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 AE9F1C43142 for ; Tue, 31 Jul 2018 03:51:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63A30208A2 for ; Tue, 31 Jul 2018 03:51:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63A30208A2 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 S1728289AbeGaFaH (ORCPT ); Tue, 31 Jul 2018 01:30:07 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48174 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726389AbeGaFaH (ORCPT ); Tue, 31 Jul 2018 01:30:07 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w6V3nMl8020421 for ; Mon, 30 Jul 2018 23:51:55 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0b-001b2d01.pphosted.com with ESMTP id 2kjc8sfjfb-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 30 Jul 2018 23:51:55 -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) Tue, 31 Jul 2018 04:51:48 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w6V3pliJ31654108 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 31 Jul 2018 03:51:47 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5001B4C046; Tue, 31 Jul 2018 06:52:00 +0100 (BST) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 05A794C044; Tue, 31 Jul 2018 06:51:57 +0100 (BST) Received: from bangoria.in.ibm.com (unknown [9.124.31.37]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 31 Jul 2018 06:51:56 +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 v7 0/6] Uprobes: Support SDT markers having reference count (semaphore) Date: Tue, 31 Jul 2018 09:21:37 +0530 X-Mailer: git-send-email 2.14.4 X-TM-AS-GCONF: 00 x-cbid: 18073103-0016-0000-0000-000001EE812B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18073103-0017-0000-0000-000032439D9A Message-Id: <20180731035143.11942-1-ravi.bangoria@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-07-31_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=8.0.1-1806210000 definitions=main-1807310041 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org v7 changes: - Don't allow both zero and non-zero reference counter offset at the same time. It's painful and error prone. - Don't call delayed_uprobe_install() if vma->vm_mm does not have any breakpoint installed. v6: https://lkml.org/lkml/2018/7/16/353 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 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 | 315 +++++++++++++++++++++++++++++++++++------ 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, 459 insertions(+), 72 deletions(-) -- 2.14.4