From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23097 invoked by alias); 27 Jul 2013 00:22:31 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 23088 invoked by uid 89); 27 Jul 2013 00:22:31 -0000 X-Spam-SWARE-Status: No, score=-4.3 required=5.0 tests=AWL,BAYES_50,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL,RDNS_NONE,SPF_HELO_PASS,SPF_PASS autolearn=no version=3.3.1 Received: from Unknown (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Sat, 27 Jul 2013 00:22:30 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6R0MNow020522 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 26 Jul 2013 20:22:23 -0400 Received: from fche.csb (vpn-49-4.rdu2.redhat.com [10.10.49.4]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r6R0MMZG012927; Fri, 26 Jul 2013 20:22:23 -0400 Received: by fche.csb (Postfix, from userid 2569) id 3E30D5816C; Fri, 26 Jul 2013 20:22:22 -0400 (EDT) Date: Sat, 27 Jul 2013 00:22:00 -0000 From: "Frank Ch. Eigler" To: Eric Wong Cc: Systemtap List Subject: Re: copy faults from user_string* functions Message-ID: <20130727002222.GB4664@redhat.com> References: <20130726063634.GA32443@dcvr.yhbt.net> <20130726175602.GA5773@dcvr.yhbt.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130726175602.GA5773@dcvr.yhbt.net> User-Agent: Mutt/1.4.2.2i X-SW-Source: 2013-q3/txt/msg00073.txt.bz2 Hi, Eric - On Fri, Jul 26, 2013 at 05:56:02PM +0000, Eric Wong wrote: > [...] > Is there any optional way to get stap to trigger page faults to get > that data? Not easily. Perhaps from the tracing site, the code could load a few bytes of the strings whose addresses are being passed. Perhaps try an mlock() or some other explicit data-segment-dereference loop during program startup? > When tracing, losing a little performance is OK, especially with > cmogstored (which is entirely network/disk bound). Understood. - FChE