From patchwork Wed Apr 11 18:01:20 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 133156 Delivered-To: patch@linaro.org Received: by 10.46.84.29 with SMTP id i29csp895139ljb; Wed, 11 Apr 2018 11:01:25 -0700 (PDT) X-Google-Smtp-Source: AIpwx4+0PlZJuCEEFqAXnOu75ZZo0ou/RYe4n55I5XgH5El5jhzi0Zj2HYTD4/k045yBFETDZoMC X-Received: by 10.101.81.11 with SMTP id f11mr4206052pgq.150.1523469685271; Wed, 11 Apr 2018 11:01:25 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1523469685; cv=none; d=google.com; s=arc-20160816; b=msqwHIgwk2xlwXisrMFHc0TkNBOFYazcYrIfIkcgYBzf1LVybpVs+Q7nQNJZFXbIpy zeas/lPt9uDbMmd0COaJT94I2XMzMgBnXSWQadh0ayuiM+hVigWZYmFmb1Tc3ulwkH6U 8oT8yhABlQK0tb0AbB8zQj7ZkW+n4kI/dfi9ujgh4VqMK5zqW/zJlsLklIS0eyqMe89J mSPtwfcHxIkaiI+16XSxQNx+jl1S7sBMsDH/+aFvZjYnLNAXPa0AQH0mj8LufWE5ydlz tkzRnbElsjneNOWZjY4B3SbS9PXjLIJABd7HfGOlnkSBRPTUcyOqpsi7MMnuEqIa9/TZ Ovgg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=FynOxYFKxmol1hx5KiUFRtNAR98he4fUWuWi0/cUaj8=; b=aA3r66oNx2Z3NQCxjXlZ2fBL3qLbTgidKGwi/mgdLyJ1meGgOyvKxpMTkJ5QmL1PcT yyYh049rrByD9sE6inzylrt7mKxyHzmJdAm1kpo7PTQJg/HhPXfjkshQ9XkIkhDmnkUE Kloi3eDgYFGBjTdkY6RjllNO25QZLvXDdbqawgQ7ZqJf0RnjgnjdAs9fWAcjtTY6nton yHw32r3ZNL8Qqx1W1TIczosBeDACTMF0IPoDEkaPBRkswNUUGEeW9R16F+hd9KxU0+ts hOXCYhgMFCJZAEMsZ+RlAPRfb/0W6DVFPKtR8ocGMZgZJ3z5YvSg+0TfQ7GVnExeNEeP ovvQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id a85si1232213pfe.186.2018.04.11.11.01.24; Wed, 11 Apr 2018 11:01:25 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753833AbeDKSBS (ORCPT + 29 others); Wed, 11 Apr 2018 14:01:18 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:52128 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752735AbeDKSBI (ORCPT ); Wed, 11 Apr 2018 14:01:08 -0400 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 DE3E11713; Wed, 11 Apr 2018 11:01:07 -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 27F583F77D; Wed, 11 Apr 2018 11:01:07 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 204641AE55DA; Wed, 11 Apr 2018 19:01:22 +0100 (BST) From: Will Deacon To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, peterz@infradead.org, mingo@kernel.org, boqun.feng@gmail.com, paulmck@linux.vnet.ibm.com, longman@redhat.com Subject: [PATCH v2 13/13] locking/qspinlock: Add stat tracking for pending vs slowpath Date: Wed, 11 Apr 2018 19:01:20 +0100 Message-Id: <1523469680-17699-14-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1523469680-17699-1-git-send-email-will.deacon@arm.com> References: <1523469680-17699-1-git-send-email-will.deacon@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(-) -- 2.1.4 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 2711940429f5..970f47632b6f 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, @@ -433,7 +428,7 @@ 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", };