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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 02617C282C4 for ; Mon, 4 Feb 2019 08:59:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C503C214DA for ; Mon, 4 Feb 2019 08:59:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728782AbfBDI7S (ORCPT ); Mon, 4 Feb 2019 03:59:18 -0500 Received: from terminus.zytor.com ([198.137.202.136]:37791 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726987AbfBDI7R (ORCPT ); Mon, 4 Feb 2019 03:59:17 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x148wqC1358434 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 4 Feb 2019 00:58:52 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x148wqqc358431; Mon, 4 Feb 2019 00:58:52 -0800 Date: Mon, 4 Feb 2019 00:58:52 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Waiman Long Message-ID: Cc: bp@alien8.de, peterz@infradead.org, torvalds@linux-foundation.org, paulmck@linux.vnet.ibm.com, hpa@zytor.com, james.morse@arm.com, longman@redhat.com, zhenzhong.duan@oracle.com, will.deacon@arm.com, mingo@kernel.org, akpm@linux-foundation.org, srinivas.eeda@oracle.com, linux-kernel@vger.kernel.org, tglx@linutronix.de Reply-To: longman@redhat.com, mingo@kernel.org, will.deacon@arm.com, zhenzhong.duan@oracle.com, hpa@zytor.com, james.morse@arm.com, paulmck@linux.vnet.ibm.com, bp@alien8.de, peterz@infradead.org, torvalds@linux-foundation.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, srinivas.eeda@oracle.com In-Reply-To: <1548798828-16156-3-git-send-email-longman@redhat.com> References: <1548798828-16156-3-git-send-email-longman@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:locking/core] locking/qspinlock_stat: Track the no MCS node available case Git-Commit-ID: 412f34a82ccf7dd52f6b197f6450a33f03342523 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 412f34a82ccf7dd52f6b197f6450a33f03342523 Gitweb: https://git.kernel.org/tip/412f34a82ccf7dd52f6b197f6450a33f03342523 Author: Waiman Long AuthorDate: Tue, 29 Jan 2019 22:53:46 +0100 Committer: Ingo Molnar CommitDate: Mon, 4 Feb 2019 09:03:30 +0100 locking/qspinlock_stat: Track the no MCS node available case Track the number of slowpath locking operations that are being done without any MCS node available as well renaming lock_index[123] to make them more descriptive. Using these stat counters is one way to find out if a code path is being exercised. Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Borislav Petkov Cc: H. Peter Anvin Cc: James Morse Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: SRINIVAS Cc: Thomas Gleixner Cc: Will Deacon Cc: Zhenzhong Duan Link: https://lkml.kernel.org/r/1548798828-16156-3-git-send-email-longman@redhat.com Signed-off-by: Ingo Molnar --- kernel/locking/qspinlock.c | 3 ++- kernel/locking/qspinlock_stat.h | 21 +++++++++++++++------ 2 files changed, 17 insertions(+), 7 deletions(-) diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 0875053c4050..21ee51b47961 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -422,6 +422,7 @@ pv_queue: * simple enough. */ if (unlikely(idx >= MAX_NODES)) { + qstat_inc(qstat_lock_no_node, true); while (!queued_spin_trylock(lock)) cpu_relax(); goto release; @@ -432,7 +433,7 @@ pv_queue: /* * Keep counts of non-zero index values: */ - qstat_inc(qstat_lock_idx1 + idx - 1, idx); + qstat_inc(qstat_lock_use_node2 + idx - 1, idx); /* * Ensure that we increment the head node->count before initialising diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h index 42d3d8dc8f49..d73f85388d5c 100644 --- a/kernel/locking/qspinlock_stat.h +++ b/kernel/locking/qspinlock_stat.h @@ -30,6 +30,13 @@ * pv_wait_node - # of vCPU wait's at a non-head queue node * lock_pending - # of locking operations via pending code * lock_slowpath - # of locking operations via MCS lock queue + * lock_use_node2 - # of locking operations that use 2nd per-CPU node + * lock_use_node3 - # of locking operations that use 3rd per-CPU node + * lock_use_node4 - # of locking operations that use 4th per-CPU node + * lock_no_node - # of locking operations without using per-CPU node + * + * Subtracting lock_use_node[234] from lock_slowpath will give you + * lock_use_node1. * * Writing to the "reset_counters" file will reset all the above counter * values. @@ -55,9 +62,10 @@ enum qlock_stats { qstat_pv_wait_node, qstat_lock_pending, qstat_lock_slowpath, - qstat_lock_idx1, - qstat_lock_idx2, - qstat_lock_idx3, + qstat_lock_use_node2, + qstat_lock_use_node3, + qstat_lock_use_node4, + qstat_lock_no_node, qstat_num, /* Total number of statistical counters */ qstat_reset_cnts = qstat_num, }; @@ -85,9 +93,10 @@ static const char * const qstat_names[qstat_num + 1] = { [qstat_pv_wait_node] = "pv_wait_node", [qstat_lock_pending] = "lock_pending", [qstat_lock_slowpath] = "lock_slowpath", - [qstat_lock_idx1] = "lock_index1", - [qstat_lock_idx2] = "lock_index2", - [qstat_lock_idx3] = "lock_index3", + [qstat_lock_use_node2] = "lock_use_node2", + [qstat_lock_use_node3] = "lock_use_node3", + [qstat_lock_use_node4] = "lock_use_node4", + [qstat_lock_no_node] = "lock_no_node", [qstat_reset_cnts] = "reset_counters", };