From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7075 invoked by alias); 2 Nov 2014 12:40:43 -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 7067 invoked by uid 89); 2 Nov 2014 12:40:42 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.6 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: e23smtp01.au.ibm.com Received: from e23smtp01.au.ibm.com (HELO e23smtp01.au.ibm.com) (202.81.31.143) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Sun, 02 Nov 2014 12:40:40 +0000 Received: from /spool/local by e23smtp01.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Sun, 2 Nov 2014 22:40:33 +1000 Received: from d23relay06.au.ibm.com (d23relay06.au.ibm.com [9.185.63.219]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id CBD062CE8047 for ; Sun, 2 Nov 2014 23:40:31 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay06.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sA2CeKUu38731890 for ; Sun, 2 Nov 2014 23:40:20 +1100 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sA2CeTXV030566 for ; Sun, 2 Nov 2014 23:40:30 +1100 Received: from [192.168.122.32] ([9.79.176.179]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id sA2CeJw9030473; Sun, 2 Nov 2014 23:40:26 +1100 Subject: [PATCH v4 0/5] perf/sdt: SDT events listing/probing To: linux-kernel@vger.kernel.org From: Hemant Kumar Cc: srikar@linux.vnet.ibm.com, peterz@infradead.org, oleg@redhat.com, hegdevasant@linux.vnet.ibm.com, mingo@redhat.com, anton@redhat.com, systemtap@sourceware.org, namhyung@kernel.org, masami.hiramatsu.pt@hitachi.com, aravinda@linux.vnet.ibm.com, penberg@iki.fi Date: Sun, 02 Nov 2014 12:40:00 -0000 Message-ID: <20141102105006.21708.28734.stgit@hemant-fedora> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14110212-1618-0000-0000-0000012CE726 X-SW-Source: 2014-q4/txt/msg00088.txt.bz2 This patchset helps in listing dtrace style markers(SDT) present in user space applications through perf. Notes/markers are placed at important places by the developers. They have a negligible overhead when not enabled. We can enable them and probe at these places and find some important information like the arguments' values, etc. We have lots of applications which use SDT markers today, like: Postgresql, MySql, Mozilla, Perl, Python, Java, Ruby, libvirt, QEMU, glib To add SDT markers into user applications: We need to have this header sys/sdt.h present. sys/sdt.h used is version 3. If not present, install systemtap-sdt-devel package (for fedora-20). With this patchset, - Use perf sdt-cache --add to add SDT events to a cache. # perf sdt-cache --add ./user_app 4 SDT events added for /home/user/user_app! - Use perf sdt-cache --del to remove SDT events from the cache> # perf sdt-cache --del ./user_app 4 events removed for /home/user/user_app! - Dump the cache onto stdout using perf sdt-cache --dump: # perf sdt-cache --dump /home/user/user_app : %user_app:foo_start %user_app:fun_start - To probe and trace an SDT event : # perf record -e %user_app:foo_start -aR sleep 10 The support for perf to sdt events has undergone a lot of changes since it was introduced. After a lot of discussions (https://lkml.org/lkml/2014/7/20/284), the patchset is subdivided for ease of review. Previously, a patchset supporting "perf list sdt" was posted, but it didn't make much sense since, only listing SDT events for an ELF won't help. This patchset aims at adding a sub-command "sdt-cache" to perf to manage a cache for management of the SDT events. This link shows an example of marker probing with Systemtap: https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps This link provides important info regarding SDT notes: http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation - Markers in binaries : These SDT markers are present in the ELF in the section named ".note.stapsdt". Here, the name of the marker, its provider, type, location, base address, semaphore address. We can retrieve these values using the members name_off and desc_off in Nhdr structure. If these are not enabled, they are present in the ELF as nop. Changes since last series: - Changed to use the new --quiet option added by Masami to silently add/delete SDT events for "perf record". - Now, the options are used with 'PARSE_OPT_EXCLUSIVE' added by Namhyung Kim. - Addressed the other review comments made by Masami and Namhyung. - Fixed some bugs. TODO: - Add support to add most of the SDT events on a system to the cache. - Recognizing arguments and support to probe on them. --- Hemant Kumar (5): perf/sdt: ELF support for SDT perf/sdt: Add SDT events into a cache perf/sdt: Show SDT cache contents perf/sdt: Delete SDT events from cache perf/sdt: Add support to perf record to trace SDT events tools/perf/Documentation/perf-sdt-cache.txt | 36 + tools/perf/Makefile.perf | 4 tools/perf/builtin-probe.c | 5 tools/perf/builtin-record.c | 23 + tools/perf/builtin-sdt-cache.c | 104 +++ tools/perf/builtin.h | 1 tools/perf/command-list.txt | 1 tools/perf/perf.c | 1 tools/perf/util/parse-events.c | 6 tools/perf/util/parse-events.h | 7 tools/perf/util/probe-event.c | 85 ++- tools/perf/util/probe-event.h | 8 tools/perf/util/probe-finder.c | 3 tools/perf/util/sdt.c | 899 +++++++++++++++++++++++++++ tools/perf/util/symbol-elf.c | 252 ++++++++ tools/perf/util/symbol.h | 23 + 16 files changed, 1448 insertions(+), 10 deletions(-) create mode 100644 tools/perf/Documentation/perf-sdt-cache.txt create mode 100644 tools/perf/builtin-sdt-cache.c create mode 100644 tools/perf/util/sdt.c --