From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 37317 invoked by alias); 10 Aug 2016 15:33:12 -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 37264 invoked by uid 89); 10 Aug 2016 15:33:12 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=no version=3.3.2 spammy=D*scylladb.com, aviscylladbcom, sk:avi@scy, U*avi X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 10 Aug 2016 15:33:02 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D8D853B72D; Wed, 10 Aug 2016 15:33:00 +0000 (UTC) Received: from fche.csb (vpn-55-67.rdu2.redhat.com [10.10.55.67]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u7AFX0JI011282; Wed, 10 Aug 2016 11:33:00 -0400 Received: by fche.csb (Postfix, from userid 2569) id 4C7DF58C3C; Wed, 10 Aug 2016 11:32:59 -0400 (EDT) To: Avi Kivity Cc: Mark Wielaard , David Smith , systemtap@sourceware.org Subject: Re: Some newbie questions References: <20160809112501.GK2508@stream> <91592a2a-7373-6a27-413c-cf4aca70cb76@scylladb.com> From: fche@redhat.com (Frank Ch. Eigler) Date: Wed, 10 Aug 2016 15:33:00 -0000 In-Reply-To: <91592a2a-7373-6a27-413c-cf4aca70cb76@scylladb.com> (Avi Kivity's message of "Tue, 9 Aug 2016 17:11:00 +0300") Message-ID: User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SW-Source: 2016-q3/txt/msg00152.txt.bz2 Avi Kivity writes: > [...] > I'm surprised this didn't come up before. Trying to find out why a > function which is usually fast and very rarely slow seems to be a good > fit for systemtap. Like this? https://sourceware.org/systemtap/examples/#profiling/fntimes.stp Note though that such analysis probably cannot be performed based only upon PC samples - or even backtrace samples. We seem to require trapping individual function entry/exit events. - FChE