Re: [PATCH] perf bench: add benchmark for evlist open/close operations

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>, Jiri Olsa <jolsa@redhat.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH] perf bench: add benchmark for evlist open/close operations
Date: Mon, 9 Aug 2021 17:28:12 -0300	[thread overview]
Message-ID: <YRGP3DR8f6ZEvn/P@kernel.org> (raw)
In-Reply-To: <YRGOwx3xlPRxNAXM@kernel.org>

Em Mon, Aug 09, 2021 at 05:23:31PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Aug 09, 2021 at 10:11:02PM +0200, Riccardo Mancini escreveu:
> > +static struct evlist *bench__create_evlist(char *evstr)
> > +{
> > +	struct evlist *evlist;
> > +	struct parse_events_error err;
> > +	int ret;

> > +	evlist = evlist__new();
> > +	if (!evlist) {
> > +		pr_err("Not enough memory to create evlist\n");
> > +		return NULL;
> > +	}

> > +	bzero(&err, sizeof(err));

> man bzero
> 
>        The bzero() function is deprecated (marked as LEGACY in POSIX.1-2001); use memset(3) in new programs.  POSIX.1-2008 removes the specification of bzero().  The bzero() function first appeared in 4.3BSD.

> I'm replacing it with a memset().

This one is also equivalent:

tools/perf/tests/pmu-events.c:	struct parse_events_error error = { .idx = 0, };

https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html

That text is a bit roundabout, as it says that the members that are not
explicitely initialized will be initialized as variables with static
storage duration, i.e. zeroed.

- Arnaldo