From nobody Tue May 7 00:48:48 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1493054482259474.7352474837203; Mon, 24 Apr 2017 10:21:22 -0700 (PDT) Received: from localhost ([::1]:45232 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2hfs-00084F-Ar for importer@patchew.org; Mon, 24 Apr 2017 13:21:20 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44386) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2hey-0007g7-1z for qemu-devel@nongnu.org; Mon, 24 Apr 2017 13:20:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d2heu-0003Js-P2 for qemu-devel@nongnu.org; Mon, 24 Apr 2017 13:20:23 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:60615) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d2heu-0003JU-GY for qemu-devel@nongnu.org; Mon, 24 Apr 2017 13:20:20 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v3OHIoMv052793 for ; Mon, 24 Apr 2017 13:20:18 -0400 Received: from e24smtp05.br.ibm.com (e24smtp05.br.ibm.com [32.104.18.26]) by mx0a-001b2d01.pphosted.com with ESMTP id 2a1j7647mg-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 24 Apr 2017 13:20:18 -0400 Received: from localhost by e24smtp05.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Apr 2017 14:20:15 -0300 Received: from d24relay04.br.ibm.com (9.18.232.146) by e24smtp05.br.ibm.com (10.172.0.141) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 24 Apr 2017 14:20:14 -0300 Received: from d24av03.br.ibm.com (d24av03.br.ibm.com [9.8.31.95]) by d24relay04.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v3OHKENR917854 for ; Mon, 24 Apr 2017 14:20:14 -0300 Received: from d24av03.br.ibm.com (localhost [127.0.0.1]) by d24av03.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v3OHKEi9006635 for ; Mon, 24 Apr 2017 14:20:15 -0300 Received: from pacoca.ibm.com ([9.85.159.201]) by d24av03.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id v3OHKBpW006582; Mon, 24 Apr 2017 14:20:12 -0300 From: Jose Ricardo Ziviani To: qemu-devel@nongnu.org Date: Mon, 24 Apr 2017 14:19:58 -0300 X-Mailer: git-send-email 2.7.4 X-TM-AS-MML: disable x-cbid: 17042417-0032-0000-0000-000005578FF7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17042417-0033-0000-0000-000011DCCA1E Message-Id: <1493054398-26013-1-git-send-email-joserz@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-04-24_14:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1704240295 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH v2] trace: add qemu mutex lock and unlock trace events X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, famz@redhat.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" These trace events were very useful to help me to understand and find a reordering issue in vfio, for example: qemu_mutex_lock locked mutex 0x10905ad8 vfio_region_write (0001:03:00.0:region1+0xc0, 0x2020c, 4) qemu_mutex_unlock unlocked mutex 0x10905ad8 qemu_mutex_lock locked mutex 0x10905ad8 vfio_region_write (0001:03:00.0:region1+0xc4, 0xa0000, 4) qemu_mutex_unlock unlocked mutex 0x10905ad8 that also helped me to see the desired result after the fix: qemu_mutex_lock locked mutex 0x10905ad8 vfio_region_write (0001:03:00.0:region1+0xc0, 0x2000c, 4) vfio_region_write (0001:03:00.0:region1+0xc4, 0xb0000, 4) qemu_mutex_unlock unlocked mutex 0x10905ad8 So it could be a good idea to have these traces implemented. It's worth mentioning that they should be surgically enabled during the debugging, otherwise it can flood the trace logs with lock/unlock messages. How to use it: trace-event qemu_mutex_lock on|off trace-event qemu_mutex_unlock on|off or trace-event qemu_mutex* on|off Signed-off-by: Jose Ricardo Ziviani Reviewed-by: Fam Zheng Reviewed-by: Jose Ricardo Ziviani --- v2: - removed unecessary (void*) cast - renamed parameter name to lock instead of qemu_global_mutex util/qemu-thread-posix.c | 5 +++++ util/trace-events | 4 ++++ 2 files changed, 9 insertions(+) diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index 73e3a0e..4f77d7b 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -14,6 +14,7 @@ #include "qemu/thread.h" #include "qemu/atomic.h" #include "qemu/notify.h" +#include "trace.h" =20 static bool name_threads; =20 @@ -60,6 +61,8 @@ void qemu_mutex_lock(QemuMutex *mutex) err =3D pthread_mutex_lock(&mutex->lock); if (err) error_exit(err, __func__); + + trace_qemu_mutex_lock(&mutex->lock); } =20 int qemu_mutex_trylock(QemuMutex *mutex) @@ -74,6 +77,8 @@ void qemu_mutex_unlock(QemuMutex *mutex) err =3D pthread_mutex_unlock(&mutex->lock); if (err) error_exit(err, __func__); + + trace_qemu_mutex_unlock(&mutex->lock); } =20 void qemu_rec_mutex_init(QemuRecMutex *mutex) diff --git a/util/trace-events b/util/trace-events index b44ef4f..70f6212 100644 --- a/util/trace-events +++ b/util/trace-events @@ -55,3 +55,7 @@ lockcnt_futex_wait_prepare(const void *lockcnt, int expec= ted, int new) "lockcnt lockcnt_futex_wait(const void *lockcnt, int val) "lockcnt %p waiting on %d" lockcnt_futex_wait_resume(const void *lockcnt, int new) "lockcnt %p after = wait: %d" lockcnt_futex_wake(const void *lockcnt) "lockcnt %p waking up one waiter" + +# util/qemu-thread-posix.c +qemu_mutex_lock(void *lock) "locked mutex %p" +qemu_mutex_unlock(void *lock) "unlocked mutex %p" --=20 2.7.4