perf header: Add HEADER_GROUP_DESC feature

Save group relationship information so that it can be restored when perf
report is running.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1358845787-1350-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 2ac690c..774c907 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -486,6 +486,9 @@ 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 f6081cb..8022b52 100644 (file)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1085,6 +1085,52 @@ 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;
+       int ret;
+
+       ret = do_write(fd, &nr_groups, sizeof(nr_groups));
+       if (ret < 0)
+               return ret;
+
+       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;
+
+                       ret = do_write_string(fd, name);
+                       if (ret < 0)
+                               return ret;
+
+                       ret = do_write(fd, &leader_idx, sizeof(leader_idx));
+                       if (ret < 0)
+                               return ret;
+
+                       ret = do_write(fd, &nr_members, sizeof(nr_members));
+                       if (ret < 0)
+                               return ret;
+               }
+       }
+       return 0;
+}
+
+/*
  * default get_cpuid(): nothing gets recorded
  * actual implementation must be in arch/$(ARCH)/util/header.c
  */
@@ -1447,6 +1493,31 @@ 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)
@@ -1961,6 +2032,98 @@ 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 (readn(fd, &nr_groups, sizeof(nr_groups)) != sizeof(nr_groups))
+               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 (readn(fd, &desc[i].leader_idx, sizeof(u32)) != sizeof(u32))
+                       goto out_free;
+
+               if (readn(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);
@@ -2000,6 +2163,7 @@ 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 20f0344..c9fc55c 100644 (file)
--- 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 {