perf tools: Add pmu mappings to header information

With dynamic pmu allocation there are also dynamically assigned pmu ids.
These ids are used in event->attr.type to describe the pmu to be used
for that event. The information is available in sysfs, e.g:

 /sys/bus/event_source/devices/breakpoint/type: 5
 /sys/bus/event_source/devices/cpu/type: 4
 /sys/bus/event_source/devices/ibs_fetch/type: 6
 /sys/bus/event_source/devices/ibs_op/type: 7
 /sys/bus/event_source/devices/software/type: 1
 /sys/bus/event_source/devices/tracepoint/type: 2

These mappings are needed to know which samples belong to which pmu.  If
a pmu is added dynamically like for ibs_fetch or ibs_op the type value
may vary.

Now, when decoding samples from perf.data this information in sysfs
might be no longer available or may have changed. We need to store it in
perf.data. Using the header for this. Now the header information created
with perf report contains an additional section looking like this:

 # pmu mappings: ibs_op = 7, ibs_fetch = 6, cpu = 4, breakpoint = 5, tracepoint = 2, software = 1

Signed-off-by: Robert Richter <robert.richter@amd.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1345144224-27280-9-git-send-email-robert.richter@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 48 insertions, 2 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 67715a42cd6d..6631d828db3d 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -10,6 +10,8 @@
 #include "pmu.h"
 #include "parse-events.h"
 
+#define EVENT_SOURCE_DEVICE_PATH "/bus/event_source/devices/"
+
 int perf_pmu_parse(struct list_head *list, char *name);
 extern FILE *perf_pmu_in;
 
@@ -69,7 +71,7 @@ static int pmu_format(char *name, struct list_head *format)
                 return -1;
 
         snprintf(path, PATH_MAX,
-                 "%s/bus/event_source/devices/%s/format", sysfs, name);
+                 "%s" EVENT_SOURCE_DEVICE_PATH "%s/format", sysfs, name);
 
         if (stat(path, &st) < 0)
                 return 0;       /* no error if format does not exist */
@@ -206,7 +208,7 @@ static int pmu_type(char *name, __u32 *type)
                 return -1;
 
         snprintf(path, PATH_MAX,
-                 "%s/bus/event_source/devices/%s/type", sysfs, name);
+                 "%s" EVENT_SOURCE_DEVICE_PATH "%s/type", sysfs, name);
 
         if (stat(path, &st) < 0)
                 return -1;
@@ -222,6 +224,35 @@ static int pmu_type(char *name, __u32 *type)
         return ret;
 }
 
+/* Add all pmus in sysfs to pmu list: */
+static void pmu_read_sysfs(void)
+{
+        char path[PATH_MAX];
+        const char *sysfs;
+        DIR *dir;
+        struct dirent *dent;
+
+        sysfs = sysfs_find_mountpoint();
+        if (!sysfs)
+                return;
+
+        snprintf(path, PATH_MAX,
+                 "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);
+
+        dir = opendir(path);
+        if (!dir)
+                return;
+
+        while ((dent = readdir(dir))) {
+                if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
+                        continue;
+                /* add to static LIST_HEAD(pmus): */
+                perf_pmu__find(dent->d_name);
+        }
+
+        closedir(dir);
+}
+
 static struct perf_pmu *pmu_lookup(char *name)
 {
         struct perf_pmu *pmu;
@@ -267,6 +298,21 @@ static struct perf_pmu *pmu_find(char *name)
         return NULL;
 }
 
+struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu)
+{
+        /*
+         * pmu iterator: If pmu is NULL, we start at the begin,
+         * otherwise return the next pmu. Returns NULL on end.
+         */
+        if (!pmu) {
+                pmu_read_sysfs();
+                pmu = list_prepare_entry(pmu, &pmus, list);
+        }
+        list_for_each_entry_continue(pmu, &pmus, list)
+                return pmu;
+        return NULL;
+}
+
 struct perf_pmu *perf_pmu__find(char *name)
 {
         struct perf_pmu *pmu;