[tip:perf/core] perf evlist: Steal mmap reading routine from 'perf top'

tip-bot for Arnaldo Carvalho de Melo
2011-01-26T07:20:05Z

Commit-ID: 04391debc3e1195222a4dbb162ace6542dd89c1c
Gitweb: http://git.kernel.org/tip/04391debc3e1195222a4dbb162ace6542dd89c1c
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Sat, 15 Jan 2011 10:40:59 -0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Sat, 22 Jan 2011 19:56:30 -0200

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>
---
tools/perf/builtin-top.c | 56 ++---------------------------------------
tools/perf/util/evlist.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/evlist.h | 4 +++
3 files changed, 69 insertions(+), 53 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index df85c1f..58352ad 100644
--- 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 deb82a4..4b3b84c 100644
--- 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 dbfcc79..2871206 100644
--- 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 */