From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id D7BE46B01E3 for ; Mon, 5 Apr 2010 17:19:19 -0400 (EDT) Message-ID: <4BBA53A0.8050608@redhat.com> Date: Tue, 06 Apr 2010 00:18:24 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [PATCH 00 of 41] Transparent Hugepage Support #17 References: <20100405120906.0abe8e58.akpm@linux-foundation.org> <20100405193616.GA5125@elte.hu> <20100405210133.GE21620@think> In-Reply-To: <20100405210133.GE21620@think> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Chris Mason Cc: Linus Torvalds , Pekka Enberg , Ingo Molnar , Andrew Morton , Andrea Arcangeli , linux-mm@kvack.org, Marcelo Tosatti , Adam Litke , Izik Eidus , Hugh Dickins , Nick Piggin , Rik van Riel , Mel Gorman , Dave Hansen , Benjamin Herrenschmidt , Mike Travis , KAMEZAWA Hiroyuki , Christoph Lameter , Chris Wright , bpicco@redhat.com, KOSAKI Motohiro , Balbir Singh , Arnd Bergmann , "Michael S. Tsirkin" , Peter Zijlstra , Johannes Weiner , Daisuke Nishimura List-ID: On 04/06/2010 12:01 AM, Chris Mason wrote: > On Mon, Apr 05, 2010 at 01:32:21PM -0700, Linus Torvalds wrote: > >> >> On Mon, 5 Apr 2010, Pekka Enberg wrote: >> >>> AFAIK, most modern GCs split memory in young and old generation >>> "zones" and _copy_ surviving objects from the former to the latter if >>> their lifetime exceeds some threshold. The JVM keeps scanning the >>> smaller young generation very aggressively which causes TLB pressure >>> and scans the larger old generation less often. >>> >> .. my only input to this is: numbers talk, bullsh*t walks. >> >> I'm not interested in micro-benchmarks, either. I can show infinite TLB >> walk improvement in a microbenchmark. >> > Ok, I'll bite. I should be able to get some database workloads with > hugepages, transparent hugepages, and without any hugepages at all. > Please run them in conjunction with Mel Gorman's memory compaction, otherwise fragmentation may prevent huge pages from being instantiated. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- 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