[tip: perf/core] perf data: Support single perf.data file directory

From: tip-bot2 for Adrian Hunter
Date: Tue Nov 12 2019 - 06:20:01 EST


The following commit has been merged into the perf/core branch of tip:

Commit-ID: 46e201efa15b70ec39df5237116fddebb4f5057c
Gitweb: https://git.kernel.org/tip/46e201efa15b70ec39df5237116fddebb4f5057c
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Fri, 04 Oct 2019 11:31:20 +03:00
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Wed, 06 Nov 2019 15:43:05 -03:00

perf data: Support single perf.data file directory

Support directory output that contains a regular perf.data file, named
"data". By default the directory is named perf.data i.e.
perf.data
âââ data

Most of the infrastructure to support a directory is already there. This
patch makes the changes needed to support the format above.

Presently there is no 'perf record' option to output a directory.

This is preparation for adding support for putting a copy of /proc/kcore in
the directory.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20191004083121.12182-5-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf.data-directory-format.txt | 28 ++++++++-
tools/perf/builtin-record.c | 2 +-
tools/perf/util/data.c | 9 ++-
tools/perf/util/data.h | 6 ++-
4 files changed, 43 insertions(+), 2 deletions(-)
create mode 100644 tools/perf/Documentation/perf.data-directory-format.txt

diff --git a/tools/perf/Documentation/perf.data-directory-format.txt b/tools/perf/Documentation/perf.data-directory-format.txt
new file mode 100644
index 0000000..4bf0890
--- /dev/null
+++ b/tools/perf/Documentation/perf.data-directory-format.txt
@@ -0,0 +1,28 @@
+perf.data directory format
+
+DISCLAIMER This is not ABI yet and is subject to possible change
+ in following versions of perf. We will remove this
+ disclaimer once the directory format soaks in.
+
+
+This document describes the on-disk perf.data directory format.
+
+The layout is described by HEADER_DIR_FORMAT feature.
+Currently it holds only version number (0):
+
+ HEADER_DIR_FORMAT = 24
+
+ struct {
+ uint64_t version;
+ }
+
+The current only version value 0 means that:
+ - there is a single perf.data file named 'data' within the directory.
+ e.g.
+
+ $ tree -ps perf.data
+ perf.data
+ âââ [-rw------- 25912] data
+
+Future versions are expected to describe different data files
+layout according to special needs.
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 2fb83aa..e402459 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -537,7 +537,7 @@ static int record__process_auxtrace(struct perf_tool *tool,
size_t padding;
u8 pad[8] = {0};

- if (!perf_data__is_pipe(data) && !perf_data__is_dir(data)) {
+ if (!perf_data__is_pipe(data) && perf_data__is_single_file(data)) {
off_t file_offset;
int fd = perf_data__fd(data);
int err;
diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index df173f0..964ea10 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -76,6 +76,13 @@ int perf_data__open_dir(struct perf_data *data)
DIR *dir;
int nr = 0;

+ /*
+ * Directory containing a single regular perf data file which is already
+ * open, means there is nothing more to do here.
+ */
+ if (perf_data__is_single_file(data))
+ return 0;
+
if (WARN_ON(!data->is_dir))
return -EINVAL;

@@ -406,7 +413,7 @@ unsigned long perf_data__size(struct perf_data *data)
u64 size = data->file.size;
int i;

- if (!data->is_dir)
+ if (perf_data__is_single_file(data))
return size;

for (i = 0; i < data->dir.nr; i++) {
diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index 218fe9a..f68815f 100644
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -10,6 +10,7 @@ enum perf_data_mode {
};

enum perf_dir_version {
+ PERF_DIR_SINGLE_FILE = 0,
PERF_DIR_VERSION = 1,
};

@@ -54,6 +55,11 @@ static inline bool perf_data__is_dir(struct perf_data *data)
return data->is_dir;
}

+static inline bool perf_data__is_single_file(struct perf_data *data)
+{
+ return data->dir.version == PERF_DIR_SINGLE_FILE;
+}
+
static inline int perf_data__fd(struct perf_data *data)
{
return data->file.fd;