas.hpqcorp.net> <20131111120116.GA21291@gmail.com> <1384194271.6940.40.camel@buesod1.americas.hpqcorp.net> <20131111204702.GD18886@gmail.com> <1384203573.6940.67.camel@buesod1.americas.hpqcorp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1384203573.6940.67.camel@buesod1.americas.hpqcorp.net> Sender: owner-linux-mm@kvack.org List-ID: To: Davidlohr Bueso Cc: Linus Torvalds , Andrew Morton , Hugh Dickins , Michel Lespinasse , Mel Gorman , Rik van Riel , Guan Xuetao , "Chandramouleeswaran, Aswin" , Linux Kernel Mailing List , linux-mm , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker * Davidlohr Bueso wrote: > > Or is access to varied in the Oracle case that it's missing the cache > > all the time, because the rbtree causes many cachemisses as the > > separate nodes are accessed during an rb-walk? > > Similar to get_cycles(), is there anyway to quickly measure the amount > of executed instructions? Getting the IPC for the mmap_cache (this of > course is constant) and the treewalk could give us a nice overview of > the function's cost. I was thinking of stealing some perf-stat > functionality for this but didn't get around to it. Hopefully there's an > easier way... There's no such easy method I'm afraid (Frederic's probe based trigger facility will give us that and more - but it's not ready yet) - but you could try profiling the workload for significant cache-misses: perf record -e cache-misses ... I _think_ if it's really catastrophic cache-misses then the rbtree walk should light up on the perf radar like crazy. Thanks, Ingo -- 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