Re: [PATCH 5/7] perf session: don't rely on evlist in pipe mode

[David Carrillo-Cisneros]

Only the second one is needed. file is already checked for the first one.

On Tue, Apr 11, 2017 at 11:44 AM, Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
> Em Tue, Apr 11, 2017 at 03:40:50PM -0300, Arnaldo Carvalho de Melo escreveu:
>> Em Tue, Apr 11, 2017 at 03:40:14PM -0300, Arnaldo Carvalho de Melo escreveu:
>> > Em Mon, Apr 10, 2017 at 01:14:30PM -0700, David Carrillo-Cisneros escreveu:
>> > > Session sets a number parameters that rely on evlist. These parameters
>> > > are not used in pipe-mode and should not be set, since evlist is
>> > > unavailable. Fix that.
>> >
>> > Ditching this one as well, until further investigation, well, file must
>> > be null in this case...
>
> This should be enough, right?
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index db554b7461b8..37cf4e6abf9f 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -144,7 +144,7 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
>                          * set session attributes that are present in perf.data
>                          * but not in pipe-mode.
>                          */
> -                       if (!file->is_pipe) {
> +                       if (!file || !file->is_pipe) {
>                                 perf_session__set_id_hdr_size(session);
>                                 perf_session__set_comm_exec(session);
>                         }
> @@ -166,7 +166,7 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
>          * In pipe-mode, evlist is empty until PERF_RECORD_HEADER_ATTR is
>          * processed, so perf_evlist__sample_id_all is not meaningful here.
>          */
> -       if (!file->is_pipe && tool && tool->ordering_requires_timestamps &&
> +       if ((!file || !file->is_pipe) && tool && tool->ordering_requires_timestamps &&
>             tool->ordered_events && !perf_evlist__sample_id_all(session->evlist)) {
>                 dump_printf("WARNING: No sample_id_all support, falling back to unordered processing\n");
>                 tool->ordered_events = false;
>
>> Ah, this is the problem:
>>
>> [root@jouet ~]# perf top
>> perf: Segmentation fault
>> -------- backtrace --------
>> perf[0x57eddb]
>> /lib64/libc.so.6(+0x35990)[0x7fb435d06990]
>> perf(perf_session__new+0xb7)[0x4eb547]
>> perf(cmd_top+0xde9)[0x44ce89]
>> perf[0x49953f]
>> perf[0x499831]
>> perf(main+0x252)[0x428dd2]
>> /lib64/libc.so.6(__libc_start_main+0xf1)[0x7fb435cf1401]
>> perf(_start+0x2a)[0x4292da]
>> [0x0]
>> [root@jouet ~]#
>>
>> > [acme@jouet linux]$ git bisect bad
>> > 5d71c27204d51492abe9fc69064fd36a0bda410b is the first bad commit
>> > commit 5d71c27204d51492abe9fc69064fd36a0bda410b
>> > Author: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
>> > Date:   Mon Apr 10 13:14:30 2017 -0700
>> >
>> >     perf session: Don't rely on evlist in pipe mode
>> >
>> >     Session sets a number parameters that rely on evlist. These parameters
>> >     are not used in pipe-mode and should not be set, since evlist is
>> >     unavailable. Fix that.
>> >
>> >     Signed-off-by: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
>> >     Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
>> >     Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
>> >     Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>> >     Cc: He Kuang <hekuang@xxxxxxxxxx>
>> >     Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
>> >     Cc: Paul Turner <pjt@xxxxxxxxxx>
>> >     Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>> >     Cc: Simon Que <sque@xxxxxxxxxxxx>
>> >     Cc: Stephane Eranian <eranian@xxxxxxxxxx>
>> >     Cc: Wang Nan <wangnan0@xxxxxxxxxx>
>> >     Link: http://lkml.kernel.org/r/20170410201432.24807-6-davidcc@xxxxxxxxxx
>> >     Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>> >
>> > :040000 040000 7df28fe9d7c9d962b78c0532f4961caea2737b59 34e4fed0042b1401c1a1a247d8ae40df17f9d272 M  tools
>> > [acme@jouet linux]$
>> >
>> > > Signed-off-by: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
>> > > ---
>> > >  tools/perf/util/session.c | 16 +++++++++++++---
>> > >  1 file changed, 13 insertions(+), 3 deletions(-)
>> > >
>> > > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
>> > > index a25302bc55a8..db554b7461b8 100644
>> > > --- a/tools/perf/util/session.c
>> > > +++ b/tools/perf/util/session.c
>> > > @@ -140,8 +140,14 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
>> > >                   if (perf_session__open(session) < 0)
>> > >                           goto out_close;
>> > >
>> > > -                 perf_session__set_id_hdr_size(session);
>> > > -                 perf_session__set_comm_exec(session);
>> > > +                 /*
>> > > +                  * set session attributes that are present in perf.data
>> > > +                  * but not in pipe-mode.
>> > > +                  */
>> > > +                 if (!file->is_pipe) {
>> > > +                         perf_session__set_id_hdr_size(session);
>> > > +                         perf_session__set_comm_exec(session);
>> > > +                 }
>> > >           }
>> > >   } else  {
>> > >           session->machines.host.env = &perf_env;
>> > > @@ -156,7 +162,11 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
>> > >                   pr_warning("Cannot read kernel map\n");
>> > >   }
>> > >
>> > > - if (tool && tool->ordering_requires_timestamps &&
>> > > + /*
>> > > +  * In pipe-mode, evlist is empty until PERF_RECORD_HEADER_ATTR is
>> > > +  * processed, so perf_evlist__sample_id_all is not meaningful here.
>> > > +  */
>> > > + if (!file->is_pipe && tool && tool->ordering_requires_timestamps &&
>> > >       tool->ordered_events && !perf_evlist__sample_id_all(session->evlist)) {
>> > >           dump_printf("WARNING: No sample_id_all support, falling back to unordered processing\n");
>> > >           tool->ordered_events = false;
>> > > --
>> > > 2.12.2.715.g7642488e1d-goog