From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755308AbbIMLNM (ORCPT ); Sun, 13 Sep 2015 07:13:12 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44014 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752029AbbIMLNK (ORCPT ); Sun, 13 Sep 2015 07:13:10 -0400 Date: Sun, 13 Sep 2015 04:12:23 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: acme@redhat.com, vincent.weaver@maine.edu, acme@kernel.org, peterz@infradead.org, hpa@zytor.com, linux-kernel@vger.kernel.org, mpe@ellerman.id.au, sukadev@linux.vnet.ibm.com, torvalds@linux-foundation.org, jolsa@redhat.com, eranian@google.com, mingo@kernel.org, tglx@linutronix.de Reply-To: hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, vincent.weaver@maine.edu, acme@kernel.org, acme@redhat.com, tglx@linutronix.de, mingo@kernel.org, torvalds@linux-foundation.org, eranian@google.com, jolsa@redhat.com, mpe@ellerman.id.au, sukadev@linux.vnet.ibm.com In-Reply-To: <1441336073-22750-7-git-send-email-sukadev@linux.vnet.ibm.com> References: <1441336073-22750-7-git-send-email-sukadev@linux.vnet.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf/core: Invert perf_read_group() loops Git-Commit-ID: fa8c269353d560b7c28119ad7617029f92e40b15 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: fa8c269353d560b7c28119ad7617029f92e40b15 Gitweb: http://git.kernel.org/tip/fa8c269353d560b7c28119ad7617029f92e40b15 Author: Peter Zijlstra AuthorDate: Thu, 3 Sep 2015 20:07:49 -0700 Committer: Ingo Molnar CommitDate: Sun, 13 Sep 2015 11:27:27 +0200 perf/core: Invert perf_read_group() loops In order to enable the use of perf_event_read(.group = true), we need to invert the sibling-child loop nesting of perf_read_group(). Currently we iterate the child list for each sibling, this precludes using group reads. Flip things around so we iterate each group for each child. Signed-off-by: Peter Zijlstra (Intel) [ Made the patch compile and things. ] Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Michael Ellerman Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: http://lkml.kernel.org/r/1441336073-22750-7-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 85 +++++++++++++++++++++++++++++++++------------------- 1 file changed, 55 insertions(+), 30 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 4d89866..dd2a0b8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3862,50 +3862,75 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) } EXPORT_SYMBOL_GPL(perf_event_read_value); -static int perf_read_group(struct perf_event *event, - u64 read_format, char __user *buf) +static void __perf_read_group_add(struct perf_event *leader, + u64 read_format, u64 *values) { - struct perf_event *leader = event->group_leader, *sub; - struct perf_event_context *ctx = leader->ctx; - int n = 0, size = 0, ret; - u64 count, enabled, running; - u64 values[5]; + struct perf_event *sub; + int n = 1; /* skip @nr */ - lockdep_assert_held(&ctx->mutex); + perf_event_read(leader, true); + + /* + * Since we co-schedule groups, {enabled,running} times of siblings + * will be identical to those of the leader, so we only publish one + * set. + */ + if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { + values[n++] += leader->total_time_enabled + + atomic64_read(&leader->child_total_time_enabled); + } - count = perf_event_read_value(leader, &enabled, &running); + if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { + values[n++] += leader->total_time_running + + atomic64_read(&leader->child_total_time_running); + } - values[n++] = 1 + leader->nr_siblings; - if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) - values[n++] = enabled; - if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) - values[n++] = running; - values[n++] = count; + /* + * Write {count,id} tuples for every sibling. + */ + values[n++] += perf_event_count(leader); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); - size = n * sizeof(u64); + list_for_each_entry(sub, &leader->sibling_list, group_entry) { + values[n++] += perf_event_count(sub); + if (read_format & PERF_FORMAT_ID) + values[n++] = primary_event_id(sub); + } +} - if (copy_to_user(buf, values, size)) - return -EFAULT; +static int perf_read_group(struct perf_event *event, + u64 read_format, char __user *buf) +{ + struct perf_event *leader = event->group_leader, *child; + struct perf_event_context *ctx = leader->ctx; + int ret = event->read_size; + u64 *values; - ret = size; + lockdep_assert_held(&ctx->mutex); - list_for_each_entry(sub, &leader->sibling_list, group_entry) { - n = 0; + values = kzalloc(event->read_size, GFP_KERNEL); + if (!values) + return -ENOMEM; - values[n++] = perf_event_read_value(sub, &enabled, &running); - if (read_format & PERF_FORMAT_ID) - values[n++] = primary_event_id(sub); + values[0] = 1 + leader->nr_siblings; + + /* + * By locking the child_mutex of the leader we effectively + * lock the child list of all siblings.. XXX explain how. + */ + mutex_lock(&leader->child_mutex); - size = n * sizeof(u64); + __perf_read_group_add(leader, read_format, values); + list_for_each_entry(child, &leader->child_list, child_list) + __perf_read_group_add(child, read_format, values); - if (copy_to_user(buf + ret, values, size)) { - return -EFAULT; - } + mutex_unlock(&leader->child_mutex); - ret += size; - } + if (copy_to_user(buf, values, event->read_size)) + ret = -EFAULT; + + kfree(values); return ret; }