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Message-ID: <20121129184304.GB1957@ghostprotocols.net>
Date: Thu, 29 Nov 2012 15:43:04 -0300
From: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Paul Mackerras <paulus@...ba.org>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
Jiri Olsa <jolsa@...hat.com>,
Stephane Eranian <eranian@...gle.com>,
Andi Kleen <andi@...stfloor.org>,
Namhyung Kim <namhyung.kim@....com>
Subject: Re: [PATCH 04/18] perf header: Add HEADER_GROUP_DESC feature
Em Thu, Nov 29, 2012 at 03:38:32PM +0900, Namhyung Kim escreveu:
> From: Namhyung Kim <namhyung.kim@....com>
>
> Save group relationship information so that it can be restored when
> perf report is running.
>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Cc: Stephane Eranian <eranian@...gle.com>
> Acked-by: Jiri Olsa <jolsa@...hat.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
> tools/perf/builtin-record.c | 3 +
> tools/perf/util/header.c | 153 ++++++++++++++++++++++++++++++++++++++++++++
> tools/perf/util/header.h | 2 +
> 3 files changed, 158 insertions(+)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index f3151d3c70ce..d50f0dcfe1c1 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -592,6 +592,9 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
> goto out_delete_session;
> }
>
> + if (!evsel_list->nr_groups)
> + perf_header__clear_feat(&session->header, HEADER_GROUP_DESC);
> +
> /*
> * perf_session__delete(session) will be called at perf_record__exit()
> */
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 195a47a8f052..6ae8185842f2 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1073,6 +1073,41 @@ static int write_pmu_mappings(int fd, struct perf_header *h __maybe_unused,
> }
>
> /*
> + * File format:
> + *
> + * struct group_descs {
> + * u32 nr_groups;
> + * struct group_desc {
> + * char name[];
> + * u32 leader_idx;
> + * u32 nr_members;
> + * }[nr_groups];
> + * };
> + */
> +static int write_group_desc(int fd, struct perf_header *h __maybe_unused,
> + struct perf_evlist *evlist)
> +{
> + u32 nr_groups = evlist->nr_groups;
> + struct perf_evsel *evsel;
> +
> + do_write(fd, &nr_groups, sizeof(nr_groups));
> +
> + list_for_each_entry(evsel, &evlist->entries, node) {
> + if (perf_evsel__is_group_leader(evsel) &&
> + evsel->nr_members > 1) {
> + const char *name = evsel->group_name ?: "{anon_group}";
> + u32 leader_idx = evsel->idx;
> + u32 nr_members = evsel->nr_members;
> +
> + do_write_string(fd, name);
> + do_write(fd, &leader_idx, sizeof(leader_idx));
> + do_write(fd, &nr_members, sizeof(nr_members));
You need to check do_write() return, it can fail. There are some cases
in header.c that don't check it, those should be eventually fixed, most
cases check it tho.
> + }
> + }
> + return 0;
> +}
> +
> +/*
> * default get_cpuid(): nothing gets recorded
> * actual implementation must be in arch/$(ARCH)/util/header.c
> */
> @@ -1433,6 +1468,31 @@ error:
> fprintf(fp, "# pmu mappings: unable to read\n");
> }
>
> +static void print_group_desc(struct perf_header *ph, int fd __maybe_unused,
> + FILE *fp)
> +{
> + struct perf_session *session;
> + struct perf_evsel *evsel;
> + u32 nr = 0;
> +
> + session = container_of(ph, struct perf_session, header);
> +
> + list_for_each_entry(evsel, &session->evlist->entries, node) {
> + if (perf_evsel__is_group_leader(evsel) &&
> + evsel->nr_members > 1) {
> + fprintf(fp, "# group: %s{%s", evsel->group_name ?: "",
> + perf_evsel__name(evsel));
> +
> + nr = evsel->nr_members - 1;
> + } else if (nr) {
> + fprintf(fp, ",%s", perf_evsel__name(evsel));
> +
> + if (--nr == 0)
> + fprintf(fp, "}\n");
> + }
> + }
> +}
> +
> static int __event_process_build_id(struct build_id_event *bev,
> char *filename,
> struct perf_session *session)
> @@ -1947,6 +2007,98 @@ error:
> return -1;
> }
>
> +static int process_group_desc(struct perf_file_section *section __maybe_unused,
> + struct perf_header *ph, int fd,
> + void *data __maybe_unused)
> +{
> + size_t ret = -1;
> + u32 i, nr, nr_groups;
> + struct perf_session *session;
> + struct perf_evsel *evsel, *leader = NULL;
> + struct group_desc {
> + char *name;
> + u32 leader_idx;
> + u32 nr_members;
> + } *desc;
> +
> + if (read(fd, &nr_groups, sizeof(nr_groups)) != sizeof(nr_groups))
Please use readn() instead in all read() cases in this function.
