Commit-ID:  e6b33238e03466ca9b096368226f29fb4aec627a
Gitweb:     https://git.kernel.org/tip/e6b33238e03466ca9b096368226f29fb4aec627a
Author:     Kan Liang <kan.li...@intel.com>
AuthorDate: Thu, 18 Jan 2018 13:26:26 -0800
Committer:  Arnaldo Carvalho de Melo <a...@redhat.com>
CommitDate: Tue, 6 Feb 2018 10:11:50 -0300

perf top: Check per-event overwrite term

Per-event overwrite term is not forbidden in 'perf top', which can bring
problems. Because 'perf top' only support non-overwrite mode now.

Add new rules and check regarding to overwrite term for 'perf top'.
- All events either have same per-event term or don't have per-event
  mode setting. Otherwise, it will error out.
- Per-event overwrite term should be consistent as opts->overwrite.
  If not, updating the opts->overwrite according to per-event term.

Make it possible to support either non-overwrite or overwrite mode.
The overwrite mode is forbidden now, which will be removed when the
overwrite mode is supported later.

Signed-off-by: Kan Liang <kan.li...@intel.com>
Acked-by: Jiri Olsa <jo...@kernel.org>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Jin Yao <yao....@linux.intel.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Wang Nan <wangn...@huawei.com>
Link: 
http://lkml.kernel.org/r/1516310792-208685-12-git-send-email-kan.li...@intel.com
[ Renamed perf_top_overwrite_check to perf_top__overwrite_check, to follow 
existing convention ]
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
 tools/perf/builtin-top.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index c6ccda5..1778379 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -881,6 +881,68 @@ static void perf_top__mmap_read(struct perf_top *top)
                perf_top__mmap_read_idx(top, i);
 }
 
+/*
+ * Check per-event overwrite term.
+ * perf top should support consistent term for all events.
+ * - All events don't have per-event term
+ *   E.g. "cpu/cpu-cycles/,cpu/instructions/"
+ *   Nothing change, return 0.
+ * - All events have same per-event term
+ *   E.g. "cpu/cpu-cycles,no-overwrite/,cpu/instructions,no-overwrite/
+ *   Using the per-event setting to replace the opts->overwrite if
+ *   they are different, then return 0.
+ * - Events have different per-event term
+ *   E.g. "cpu/cpu-cycles,overwrite/,cpu/instructions,no-overwrite/"
+ *   Return -1
+ * - Some of the event set per-event term, but some not.
+ *   E.g. "cpu/cpu-cycles/,cpu/instructions,no-overwrite/"
+ *   Return -1
+ */
+static int perf_top__overwrite_check(struct perf_top *top)
+{
+       struct record_opts *opts = &top->record_opts;
+       struct perf_evlist *evlist = top->evlist;
+       struct perf_evsel_config_term *term;
+       struct list_head *config_terms;
+       struct perf_evsel *evsel;
+       int set, overwrite = -1;
+
+       evlist__for_each_entry(evlist, evsel) {
+               set = -1;
+               config_terms = &evsel->config_terms;
+               list_for_each_entry(term, config_terms, list) {
+                       if (term->type == PERF_EVSEL__CONFIG_TERM_OVERWRITE)
+                               set = term->val.overwrite ? 1 : 0;
+               }
+
+               /* no term for current and previous event (likely) */
+               if ((overwrite < 0) && (set < 0))
+                       continue;
+
+               /* has term for both current and previous event, compare */
+               if ((overwrite >= 0) && (set >= 0) && (overwrite != set))
+                       return -1;
+
+               /* no term for current event but has term for previous one */
+               if ((overwrite >= 0) && (set < 0))
+                       return -1;
+
+               /* has term for current event */
+               if ((overwrite < 0) && (set >= 0)) {
+                       /* if it's first event, set overwrite */
+                       if (evsel == perf_evlist__first(evlist))
+                               overwrite = set;
+                       else
+                               return -1;
+               }
+       }
+
+       if ((overwrite >= 0) && (opts->overwrite != overwrite))
+               opts->overwrite = overwrite;
+
+       return 0;
+}
+
 static int perf_top__start_counters(struct perf_top *top)
 {
        char msg[BUFSIZ];
@@ -888,6 +950,17 @@ static int perf_top__start_counters(struct perf_top *top)
        struct perf_evlist *evlist = top->evlist;
        struct record_opts *opts = &top->record_opts;
 
+       if (perf_top__overwrite_check(top)) {
+               ui__error("perf top only support consistent per-event "
+                         "overwrite setting for all events\n");
+               goto out_err;
+       }
+
+       if (opts->overwrite) {
+               ui__error("not support overwrite mode yet\n");
+               goto out_err;
+       }
+
        perf_evlist__config(evlist, opts, &callchain_param);
 
        evlist__for_each_entry(evlist, counter) {

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