perf record: Refine capture printout

Print out the number of bytes captured, and the (estimated) number of
events the output file contains.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 24 insertions, 10 deletions

diff --git a/Documentation/perf_counter/builtin-record.c b/Documentation/perf_counter/builtin-record.c
index fa625258315e..efa2eb498e9c 100644
--- a/Documentation/perf_counter/builtin-record.c
+++ b/Documentation/perf_counter/builtin-record.c
@@ -67,6 +67,8 @@ static unsigned int mmap_read_head(struct mmap_data *md)
 static long events;
 static struct timeval last_read, this_read;
 
+static __u64 bytes_written;
+
 static void mmap_read(struct mmap_data *md)
 {
         unsigned int head = mmap_read_head(md);
@@ -114,28 +116,34 @@ static void mmap_read(struct mmap_data *md)
                 buf = &data[old & md->mask];
                 size = md->mask + 1 - (old & md->mask);
                 old += size;
+
                 while (size) {
                         int ret = write(output, buf, size);
-                        if (ret < 0) {
-                                perror("failed to write");
-                                exit(-1);
-                        }
+
+                        if (ret < 0)
+                                die("failed to write");
+
                         size -= ret;
                         buf += ret;
+
+                        bytes_written += ret;
                 }
         }
 
         buf = &data[old & md->mask];
         size = head - old;
         old += size;
+
         while (size) {
                 int ret = write(output, buf, size);
-                if (ret < 0) {
-                        perror("failed to write");
-                        exit(-1);
-                }
+
+                if (ret < 0)
+                        die("failed to write");
+
                 size -= ret;
                 buf += ret;
+
+                bytes_written += ret;
         }
 
         md->prev = old;
@@ -467,8 +475,14 @@ static int __cmd_record(int argc, const char **argv)
                         ret = poll(event_array, nr_poll, 100);
         }
 
-
-        fprintf(stderr, "[ perf record: Captured and wrote %ld events. ]\n", events);
+        /*
+         * Approximate RIP event size: 24 bytes.
+         */
+        fprintf(stderr,
+                "[ perf record: Captured and wrote %.3f MB %s (~%lld events) ]\n",
+                (double)bytes_written / 1024.0 / 1024.0,
+                output_name,
+                bytes_written / 24);
 
         return 0;
 }