> + return -1;
> +
> + if (ph->needs_swap)
> + nr_groups = bswap_32(nr_groups);
> +
> + ph->env.nr_groups = nr_groups;
> + if (!nr_groups) {
> + pr_debug("group desc not available\n");
> + return 0;
> + }
> +
> + desc = calloc(nr_groups, sizeof(*desc));
> + if (!desc)
> + return -1;
> +
> + for (i = 0; i < nr_groups; i++) {
> + desc[i].name = do_read_string(fd, ph);
> + if (!desc[i].name)
> + goto out_free;
> +
> + if (read(fd, &desc[i].leader_idx, sizeof(u32)) != sizeof(u32))
> + goto out_free;
> +
> + if (read(fd, &desc[i].nr_members, sizeof(u32)) != sizeof(u32))
> + goto out_free;
> +
> + if (ph->needs_swap) {
> + desc[i].leader_idx = bswap_32(desc[i].leader_idx);
> + desc[i].nr_members = bswap_32(desc[i].nr_members);
> + }
> + }
> +
> + /*
> + * Rebuild group relationship based on the group_desc
> + */
> + session = container_of(ph, struct perf_session, header);
> + session->evlist->nr_groups = nr_groups;
> +
> + i = nr = 0;
> + list_for_each_entry(evsel, &session->evlist->entries, node) {
> + if (evsel->idx == (int) desc[i].leader_idx) {
> + evsel->leader = evsel;
> + /* {anon_group} is a dummy name */
> + if (strcmp(desc[i].name, "{anon_group}"))
> + evsel->group_name = desc[i].name;
> + evsel->nr_members = desc[i].nr_members;
> +
> + if (i >= nr_groups || nr > 0) {
> + pr_debug("invalid group desc\n");
> + goto out_free;
> + }
> +
> + leader = evsel;
> + nr = evsel->nr_members - 1;
> + i++;
> + } else if (nr) {
> + /* This is a group member */
> + evsel->leader = leader;
> +
> + nr--;
> + }
> + }
> +
> + if (i != nr_groups || nr != 0) {
> + pr_debug("invalid group desc\n");
> + goto out_free;
> + }
> +
> + ret = 0;
> +out_free:
> + while ((int) --i >= 0)
> + free(desc[i].name);
> + free(desc);
> +
> + return ret;
> +}
> +
> struct feature_ops {
> int (*write)(int fd, struct perf_header *h, struct perf_evlist *evlist);
> void (*print)(struct perf_header *h, int fd, FILE *fp);
> @@ -1986,6 +2138,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
> FEAT_OPF(HEADER_NUMA_TOPOLOGY, numa_topology),
> FEAT_OPA(HEADER_BRANCH_STACK, branch_stack),
> FEAT_OPP(HEADER_PMU_MAPPINGS, pmu_mappings),
> + FEAT_OPP(HEADER_GROUP_DESC, group_desc),
> };
>
> struct header_print_data {
> diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
> index 5f1cd6884f37..e3e7fb490310 100644
> --- a/tools/perf/util/header.h
> +++ b/tools/perf/util/header.h
> @@ -29,6 +29,7 @@ enum {
> HEADER_NUMA_TOPOLOGY,
> HEADER_BRANCH_STACK,
> HEADER_PMU_MAPPINGS,
> + HEADER_GROUP_DESC,
> HEADER_LAST_FEATURE,
> HEADER_FEAT_BITS = 256,
> };
> @@ -79,6 +80,7 @@ struct perf_session_env {
> char *numa_nodes;
> int nr_pmu_mappings;
> char *pmu_mappings;
> + int nr_groups;
> };
>
> struct perf_header {
> --
> 1.7.11.7
--
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