From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: [PATCH v3 2/4] locking/qspinlock_stat: Track the no MCS node available case Date: Tue, 29 Jan 2019 22:53:46 +0100 Message-ID: <1548798828-16156-3-git-send-email-longman@redhat.com> References: <1548798828-16156-1-git-send-email-longman@redhat.com> Return-path: In-Reply-To: <1548798828-16156-1-git-send-email-longman@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra , Ingo Molnar , Will Deacon , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, Zhenzhong Duan , James Morse , SRINIVAS , Waiman Long List-Id: linux-arch.vger.kernel.org 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 --- 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 0875053..21ee51b 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -422,6 +422,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * 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 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) /* * 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 42d3d8d..365ce6d 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 percpu node + * lock_use_node3 - # of locking operations that use 3rd percpu node + * lock_use_node4 - # of locking operations that use 4th percpu node + * lock_no_node - # of locking operations without using percpu 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 @@ enum qlock_stats { [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", }; -- 1.8.3.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:48012 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729593AbfA2VyG (ORCPT ); Tue, 29 Jan 2019 16:54:06 -0500 From: Waiman Long Subject: [PATCH v3 2/4] locking/qspinlock_stat: Track the no MCS node available case Date: Tue, 29 Jan 2019 22:53:46 +0100 Message-ID: <1548798828-16156-3-git-send-email-longman@redhat.com> In-Reply-To: <1548798828-16156-1-git-send-email-longman@redhat.com> References: <1548798828-16156-1-git-send-email-longman@redhat.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra , Ingo Molnar , Will Deacon , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, Zhenzhong Duan , James Morse , SRINIVAS , Waiman Long Message-ID: <20190129215346.E4tNrcz5ULQ38XclCOCcSIr4FBanWjayphc4Tl_nnZM@z> 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 --- 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 0875053..21ee51b 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -422,6 +422,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * 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 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) /* * 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 42d3d8d..365ce6d 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 percpu node + * lock_use_node3 - # of locking operations that use 3rd percpu node + * lock_use_node4 - # of locking operations that use 4th percpu node + * lock_no_node - # of locking operations without using percpu 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 @@ enum qlock_stats { [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", }; -- 1.8.3.1