From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 465FCC46470 for ; Thu, 9 Aug 2018 04:24:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAC94217AE for ; Thu, 9 Aug 2018 04:24:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAC94217AE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728091AbeHIGrA (ORCPT ); Thu, 9 Aug 2018 02:47:00 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:36498 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727579AbeHIGq7 (ORCPT ); Thu, 9 Aug 2018 02:46:59 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w794JFEC108412 for ; Thu, 9 Aug 2018 00:24:09 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2krdcrt6s3-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 09 Aug 2018 00:24:08 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 9 Aug 2018 05:19:02 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w794J1Db37159012 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 9 Aug 2018 04:19:01 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0E3DBA4059; Thu, 9 Aug 2018 07:19:08 +0100 (BST) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C5D65A4051; Thu, 9 Aug 2018 07:19:04 +0100 (BST) Received: from bangoria.in.ibm.com (unknown [9.124.35.190]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 9 Aug 2018 07:19:04 +0100 (BST) From: Ravi Bangoria To: srikar@linux.vnet.ibm.com, oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, liu.song.a23@gmail.com Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, linux-kernel@vger.kernel.org, ananth@linux.vnet.ibm.com, alexis.berlemont@gmail.com, naveen.n.rao@linux.vnet.ibm.com, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux@armlinux.org.uk, ralf@linux-mips.org, paul.burton@mips.com, Ravi Bangoria Subject: [PATCH v8 0/6] Uprobes: Support SDT markers having reference count (semaphore) Date: Thu, 9 Aug 2018 09:48:50 +0530 X-Mailer: git-send-email 2.14.4 X-TM-AS-GCONF: 00 x-cbid: 18080904-0016-0000-0000-000001F433EE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18080904-0017-0000-0000-0000324A449E Message-Id: <20180809041856.1547-1-ravi.bangoria@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-09_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808090045 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org v8 changes: - Call delayed_uprobe_remove(uprobe, NULL) from put_uprobe() as well. - Other minor optimizations. v7: https://lkml.org/lkml/2018/7/31/20 Description: Userspace Statically Defined Tracepoints[1] are dtrace style markers inside userspace applications. Applications like PostgreSQL, MySQL, Pthread, Perl, Python, Java, Ruby, Node.js, libvirt, QEMU, glib etc have these markers embedded in them. These markers are added by developer at important places in the code. Each marker source expands to a single nop instruction in the compiled code but there may be additional overhead for computing the marker arguments which expands to couple of instructions. In case the overhead is more, execution of it can be omitted by runtime if() condition when no one is tracing on the marker: if (reference_counter > 0) { Execute marker instructions; } Default value of reference counter is 0. Tracer has to increment the reference counter before tracing on a marker and decrement it when done with the tracing. Currently, perf tool has limited supports for SDT markers. I.e. it can not trace markers surrounded by reference counter. Also, it's not easy to add reference counter logic in userspace tool like perf, so basic idea for this patchset is to add reference counter logic in the a uprobe infrastructure. Ex,[2] # cat tick.c ... for (i = 0; i < 100; i++) { DTRACE_PROBE1(tick, loop1, i); if (TICK_LOOP2_ENABLED()) { DTRACE_PROBE1(tick, loop2, i); } printf("hi: %d\n", i); sleep(1); } ... Here tick:loop1 is marker without reference counter where as tick:loop2 is surrounded by reference counter condition. # perf buildid-cache --add /tmp/tick # perf probe sdt_tick:loop1 # perf probe sdt_tick:loop2 # perf stat -e sdt_tick:loop1,sdt_tick:loop2 -- /tmp/tick hi: 0 hi: 1 hi: 2 ^C Performance counter stats for '/tmp/tick': 3 sdt_tick:loop1 0 sdt_tick:loop2 2.747086086 seconds time elapsed Perf failed to record data for tick:loop2. Same experiment with this patch series: # ./perf buildid-cache --add /tmp/tick # ./perf probe sdt_tick:loop2 # ./perf stat -e sdt_tick:loop2 /tmp/tick hi: 0 hi: 1 hi: 2 ^C Performance counter stats for '/tmp/tick': 3 sdt_tick:loop2 2.561851452 seconds time elapsed [1] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation Ravi Bangoria (6): Uprobes: Simplify uprobe_register() body Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Uprobes: Support SDT markers having reference count (semaphore) Uprobes/sdt: Prevent multiple reference counter for same uprobe trace_uprobe/sdt: Prevent multiple reference counter for same uprobe perf probe: Support SDT markers having reference counter (semaphore) arch/arm/probes/uprobes/core.c | 2 +- arch/mips/kernel/uprobes.c | 2 +- include/linux/uprobes.h | 7 +- kernel/events/uprobes.c | 329 +++++++++++++++++++++++++++++++++++------ kernel/trace/trace.c | 2 +- kernel/trace/trace_uprobe.c | 75 +++++++++- tools/perf/util/probe-event.c | 39 ++++- tools/perf/util/probe-event.h | 1 + tools/perf/util/probe-file.c | 34 ++++- tools/perf/util/probe-file.h | 1 + tools/perf/util/symbol-elf.c | 46 ++++-- tools/perf/util/symbol.h | 7 + 12 files changed, 472 insertions(+), 73 deletions(-) -- 2.14.4