display-average-commit-time

   1 ext4: display average commit time
   2
   3 Display the average commit time (which is used by the ext4 fsync
   4 batching patch) in /proc/fs/jbd2/*/info for performance tuning
   5 purposes.
   6
   7 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
   8 diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
   9 index e70d657..52f012b 100644
  10 --- a/fs/jbd2/journal.c
  11 +++ b/fs/jbd2/journal.c
  12 @@ -40,6 +40,7 @@
  13
  14  #include <asm/uaccess.h>
  15  #include <asm/page.h>
  16 +#include <asm/div64.h>
  17
  18  EXPORT_SYMBOL(jbd2_journal_start);
  19  EXPORT_SYMBOL(jbd2_journal_restart);
  20 @@ -824,6 +825,8 @@ static int jbd2_seq_info_show(struct seq_file *seq, void *v)
  21             jiffies_to_msecs(s->stats->u.run.rs_flushing / s->stats->ts_tid));
  22         seq_printf(seq, "  %ums logging transaction\n",
  23             jiffies_to_msecs(s->stats->u.run.rs_logging / s->stats->ts_tid));
  24 +       seq_printf(seq, "  %lluus average transaction commit time\n",
  25 +                  do_div(s->journal->j_average_commit_time, 1000));
  26         seq_printf(seq, "  %lu handles per transaction\n",
  27             s->stats->u.run.rs_handle_count / s->stats->ts_tid);
  28         seq_printf(seq, "  %lu blocks per transaction\n",