[PATCH 18/75] perf mmap: Map data buffer for preserving collected data

Arnaldo Carvalho de Melo
2018-12-06T21:34:17Z

From: Alexey Budankov <alexey.budankov@linux.intel.com>

The map->data buffer is used to preserve map->base profiling data for
writing to disk. AIO map->cblock is used to queue corresponding
map->data buffer for asynchronous writing.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5fcda10c-6c63-68df-383a-c6d9e5d1f918@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/evlist.c | 2 +-
tools/perf/util/mmap.c | 49 +++++++++++++++++++++++++++++++++++++++-
tools/perf/util/mmap.h | 11 ++++++++-
3 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 36526d229315..6f010b9f0a81 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1028,7 +1028,7 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
* Its value is decided by evsel's write_backward.
* So &mp should not be passed through const pointer.
*/
- struct mmap_params mp;
+ struct mmap_params mp = { .nr_cblocks = 0 };

if (!evlist->mmap)
evlist->mmap = perf_evlist__alloc_mmap(evlist, false);
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index cdb95b3a1213..47cdc3ad6546 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -153,8 +153,55 @@ void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __mayb
{
}

+#ifdef HAVE_AIO_SUPPORT
+static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
+{
+ int delta_max;
+
+ if (mp->nr_cblocks) {
+ map->aio.data = malloc(perf_mmap__mmap_len(map));
+ if (!map->aio.data) {
+ pr_debug2("failed to allocate data buffer, error %m\n");
+ return -1;
+ }
+ /*
+ * Use cblock.aio_fildes value different from -1
+ * to denote started aio write operation on the
+ * cblock so it requires explicit record__aio_sync()
+ * call prior the cblock may be reused again.
+ */
+ map->aio.cblock.aio_fildes = -1;
+ /*
+ * Allocate cblock with max priority delta to
+ * have faster aio write system calls.
+ */
+ delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
+ map->aio.cblock.aio_reqprio = delta_max;
+ }
+
+ return 0;
+}
+
+static void perf_mmap__aio_munmap(struct perf_mmap *map)
+{
+ if (map->aio.data)
+ zfree(&map->aio.data);
+}
+#else
+static int perf_mmap__aio_mmap(struct perf_mmap *map __maybe_unused,
+ struct mmap_params *mp __maybe_unused)
+{
+ return 0;
+}
+
+static void perf_mmap__aio_munmap(struct perf_mmap *map __maybe_unused)
+{
+}
+#endif
+
void perf_mmap__munmap(struct perf_mmap *map)
{
+ perf_mmap__aio_munmap(map);
if (map->base != NULL) {
munmap(map->base, perf_mmap__mmap_len(map));
map->base = NULL;
@@ -197,7 +244,7 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int c
&mp->auxtrace_mp, map->base, fd))
return -1;

- return 0;
+ return perf_mmap__aio_mmap(map, mp);
}

static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index cc5e2d6d17a9..3f10ad030c5e 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -6,6 +6,9 @@
#include <linux/types.h>
#include <linux/ring_buffer.h>
#include <stdbool.h>
+#ifdef HAVE_AIO_SUPPORT
+#include <aio.h>
+#endif
#include "auxtrace.h"
#include "event.h"

@@ -26,6 +29,12 @@ struct perf_mmap {
bool overwrite;
struct auxtrace_mmap auxtrace_mmap;
char event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
+#ifdef HAVE_AIO_SUPPORT
+ struct {
+ void *data;
+ struct aiocb cblock;
+ } aio;
+#endif
};

/*
@@ -57,7 +66,7 @@ enum bkw_mmap_state {
};

struct mmap_params {
- int prot, mask;
+ int prot, mask, nr_cblocks;
struct auxtrace_mmap_params auxtrace_mp;
};

--
2.19.2