perf evlist: Steal mmap reading routine from 'perf top'

Will be used in the upcoming 'perf test' entry for the evlist mmap
routines.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index df85c1f9417b55366d4256c76b16f0f4900306b4..58352ad807c75cda3d4cdaff4b3da60aa21c9ae0 100644 (file)
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1100,67 +1100,17 @@ static void event__process_sample(const event_t *self,
 
 static void perf_session__mmap_read_cpu(struct perf_session *self, int cpu)
 {
-       struct perf_mmap *md = &evsel_list->mmap[cpu];
-       unsigned int head = perf_mmap__read_head(md);
-       unsigned int old = md->prev;
-       unsigned char *data = md->base + page_size;
        struct sample_data sample;
-       int diff;
-
-       /*
-        * If we're further behind than half the buffer, there's a chance
-        * the writer will bite our tail and mess up the samples under us.
-        *
-        * If we somehow ended up ahead of the head, we got messed up.
-        *
-        * In either case, truncate and restart at head.
-        */
-       diff = head - old;
-       if (diff > md->mask / 2 || diff < 0) {
-               fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");
-
-               /*
-                * head points to a known good entry, start there.
-                */
-               old = head;
-       }
-
-       for (; old != head;) {
-               event_t *event = (event_t *)&data[old & md->mask];
-
-               event_t event_copy;
-
-               size_t size = event->header.size;
-
-               /*
-                * Event straddles the mmap boundary -- header should always
-                * be inside due to u64 alignment of output.
-                */
-               if ((old & md->mask) + size != ((old + size) & md->mask)) {
-                       unsigned int offset = old;
-                       unsigned int len = min(sizeof(*event), size), cpy;
-                       void *dst = &event_copy;
-
-                       do {
-                               cpy = min(md->mask + 1 - (offset & md->mask), len);
-                               memcpy(dst, &data[offset & md->mask], cpy);
-                               offset += cpy;
-                               dst += cpy;
-                               len -= cpy;
-                       } while (len);
-
-                       event = &event_copy;
-               }
+       event_t *event;
 
+       while ((event = perf_evlist__read_on_cpu(evsel_list, cpu)) != NULL) {
                event__parse_sample(event, self, &sample);
+
                if (event->header.type == PERF_RECORD_SAMPLE)
                        event__process_sample(event, &sample, self);
                else
                        event__process(event, &sample, self);
-               old += size;
        }
-
-       md->prev = old;
 }
 
 static void perf_session__mmap_read(struct perf_session *self)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index deb82a4fc3128bdab9647bcf939d01395e3e9523..4b3b84cd71a129145030581e9db922c330bfb4f5 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -95,3 +95,65 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
                        return sid->evsel;
        return NULL;
 }
+
+event_t *perf_evlist__read_on_cpu(struct perf_evlist *evlist, int cpu)
+{
+       /* XXX Move this to perf.c, making it generally available */
+       unsigned int page_size = sysconf(_SC_PAGE_SIZE);
+       struct perf_mmap *md = &evlist->mmap[cpu];
+       unsigned int head = perf_mmap__read_head(md);
+       unsigned int old = md->prev;
+       unsigned char *data = md->base + page_size;
+       event_t *event = NULL;
+       int diff;
+
+       /*
+        * If we're further behind than half the buffer, there's a chance
+        * the writer will bite our tail and mess up the samples under us.
+        *
+        * If we somehow ended up ahead of the head, we got messed up.
+        *
+        * In either case, truncate and restart at head.
+        */
+       diff = head - old;
+       if (diff > md->mask / 2 || diff < 0) {
+               fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");
+
+               /*
+                * head points to a known good entry, start there.
+                */
+               old = head;
+       }
+
+       if (old != head) {
+               size_t size;
+
+               event = (event_t *)&data[old & md->mask];
+               size = event->header.size;
+
+               /*
+                * Event straddles the mmap boundary -- header should always
+                * be inside due to u64 alignment of output.
+                */
+               if ((old & md->mask) + size != ((old + size) & md->mask)) {
+                       unsigned int offset = old;
+                       unsigned int len = min(sizeof(*event), size), cpy;
+                       void *dst = &evlist->event_copy;
+
+                       do {
+                               cpy = min(md->mask + 1 - (offset & md->mask), len);
+                               memcpy(dst, &data[offset & md->mask], cpy);
+                               offset += cpy;
+                               dst += cpy;
+                               len -= cpy;
+                       } while (len);
+
+                       event = &evlist->event_copy;
+               }
+
+               old += size;
+       }
+
+       md->prev = old;
+       return event;
+}

diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index dbfcc79bb9959d1c58b2f5a9c3b91ed575ade314..28712063db97a57958da7cb1b122e424e604514c 100644 (file)
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -3,6 +3,7 @@
 
 #include <linux/list.h>
 #include "../perf.h"
+#include "event.h"
 
 struct pollfd;
 
@@ -15,6 +16,7 @@ struct perf_evlist {
        int              nr_entries;
        int              nr_fds;
        int              mmap_len;
+       event_t          event_copy;
        struct perf_mmap *mmap;
        struct pollfd    *pollfd;
 };
@@ -32,4 +34,6 @@ void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd);
 
 struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id);
 
+event_t *perf_evlist__read_on_cpu(struct perf_evlist *self, int cpu);
+
 #endif /* __PERF_EVLIST_H */