From patchwork Thu Apr 26 10:34:27 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 10365503 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2F0D0601BE for ; Thu, 26 Apr 2018 10:51:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1CF3522B27 for ; Thu, 26 Apr 2018 10:51:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 110D827031; Thu, 26 Apr 2018 10:51:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6EEE722B27 for ; Thu, 26 Apr 2018 10:51:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=3ELbW+rdzEo0jnmHo5mzf5eFgG4rlBRaQD7e88+ieTU=; b=VBOZhkc93Ge/m7FNTw8mbqZwhS N2Qp+lkTQ00s9tH4x/nnLClMCk5bP8RMBgzBHr6KJ9Mg2dWwvWLYz11LjJ3qCoNvdsoyzXzzKwi80 /p7zwZy9sbXAvK2DM58T4IpIeG7m0v9w8SambVxNNYm03LsTRHzBEFcbMGz8lDmGIYiGBhveTl2TL aNs3q140Y6vA4TV8IW0i90Y5VmZA1oA4i+XncPz688WF2lRiK3wZlIDx42eeo8c5/UDEyqmPKi/Df +Zofbr0UKnKW/sTxn7A3tvLKIRRID7i08BaVjwDwgtZT5oHNanOMEQ+0bwDn7n2henrjtmID5WV3v ys+aS8LA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fBeVB-0006H0-1F; Thu, 26 Apr 2018 10:51:49 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fBeET-000234-0m for linux-arm-kernel@lists.infradead.org; Thu, 26 Apr 2018 10:34:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 929981A09; Thu, 26 Apr 2018 03:34:10 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 63F0A3F77A; Thu, 26 Apr 2018 03:34:10 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id D7F681AE4F9F; Thu, 26 Apr 2018 11:34:29 +0100 (BST) From: Will Deacon To: linux-kernel@vger.kernel.org Subject: [PATCH v3 13/14] locking/qspinlock: Add stat tracking for pending vs slowpath Date: Thu, 26 Apr 2018 11:34:27 +0100 Message-Id: <1524738868-31318-14-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1524738868-31318-1-git-send-email-will.deacon@arm.com> References: <1524738868-31318-1-git-send-email-will.deacon@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180426_033433_360523_699AD77C X-CRM114-Status: GOOD ( 16.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peterz@infradead.org, boqun.feng@gmail.com, will.deacon@arm.com, longman@redhat.com, paulmck@linux.vnet.ibm.com, mingo@kernel.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Waiman Long Currently, the qspinlock_stat code tracks only statistical counts in the PV qspinlock code. However, it may also be useful to track the number of locking operations done via the pending code vs. the MCS lock queue slowpath for the non-PV case. The qspinlock stat code is modified to do that. The stat counter pv_lock_slowpath is renamed to lock_slowpath so that it can be used by both the PV and non-PV cases. Signed-off-by: Waiman Long --- kernel/locking/qspinlock.c | 14 +++++++++++--- kernel/locking/qspinlock_paravirt.h | 7 +------ kernel/locking/qspinlock_stat.h | 9 ++++++--- 3 files changed, 18 insertions(+), 12 deletions(-) diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 1e3ddc42135e..b39f341d831b 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -12,11 +12,11 @@ * GNU General Public License for more details. * * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P. - * (C) Copyright 2013-2014 Red Hat, Inc. + * (C) Copyright 2013-2014,2018 Red Hat, Inc. * (C) Copyright 2015 Intel Corp. * (C) Copyright 2015 Hewlett-Packard Enterprise Development LP * - * Authors: Waiman Long + * Authors: Waiman Long * Peter Zijlstra */ @@ -33,6 +33,11 @@ #include /* + * Include queued spinlock statistics code + */ +#include "qspinlock_stat.h" + +/* * The basic principle of a queue-based spinlock can best be understood * by studying a classic queue-based spinlock implementation called the * MCS lock. The paper below provides a good description for this kind @@ -295,7 +300,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) BUILD_BUG_ON(CONFIG_NR_CPUS >= (1U << _Q_TAIL_CPU_BITS)); if (pv_enabled()) - goto queue; + goto pv_queue; if (virt_spin_lock(lock)) return; @@ -348,6 +353,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * *,1,0 -> *,0,1 */ clear_pending_set_locked(lock); + qstat_inc(qstat_lock_pending, true); return; } @@ -363,6 +369,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * queuing. */ queue: + qstat_inc(qstat_lock_slowpath, true); +pv_queue: node = this_cpu_ptr(&mcs_nodes[0]); idx = node->count++; tail = encode_tail(smp_processor_id(), idx); diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 2dbad2f25480..25730b2ac022 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -56,11 +56,6 @@ struct pv_node { }; /* - * Include queued spinlock statistics code - */ -#include "qspinlock_stat.h" - -/* * Hybrid PV queued/unfair lock * * By replacing the regular queued_spin_trylock() with the function below, @@ -428,7 +423,7 @@ pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node) /* * Tracking # of slowpath locking operations */ - qstat_inc(qstat_pv_lock_slowpath, true); + qstat_inc(qstat_lock_slowpath, true); for (;; waitcnt++) { /* diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h index 4a30ef63c607..6bd78c0740fc 100644 --- a/kernel/locking/qspinlock_stat.h +++ b/kernel/locking/qspinlock_stat.h @@ -22,13 +22,14 @@ * pv_kick_wake - # of vCPU kicks used for computing pv_latency_wake * pv_latency_kick - average latency (ns) of vCPU kick operation * pv_latency_wake - average latency (ns) from vCPU kick to wakeup - * pv_lock_slowpath - # of locking operations via the slowpath * pv_lock_stealing - # of lock stealing operations * pv_spurious_wakeup - # of spurious wakeups in non-head vCPUs * pv_wait_again - # of wait's after a queue head vCPU kick * pv_wait_early - # of early vCPU wait's * pv_wait_head - # of vCPU wait's at the queue head * 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 * * Writing to the "reset_counters" file will reset all the above counter * values. @@ -46,13 +47,14 @@ enum qlock_stats { qstat_pv_kick_wake, qstat_pv_latency_kick, qstat_pv_latency_wake, - qstat_pv_lock_slowpath, qstat_pv_lock_stealing, qstat_pv_spurious_wakeup, qstat_pv_wait_again, qstat_pv_wait_early, qstat_pv_wait_head, qstat_pv_wait_node, + qstat_lock_pending, + qstat_lock_slowpath, qstat_num, /* Total number of statistical counters */ qstat_reset_cnts = qstat_num, }; @@ -73,12 +75,13 @@ static const char * const qstat_names[qstat_num + 1] = { [qstat_pv_spurious_wakeup] = "pv_spurious_wakeup", [qstat_pv_latency_kick] = "pv_latency_kick", [qstat_pv_latency_wake] = "pv_latency_wake", - [qstat_pv_lock_slowpath] = "pv_lock_slowpath", [qstat_pv_lock_stealing] = "pv_lock_stealing", [qstat_pv_wait_again] = "pv_wait_again", [qstat_pv_wait_early] = "pv_wait_early", [qstat_pv_wait_head] = "pv_wait_head", [qstat_pv_wait_node] = "pv_wait_node", + [qstat_lock_pending] = "lock_pending", + [qstat_lock_slowpath] = "lock_slowpath", [qstat_reset_cnts] = "reset_counters", };