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From:   Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Date:   Fri, 18 Oct 2019 15:16:31 -0300
To:     Jiri Olsa <jolsa@kernel.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Michael Petlan <mpetlan@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        Stephane Eranian <eranian@google.com>,
        Jin Yao <yao.jin@linux.intel.com>,
        Alexey Budankov <alexey.budankov@linux.intel.com>
Subject: Re: [PATCH 07/10] libperf: Add tests_mmap_cpus test
Message-ID: <20191018181631.GF1797@kernel.org>
References: <20191017105918.20873-1-jolsa@kernel.org>
 <20191017105918.20873-8-jolsa@kernel.org>
 <20191018181429.GE1797@kernel.org>
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Em Fri, Oct 18, 2019 at 03:14:29PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Oct 17, 2019 at 12:59:15PM +0200, Jiri Olsa escreveu:
> > Adding mmaping tests that generates prctl call on
> > every cpu validates it gets all the related events
> > in ring buffer.
> 
> So _here_ we need _GNU_SOURCE, for this specific test:

Added, to this test:

[acme@quaco perf]$ git diff
diff --git a/tools/perf/lib/tests/test-evlist.c b/tools/perf/lib/tests/test-evlist.c
index d8c52ebfa53a..741bc1bb4524 100644
--- a/tools/perf/lib/tests/test-evlist.c
+++ b/tools/perf/lib/tests/test-evlist.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <stdio.h>
+#define _GNU_SOURCE // needed for sched.h to get sched_[gs]etaffinity and CPU_(ZERO,SET)
 #include <sched.h>
+#include <stdio.h>
 #include <stdarg.h>
 #include <unistd.h>
 #include <stdlib.h>
[acme@quaco perf]$

We can go the big hammer way if this is more generally needed, but first
lets try to use it only when needed, ok?

