From mboxrd@z Thu Jan 1 00:00:00 1970 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Subject: RE: [patch 0/3] no MAX_ARG_PAGES -v2 Date: Wed, 13 Jun 2007 16:36:13 -0700 Message-ID: <617E1C2C70743745A92448908E030B2A01AF860A@scsmsx411.amr.corp.intel.com> In-Reply-To: <20070613100334.635756997@chello.nl> From: "Luck, Tony" Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra , linux-kernel@vger.kernel.org, parisc-linux@lists.parisc-linux.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Cc: Ollie Wild , Andrew Morton , Ingo Molnar , Andi Kleen List-ID: > This patch-set aims at removing the current limit on argv+env space aka. > MAX_ARG_PAGES. Running with this patch shows that /bin/bash has some unpleasant O(n^2) performance issues with long argument lists. I made a 1Mbyte file full of pathnames, then timed the execution of: $ /bin/echo `cat megabyte` | wc $ /bin/echo `cat megabyte megabyte` | wc etc. ... System time was pretty much linear as the arglist grew (and only got up to 0.144 seconds at 5Mbytes). But user time ~= real time (in seconds) looks like: 1 5.318 2 18.871 3 40.620 4 70.819 5 108.911 Above 5Mbytes, I started seeing problems. The line/word/char counts from "wc" started being "0 0 0". Not sure if this is a problem in "wc" dealing with a single line >5MBytes, or some other problem (possibly I was exceeding the per-process stack limit which is only 8MB on that machine). -Tony -- 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