[PATCH v2] perf sched timehist: Improve error message when analyzing wrong file

[PATCH v2] perf sched timehist: Improve error message when analyzing wrong file

[David Ahern]

Arnaldo reported an unhelpful error message when running perf sched
timehist on a file that did not contain sched tracepoints:

    [root@jouet ~]# perf sched timehist
    No trace sample to read. Did you call 'perf record -R'?

    [root@jouet ~]# perf evlist -v
    cycles:ppp: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1

Change the has_traces check to look for the sched_switch event. Analysis
for perf sched timehist requires at least this event.

Now when analyzing a file without sched tracepoints you get:

    root@f21-vbox:/tmp$ perf sched timehist
    No sched_switch events found. Have you run 'perf sched record'?

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 tools/perf/builtin-sched.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 870d94cd20ba..84c39f177bef 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2629,8 +2629,12 @@ static int perf_sched__timehist(struct perf_sched *sched)
 	if (perf_session__set_tracepoints_handlers(session, handlers))
 		goto out;
 
-	if (!perf_session__has_traces(session, "record -R"))
+	/* sched_switch event at a minimum needs to exist */
+	if (!perf_evlist__find_tracepoint_by_name(session->evlist,
+						  "sched:sched_switch")) {
+		pr_err("No sched_switch events found. Have you run 'perf sched record'?\n");
 		goto out;
+	}
 
 	if (sched->show_migrations &&
 	    perf_session__set_tracepoints_handlers(session, migrate_handlers))
-- 
2.7.4 (Apple Git-66)

Re: [PATCH v2] perf sched timehist: Improve error message when analyzing wrong file

[Namhyung Kim]

On 11/30/16, David Ahern <dsahern@gmail.com> wrote:
> Arnaldo reported an unhelpful error message when running perf sched
> timehist on a file that did not contain sched tracepoints:
>
>     [root@jouet ~]# perf sched timehist
>     No trace sample to read. Did you call 'perf record -R'?
>
>     [root@jouet ~]# perf evlist -v
>     cycles:ppp: size: 112, { sample_period, sample_freq }: 4000,
> sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD, disabled: 1, inherit: 1,
> mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1,
> exclude_guest: 1, mmap2: 1, comm_exec: 1
>
> Change the has_traces check to look for the sched_switch event. Analysis
> for perf sched timehist requires at least this event.
>
> Now when analyzing a file without sched tracepoints you get:
>
>     root@f21-vbox:/tmp$ perf sched timehist
>     No sched_switch events found. Have you run 'perf sched record'?
>
> Signed-off-by: David Ahern <dsahern@gmail.com>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
>  tools/perf/builtin-sched.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 870d94cd20ba..84c39f177bef 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -2629,8 +2629,12 @@ static int perf_sched__timehist(struct perf_sched
> *sched)
>  	if (perf_session__set_tracepoints_handlers(session, handlers))
>  		goto out;
>
> -	if (!perf_session__has_traces(session, "record -R"))
> +	/* sched_switch event at a minimum needs to exist */
> +	if (!perf_evlist__find_tracepoint_by_name(session->evlist,
> +						  "sched:sched_switch")) {
> +		pr_err("No sched_switch events found. Have you run 'perf sched
> record'?\n");
>  		goto out;
> +	}
>
>  	if (sched->show_migrations &&
>  	    perf_session__set_tracepoints_handlers(session, migrate_handlers))
> --
> 2.7.4 (Apple Git-66)
>
>


-- 
Thanks,
Namhyung Kim

Re: [PATCH v2] perf sched timehist: Improve error message when analyzing wrong file

[David Ahern]