- Arnaldo
 
>   LINK     test-evlist-a
> test-evlist.c: In function ‘test_mmap_cpus’:
> test-evlist.c:352:8: warning: implicit declaration of function ‘sched_getaffinity’ [-Wimplicit-function-declaration]
>   352 |  err = sched_getaffinity(0, sizeof(saved_mask), &saved_mask);
>       |        ^~~~~~~~~~~~~~~~~
> test-evlist.c:358:3: warning: implicit declaration of function ‘CPU_ZERO’ [-Wimplicit-function-declaration]
>   358 |   CPU_ZERO(&mask);
>       |   ^~~~~~~~
> test-evlist.c:359:3: warning: implicit declaration of function ‘CPU_SET’ [-Wimplicit-function-declaration]
>   359 |   CPU_SET(cpu, &mask);
>       |   ^~~~~~~
> test-evlist.c:361:9: warning: implicit declaration of function ‘sched_setaffinity’ [-Wimplicit-function-declaration]
>   361 |   err = sched_setaffinity(0, sizeof(mask), &mask);
>       |         ^~~~~~~~~~~~~~~~~
> /usr/bin/ld: /tmp/ccOhNrLC.o: in function `test_mmap_cpus':
> /home/acme/git/perf/tools/perf/lib/tests/test-evlist.c:358: undefined reference to `CPU_ZERO'
> /usr/bin/ld: /home/acme/git/perf/tools/perf/lib/tests/test-evlist.c:359: undefined reference to `CPU_SET'
> collect2: error: ld returned 1 exit status
> make[1]: *** [Makefile:22: test-evlist-a] Error 1
> make: *** [Makefile:143: tests] Error 2
> make: Leaving directory '/home/acme/git/perf/tools/perf/lib'
> [root@quaco perf]#
>  
> > Link: http://lkml.kernel.org/n/tip-9qdckblmgjm42ofd7haflso0@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  tools/perf/lib/tests/test-evlist.c | 97 ++++++++++++++++++++++++++++++
> >  1 file changed, 97 insertions(+)
> > 
> > diff --git a/tools/perf/lib/tests/test-evlist.c b/tools/perf/lib/tests/test-evlist.c
> > index 90a1869ba4b1..d8c52ebfa53a 100644
> > --- a/tools/perf/lib/tests/test-evlist.c
> > +++ b/tools/perf/lib/tests/test-evlist.c
> > @@ -1,5 +1,6 @@
> >  // SPDX-License-Identifier: GPL-2.0
> >  #include <stdio.h>
> > +#include <sched.h>
> >  #include <stdarg.h>
> >  #include <unistd.h>
> >  #include <stdlib.h>
> > @@ -299,6 +300,101 @@ static int test_mmap_thread(void)
> >  	return 0;
> >  }
> >  
> > +static int test_mmap_cpus(void)
> > +{
> > +	struct perf_evlist *evlist;
> > +	struct perf_evsel *evsel;
> > +	struct perf_mmap *map;
> > +	struct perf_cpu_map *cpus;
> > +	struct perf_event_attr attr = {
> > +		.type             = PERF_TYPE_TRACEPOINT,
> > +		.sample_period    = 1,
> > +		.wakeup_watermark = 1,
> > +		.disabled         = 1,
> > +	};
> > +	cpu_set_t saved_mask;
> > +	char path[PATH_MAX];
> > +	int id, err, cpu, tmp;
> > +	union perf_event *event;
> > +	int count = 0;
> > +
> > +	snprintf(path, PATH_MAX, "%s/kernel/debug/tracing/events/syscalls/sys_enter_prctl/id",
> > +		 sysfs__mountpoint());
> > +
> > +	if (filename__read_int(path, &id)) {
> > +		fprintf(stderr, "error: failed to get tracepoint id: %s\n", path);
> > +		return -1;
> > +	}
> > +
> > +	attr.config = id;
> > +
> > +	cpus = perf_cpu_map__new(NULL);
> > +	__T("failed to create cpus", cpus);
> > +
> > +	evlist = perf_evlist__new();
> > +	__T("failed to create evlist", evlist);
> > +
> > +	evsel = perf_evsel__new(&attr);
> > +	__T("failed to create evsel1", evsel);
> > +
> > +	perf_evlist__add(evlist, evsel);
> > +
> > +	perf_evlist__set_maps(evlist, cpus, NULL);
> > +
> > +	err = perf_evlist__open(evlist);
> > +	__T("failed to open evlist", err == 0);
> > +
> > +	err = perf_evlist__mmap(evlist, 4);
> > +	__T("failed to mmap evlist", err == 0);
> > +
> > +	perf_evlist__enable(evlist);
> > +
> > +	err = sched_getaffinity(0, sizeof(saved_mask), &saved_mask);
> > +	__T("sched_getaffinity failed", err == 0);
> > +
> > +	perf_cpu_map__for_each_cpu(cpu, tmp, cpus) {
> > +		cpu_set_t mask;
> > +
> > +		CPU_ZERO(&mask);
> > +		CPU_SET(cpu, &mask);
> > +
> > +		err = sched_setaffinity(0, sizeof(mask), &mask);
> > +		__T("sched_setaffinity failed", err == 0);
> > +
> > +		prctl(0, 0, 0, 0, 0);
> > +	}
> > +
> > +	err = sched_setaffinity(0, sizeof(saved_mask), &saved_mask);
> > +	__T("sched_setaffinity failed", err == 0);
> > +
> > +	perf_evlist__disable(evlist);
> > +
> > +	perf_evlist__for_each_mmap(evlist, map, false) {
> > +		if (perf_mmap__read_init(map) < 0)
> > +			continue;
> > +
> > +		while ((event = perf_mmap__read_event(map)) != NULL) {
> > +			count++;
> > +			perf_mmap__consume(map);
> > +		}
> > +
> > +		perf_mmap__read_done(map);
> > +	}
> > +
> > +	/* calls perf_evlist__munmap/perf_evlist__close */
> > +	perf_evlist__delete(evlist);
> > +
> > +	/*
> > +	 * The generated prctl events should match the
> > +	 * number of cpus or be bigger (we are system-wide).
> > +	 */
> > +	__T("failed count", count >= perf_cpu_map__nr(cpus));
> > +
> > +	perf_cpu_map__put(cpus);
> > +
> > +	return 0;
> > +}
> > +
> >  int main(int argc, char **argv)
> >  {
> >  	__T_START;
> > @@ -309,6 +405,7 @@ int main(int argc, char **argv)
> >  	test_stat_thread();
> >  	test_stat_thread_enable();
> >  	test_mmap_thread();
> > +	test_mmap_cpus();
> >  
> >  	__T_OK;
> >  	return 0;
> > -- 
> > 2.21.0
> 
> -- 
> 
> - Arnaldo

-- 

- Arnaldo