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Commit c0a54341 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf evsel: Introduce event fallback method 

The only fallback right now is for HW cpu-cycles -> SW cpu-clock, that
was done in the same way in both 'top' and 'record'.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-58l1mgibh9oa9m0pd3fasxa5@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 594ac61a

tools/perf/builtin-record.c

+3 −20
Original line number Diff line number Diff line
@@ -224,6 +224,7 @@ static bool perf_evlist__equal(struct perf_evlist *evlist, 


static int perf_record__open(struct perf_record *rec)

{

	char msg[128];

	struct perf_evsel *pos;

	struct perf_evlist *evlist = rec->evlist;

	struct perf_session *session = rec->session;
@@ -249,27 +250,9 @@ static int perf_record__open(struct perf_record *rec) 
				goto out;

			}



			/*

			 * If it's cycles then fall back to hrtimer

			 * based cpu-clock-tick sw counter, which

			 * is always available even if no PMU support.

			 *

			 * PPC returns ENXIO until 2.6.37 (behavior changed

			 * with commit b0a873e).

			 */

			if ((err == ENOENT || err == ENXIO)

					&& attr->type == PERF_TYPE_HARDWARE

					&& attr->config == PERF_COUNT_HW_CPU_CYCLES) {



			if (perf_evsel__fallback(pos, err, msg, sizeof(msg))) {

				if (verbose)

					ui__warning("The cycles event is not supported, "

						    "trying to fall back to cpu-clock-ticks\n");

				attr->type = PERF_TYPE_SOFTWARE;

				attr->config = PERF_COUNT_SW_CPU_CLOCK;

				if (pos->name) {

					free(pos->name);

					pos->name = NULL;

				}

					ui__warning("%s\n", msg);

				goto try_again;

			}

tools/perf/builtin-top.c

+3 −17
Original line number Diff line number Diff line
@@ -892,6 +892,7 @@ static void perf_top__mmap_read(struct perf_top *top) 


static void perf_top__start_counters(struct perf_top *top)

{

	char msg[128];

	struct perf_evsel *counter;

	struct perf_evlist *evlist = top->evlist;

	struct perf_record_opts *opts = &top->record_opts;
@@ -909,25 +910,10 @@ static void perf_top__start_counters(struct perf_top *top) 
				ui__error_paranoid();

				goto out_err;

			}

			/*

			 * If it's cycles then fall back to hrtimer

			 * based cpu-clock-tick sw counter, which

			 * is always available even if no PMU support:

			 */

			if ((err == ENOENT || err == ENXIO) &&

			    (attr->type == PERF_TYPE_HARDWARE) &&

			    (attr->config == PERF_COUNT_HW_CPU_CYCLES)) {



			if (perf_evsel__fallback(counter, err, msg, sizeof(msg))) {

				if (verbose)

					ui__warning("Cycles event not supported,\n"

						    "trying to fall back to cpu-clock-ticks\n");



				attr->type = PERF_TYPE_SOFTWARE;

				attr->config = PERF_COUNT_SW_CPU_CLOCK;

				if (counter->name) {

					free(counter->name);

					counter->name = NULL;

				}

					ui__warning("%s\n", msg);

				goto try_again;

			}

tools/perf/util/evsel.c

+28 −0
Original line number Diff line number Diff line
@@ -1378,3 +1378,31 @@ int perf_evsel__fprintf(struct perf_evsel *evsel, 
	fputc('\n', fp);

	return ++printed;

}



bool perf_evsel__fallback(struct perf_evsel *evsel, int err,

			  char *msg, size_t msgsize)

{

	if ((err == ENOENT || err == ENXIO) &&

	    evsel->attr.type   == PERF_TYPE_HARDWARE &&

	    evsel->attr.config == PERF_COUNT_HW_CPU_CYCLES) {

		/*

		 * If it's cycles then fall back to hrtimer based

		 * cpu-clock-tick sw counter, which is always available even if

		 * no PMU support.

		 *

		 * PPC returns ENXIO until 2.6.37 (behavior changed with commit

		 * b0a873e).

		 */

		scnprintf(msg, msgsize, "%s",

"The cycles event is not supported, trying to fall back to cpu-clock-ticks");



		evsel->attr.type   = PERF_TYPE_SOFTWARE;

		evsel->attr.config = PERF_COUNT_SW_CPU_CLOCK;



		free(evsel->name);

		evsel->name = NULL;

		return true;

	}



	return false;

}

tools/perf/util/evsel.h

+3 −0
Original line number Diff line number Diff line
@@ -251,4 +251,7 @@ struct perf_attr_details { 


int perf_evsel__fprintf(struct perf_evsel *evsel,

			struct perf_attr_details *details, FILE *fp);



bool perf_evsel__fallback(struct perf_evsel *evsel, int err,

			  char *msg, size_t msgsize);

#endif /* __PERF_EVSEL_H */