linux-kernel - Re: [PATCH 1/1] perf tests task_analyzer: Check perf build options for libtraceevent support

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Message-ID: <3gmwq3qbe3lpcpvzwfaliyipoe7qrmqbbwd4fhsv7dj6q3kwpo@4g226sr4pm62>
Date:   Sat, 29 Jul 2023 13:09:37 +0530
From:   Aditya Gupta <adityag@...ux.ibm.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     jolsa@...nel.org, irogers@...gle.com, namhyung@...nel.org,
        linux-perf-users@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        maddy@...ux.ibm.com, atrajeev@...ux.vnet.ibm.com,
        kjain@...ux.ibm.com, disgoel@...ux.vnet.ibm.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] perf tests task_analyzer: Check perf build options
 for libtraceevent support

On Fri, Jul 28, 2023 at 11:54:11AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jul 25, 2023 at 11:46:49AM +0530, Aditya Gupta escreveu:
> > Currently we depend on output of 'perf record -e "sched:sched_switch"', to
> > check whether perf was built with libtraceevent support.
> > 
> > Instead, a more straightforward approach can be to check the build options,
> > using 'perf version --build-options', to check for libtraceevent support.
> > 
> > [...]
> > 
> > diff --git a/tools/perf/tests/shell/test_task_analyzer.sh b/tools/perf/tests/shell/test_task_analyzer.sh
> > index 0095abbe20ca..a28d784987b4 100755
> > --- a/tools/perf/tests/shell/test_task_analyzer.sh
> > +++ b/tools/perf/tests/shell/test_task_analyzer.sh
> > @@ -52,7 +52,7 @@ find_str_or_fail() {
> >  
> >  # check if perf is compiled with libtraceevent support
> >  skip_no_probe_record_support() {
> > -	perf record -e "sched:sched_switch" -a -- sleep 1 2>&1 | grep "libtraceevent is necessary for tracepoint support" && return 2
> > +	perf version --build-options | grep HAVE_LIBTRACEEVENT | grep -q OFF && return 2
> >  	return 0
> 
> I'll apply this, but please consider adding a:
> 
> 	perf build --has libtraceevent
> 
> subcommand to have that query made more compact and to avoid the two
> extra grep.

Okay. As you suggested in another reply, I found the code in builtin-version.c,
we can have a "perf build --has" option which can use the `IS_BUILTIN` macro
also used by "perf version --build-options". It can support all other feature
flags too.

You can implement it or I can work on a patch for that ?

It should require adding another 'struct option' to 'version_options', and
check for the flag in 'cmd_version()'. Will have to look how to get the string
passed after '--has'.

> 
> BTW, I'll change that to:
> 
> [acme@...co perf-tools-next]$ perf version --build-options | grep " on .* HAVE_LIBTRACEEVENT"
>          libtraceevent: [ on  ]  # HAVE_LIBTRACEEVENT
> [acme@...co perf-tools-next]$
> 
> replacing "on" with OFF, so that we have just one grep.

Okay.

Thanks,
- Aditya G