From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org
Subject: [[PATCH v6 06/10] perf: Invert perf_read_group() loops
Date: Thu, 3 Sep 2015 20:07:49 -0700 [thread overview]
Message-ID: <1441336073-22750-7-git-send-email-sukadev@linux.vnet.ibm.com> (raw)
In-Reply-To: <1441336073-22750-1-git-send-email-sukadev@linux.vnet.ibm.com>
From: Peter Zijlstra <peterz@infradead.org>
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) <peterz@infradead.org>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
---
Changes to Peter's patch:
- Add GFP_KERNEL to kzalloc().
- Pass in address of counter to atomic_read().
- Return event->size rather than leader->size (perf_read_group())
- Keep chkpatch happy.
---
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 7bb9141..2c38c09 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;
}
--
1.7.9.5
next prev parent reply other threads:[~2015-09-04 3:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-04 3:07 [PATCH v6 0/10] perf: Implement group-read of events using txn interface Sukadev Bhattiprolu
2015-09-04 3:07 ` [[PATCH v6 01/10] sparc/perf: Remove unnecessary assignment Sukadev Bhattiprolu
2015-09-04 3:07 ` [[PATCH v6 02/10] perf: Add a flags parameter to pmu txn interfaces Sukadev Bhattiprolu
2015-09-04 10:07 ` Michael Ellerman
2015-09-04 3:07 ` [[PATCH v6 03/10] perf: Split perf_event_read() and perf_event_count() Sukadev Bhattiprolu
2015-09-04 3:07 ` [[PATCH v6 04/10] perf: Rename perf_event_read_{one, group}, perf_read_hw Sukadev Bhattiprolu
2015-09-04 3:07 ` [[PATCH v6 05/10] perf: Add group reads to perf_event_read() Sukadev Bhattiprolu
2015-09-04 3:07 ` Sukadev Bhattiprolu [this message]
2015-09-04 3:07 ` [[PATCH v6 07/10] perf: Add return value for perf_event_read() Sukadev Bhattiprolu
2015-09-04 3:07 ` [[PATCH v6 08/10] Define PERF_PMU_TXN_READ interface Sukadev Bhattiprolu
2015-09-04 3:07 ` [[PATCH v6 09/10] powerpc/perf/hv-24x7: Use PMU_TXN_READ interface Sukadev Bhattiprolu
2015-09-08 9:07 ` Michael Ellerman
2015-09-08 11:29 ` Peter Zijlstra
2015-09-09 2:15 ` Michael Ellerman
2015-09-09 21:12 ` Sukadev Bhattiprolu
2015-09-10 0:43 ` Michael Ellerman
2015-09-04 3:07 ` [[PATCH v6 10/10] perf: Drop PERF_EVENT_TXN Sukadev Bhattiprolu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1441336073-22750-7-git-send-email-sukadev@linux.vnet.ibm.com \
--to=sukadev@linux.vnet.ibm.com \
--cc=acme@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=peterz@infradead.org \
--cc=sparclinux@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).