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: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 3 insertions, 17 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 74fca619fc4e..8d41d0b58956 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -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 @@ try_again:
                                 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;
                         }