perf data: Add perf_data_file__switch() helper

perf_data_file__switch() closes current output file, renames it, then
open a new one to continue recording. It will be used by 'perf record'
to split output into multiple perf.data files.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1460535673-159866-3-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 1921942fc2e035cb2ddec0ba94b066e02a8f5bc9..be83516155ee5d7914d699b48df33441b7f6f345 100644 (file)
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -136,3 +136,44 @@ ssize_t perf_data_file__write(struct perf_data_file *file,
 {
        return writen(file->fd, buf, size);
 }
+
+int perf_data_file__switch(struct perf_data_file *file,
+                          const char *postfix,
+                          size_t pos, bool at_exit)
+{
+       char *new_filepath;
+       int ret;
+
+       if (check_pipe(file))
+               return -EINVAL;
+       if (perf_data_file__is_read(file))
+               return -EINVAL;
+
+       if (asprintf(&new_filepath, "%s.%s", file->path, postfix) < 0)
+               return -ENOMEM;
+
+       /*
+        * Only fire a warning, don't return error, continue fill
+        * original file.
+        */
+       if (rename(file->path, new_filepath))
+               pr_warning("Failed to rename %s to %s\n", file->path, new_filepath);
+
+       if (!at_exit) {
+               close(file->fd);
+               ret = perf_data_file__open(file);
+               if (ret < 0)
+                       goto out;
+
+               if (lseek(file->fd, pos, SEEK_SET) == (off_t)-1) {
+                       ret = -errno;
+                       pr_debug("Failed to lseek to %zu: %s",
+                                pos, strerror(errno));
+                       goto out;
+               }
+       }
+       ret = file->fd;
+out:
+       free(new_filepath);
+       return ret;
+}

diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index 2b15d0c95c7f312de08a36a05b08c8356b039616..ae510ce16cb1277721bd132438c08311febb7156 100644 (file)
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -46,5 +46,14 @@ int perf_data_file__open(struct perf_data_file *file);
 void perf_data_file__close(struct perf_data_file *file);
 ssize_t perf_data_file__write(struct perf_data_file *file,
                              void *buf, size_t size);
-
+/*
+ * If at_exit is set, only rename current perf.data to
+ * perf.data.<postfix>, continue write on original file.
+ * Set at_exit when flushing the last output.
+ *
+ * Return value is fd of new output.
+ */
+int perf_data_file__switch(struct perf_data_file *file,
+                          const char *postfix,
+                          size_t pos, bool at_exit);
 #endif /* __PERF_DATA_H */