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    Subject[PATCH V5 11/17] perf top: check per-event overwrite term
    Date
    From: Kan Liang <kan.liang@intel.com>

    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.liang@intel.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..c86eee4 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) {
    --
    2.5.5
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