On 11/29/16 9:31 PM, Namhyung Kim wrote:
> On 11/30/16, David Ahern <dsahern@gmail.com> wrote:
>> Arnaldo reported an unhelpful error message when running perf sched
>> timehist on a file that did not contain sched tracepoints:
>>
>>     [root@jouet ~]# perf sched timehist
>>     No trace sample to read. Did you call 'perf record -R'?
>>
>>     [root@jouet ~]# perf evlist -v
>>     cycles:ppp: size: 112, { sample_period, sample_freq }: 4000,
>> sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD, disabled: 1, inherit: 1,
>> mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1,
>> exclude_guest: 1, mmap2: 1, comm_exec: 1
>>
>> Change the has_traces check to look for the sched_switch event. Analysis
>> for perf sched timehist requires at least this event.
>>
>> Now when analyzing a file without sched tracepoints you get:
>>
>>     root@f21-vbox:/tmp$ perf sched timehist
>>     No sched_switch events found. Have you run 'perf sched record'?
>>
>> Signed-off-by: David Ahern <dsahern@gmail.com>
> 
> Acked-by: Namhyung Kim <namhyung@kernel.org>
> 
> Thanks,
> Namhyung
> 

Arnaldo: I think this one has been overlooked

Re: [PATCH v2] perf sched timehist: Improve error message when analyzing wrong file

[Arnaldo Carvalho de Melo]

Em Mon, Dec 05, 2016 at 03:41:54PM -0800, David Ahern escreveu:
> On 11/29/16 9:31 PM, Namhyung Kim wrote:
> > On 11/30/16, David Ahern <dsahern@gmail.com> wrote:
> >> Arnaldo reported an unhelpful error message when running perf sched
> >> timehist on a file that did not contain sched tracepoints:
> >>     root@f21-vbox:/tmp$ perf sched timehist
> >>     No sched_switch events found. Have you run 'perf sched record'?
> >>
> >> Signed-off-by: David Ahern <dsahern@gmail.com>
> > 
> > Acked-by: Namhyung Kim <namhyung@kernel.org>
> > 
> > Thanks,
> > Namhyung
> > 
> 
> Arnaldo: I think this one has been overlooked

Ooops, Reported-and-Forgot-by: Arnaldo, ok, tested, applied, thanks!

- Arnaldo

[tip:perf/core] perf sched timehist: Improve error message when analyzing wrong file

[tip-bot for David Ahern]

Commit-ID:  f45bf8d3939d8f32f06ec12e56d2b8651c5437b4
Gitweb:     http://git.kernel.org/tip/f45bf8d3939d8f32f06ec12e56d2b8651c5437b4
Author:     David Ahern <dsahern@gmail.com>
AuthorDate: Tue, 29 Nov 2016 13:39:48 -0700
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 7 Dec 2016 12:00:32 -0300

perf sched timehist: Improve error message when analyzing wrong file

Arnaldo reported an unhelpful error message when running perf sched
timehist on a file that did not contain sched tracepoints:

    [root@jouet ~]# perf sched timehist
    No trace sample to read. Did you call 'perf record -R'?

    [root@jouet ~]# perf evlist -v
    cycles:ppp: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1

Change the has_traces check to look for the sched_switch event. Analysis
for perf sched timehist requires at least this event.

Now when analyzing a file without sched tracepoints you get:

    root@f21-vbox:/tmp$ perf sched timehist
    No sched_switch events found. Have you run 'perf sched record'?

Signed-off-by: David Ahern <dsahern@gmail.com>
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1480451988-43673-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-sched.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 870d94c..84c39f1 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2629,8 +2629,12 @@ static int perf_sched__timehist(struct perf_sched *sched)
 	if (perf_session__set_tracepoints_handlers(session, handlers))
 		goto out;
 
-	if (!perf_session__has_traces(session, "record -R"))
+	/* sched_switch event at a minimum needs to exist */
+	if (!perf_evlist__find_tracepoint_by_name(session->evlist,
+						  "sched:sched_switch")) {
+		pr_err("No sched_switch events found. Have you run 'perf sched record'?\n");
 		goto out;
+	}
 
 	if (sched->show_migrations &&
 	    perf_session__set_tracepoints_handlers(session, migrate_handlers))