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Message-ID: <20181023063452.GB20075@krava>
Date: Tue, 23 Oct 2018 08:34:52 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: David Miller <davem@...emloft.net>
Cc: dzickus@...hat.com, acme@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: perf overlapping maps...
On Mon, Oct 22, 2018 at 10:58:42AM -0700, David Miller wrote:
> From: Jiri Olsa <jolsa@...hat.com>
> Date: Mon, 22 Oct 2018 18:16:13 +0200
>
> > I think the fix might actualy speed things up,
> > but yes, there could be other report regressions
>
> I was about to say the same thing, it could actually speed things up.
> In the best case, less work is done (clone avoided, and overlapping
> maps don't have to be handled). In the worst case, nothing changes.
>
> Here is what I've been using, to give you an idea. There may be some
> file offset fuzz in these patches.
I'm not sure about using the misc field bit defined/used by userland,
in case there's some new one comming in future for fork event..
but the only other way I can think of now is adding new 'user' event
for that, but that ended up as a bigger change (attached)
I think if we make some 'big enough' comment about the bit usage,
your change is better.. will you post or should I?
thanks,
jirka
---
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index bc646185f8d9..06e28cef5579 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -60,6 +60,7 @@ static const char *perf_event__names[] = {
[PERF_RECORD_EVENT_UPDATE] = "EVENT_UPDATE",
[PERF_RECORD_TIME_CONV] = "TIME_CONV",
[PERF_RECORD_HEADER_FEATURE] = "FEATURE",
+ [PERF_RECORD_FORK_USER] = "FORK_USER",
};
static const char *perf_ns__names[] = {
@@ -307,7 +308,7 @@ static int perf_event__synthesize_fork(struct perf_tool *tool,
}
event->fork.pid = tgid;
event->fork.tid = pid;
- event->fork.header.type = PERF_RECORD_FORK;
+ event->fork.header.type = PERF_RECORD_FORK_USER;
event->fork.header.size = (sizeof(event->fork) + machine->id_hdr_size);
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index bfa60bcafbde..e7252ae61529 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -249,6 +249,7 @@ enum perf_user_event_type { /* above any possible kernel type */
PERF_RECORD_EVENT_UPDATE = 78,
PERF_RECORD_TIME_CONV = 79,
PERF_RECORD_HEADER_FEATURE = 80,
+ PERF_RECORD_FORK_USER = 81,
PERF_RECORD_HEADER_MAX
};
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 111ae858cbcb..b7d8aec18707 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1702,6 +1702,7 @@ void machine__remove_thread(struct machine *machine, struct thread *th)
int machine__process_fork_event(struct machine *machine, union perf_event *event,
struct perf_sample *sample)
{
+ bool user = event->header.type == PERF_RECORD_FORK_USER;
struct thread *thread = machine__find_thread(machine,
event->fork.pid,
event->fork.tid);
@@ -1738,7 +1739,7 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event
event->fork.tid);
if (thread == NULL || parent == NULL ||
- thread__fork(thread, parent, sample->time) < 0) {
+ thread__fork(thread, parent, sample->time, user) < 0) {
dump_printf("problem processing PERF_RECORD_FORK, skipping event.\n");
err = -1;
}
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index df5e12b22905..a219dd119d95 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -801,6 +801,7 @@ static perf_event__swap_op perf_event__swap_ops[] = {
[PERF_RECORD_STAT_ROUND] = perf_event__stat_round_swap,
[PERF_RECORD_EVENT_UPDATE] = perf_event__event_update_swap,
[PERF_RECORD_TIME_CONV] = perf_event__all64_swap,
+ [PERF_RECORD_FORK_USER] = perf_event__task_swap,
[PERF_RECORD_HEADER_MAX] = NULL,
};
@@ -1269,6 +1270,7 @@ static int machines__deliver_event(struct machines *machines,
case PERF_RECORD_NAMESPACES:
return tool->namespaces(tool, event, sample, machine);
case PERF_RECORD_FORK:
+ case PERF_RECORD_FORK_USER:
return tool->fork(tool, event, sample, machine);
case PERF_RECORD_EXIT:
return tool->exit(tool, event, sample, machine);
@@ -1398,6 +1400,12 @@ static s64 perf_session__process_user_event(struct perf_session *session,
}
}
+static bool process_user(union perf_event *event)
+{
+ return event->header.type >= PERF_RECORD_USER_TYPE_START &&
+ event->header.type != PERF_RECORD_FORK_USER;
+}
+
int perf_session__deliver_synth_event(struct perf_session *session,
union perf_event *event,
struct perf_sample *sample)
@@ -1407,7 +1415,7 @@ int perf_session__deliver_synth_event(struct perf_session *session,
events_stats__inc(&evlist->stats, event->header.type);
- if (event->header.type >= PERF_RECORD_USER_TYPE_START)
+ if (process_user(event))
return perf_session__process_user_event(session, event, 0);
return machines__deliver_event(&session->machines, evlist, event, sample, tool, 0);
@@ -1492,7 +1500,7 @@ static s64 perf_session__process_event(struct perf_session *session,
events_stats__inc(&evlist->stats, event->header.type);
- if (event->header.type >= PERF_RECORD_USER_TYPE_START)
+ if (process_user(event))
return perf_session__process_user_event(session, event, file_offset);
if (tool->ordered_events) {
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 2048d393ece6..2782d2626f09 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -332,10 +332,6 @@ static int thread__prepare_access(struct thread *thread)
static int thread__clone_map_groups(struct thread *thread,
struct thread *parent)
{
- /* This is new thread, we share map groups for process. */
- if (thread->pid_ == parent->pid_)
- return thread__prepare_access(thread);
-
if (thread->mg == parent->mg) {
pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
thread->pid_, thread->tid, parent->pid_, parent->tid);
@@ -343,13 +339,11 @@ static int thread__clone_map_groups(struct thread *thread,
}
/* But this one is new process, copy maps. */
- if (map_groups__clone(thread, parent->mg) < 0)
- return -ENOMEM;
-
- return 0;
+ return map_groups__clone(thread, parent->mg);
}
-int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
+int thread__fork(struct thread *thread, struct thread *parent,
+ u64 timestamp, bool user)
{
if (parent->comm_set) {
const char *comm = thread__comm_str(parent);
@@ -362,6 +356,15 @@ int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
}
thread->ppid = parent->tid;
+
+ /* This is new thread, we share map groups for process. */
+ if (thread->pid_ == parent->pid_)
+ return thread__prepare_access(thread);
+
+ /* Do not clone maps for user space fork event. */
+ if (user)
+ return 0;
+
return thread__clone_map_groups(thread, parent);
}
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 07606aa6998d..827727300100 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -87,7 +87,8 @@ struct comm *thread__comm(const struct thread *thread);
struct comm *thread__exec_comm(const struct thread *thread);
const char *thread__comm_str(const struct thread *thread);
int thread__insert_map(struct thread *thread, struct map *map);
-int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp);
+int thread__fork(struct thread *thread, struct thread *parent,
+ u64 timestamp, bool user);
size_t thread__fprintf(struct thread *thread, FILE *fp);
struct thread *thread__main_thread(struct machine *machine, struct thread *thread);
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