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authorTheodore Ts'o <tytso@mit.edu>2013-02-06 22:30:23 -0500
committerTheodore Ts'o <tytso@mit.edu>2013-02-06 22:30:23 -0500
commit9fff24aa2c5c504aadead1ff9599e813604c2e53 (patch)
tree24bbb1691ec816aed648a895882526ce361ec92f /fs/jbd2/journal.c
parent40ae3487628235e5f1eb27542cca0cdb6e5dbe16 (diff)
jbd2: track request delay statistics
Track the delay between when we first request that the commit begin and when it actually begins, so we can see how much of a gap exists. In theory, this should just be the remaining scheduling quantuum of the thread which requested the commit (assuming it was not a synchronous operation which triggered the commit request) plus scheduling overhead; however, it's possible that real time processes might get in the way of letting the kjournald thread from executing. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/jbd2/journal.c')
-rw-r--r--fs/jbd2/journal.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 1a80e3146a59..4ba2e81e35ac 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -533,6 +533,7 @@ int __jbd2_log_start_commit(journal_t *journal, tid_t target)
jbd_debug(1, "JBD2: requesting commit %d/%d\n",
journal->j_commit_request,
journal->j_commit_sequence);
+ journal->j_running_transaction->t_requested = jiffies;
wake_up(&journal->j_wait_commit);
return 1;
} else if (!tid_geq(journal->j_commit_request, target))
@@ -898,13 +899,18 @@ static int jbd2_seq_info_show(struct seq_file *seq, void *v)
if (v != SEQ_START_TOKEN)
return 0;
- seq_printf(seq, "%lu transaction, each up to %u blocks\n",
- s->stats->ts_tid,
- s->journal->j_max_transaction_buffers);
+ seq_printf(seq, "%lu transactions (%lu requested), "
+ "each up to %u blocks\n",
+ s->stats->ts_tid, s->stats->ts_requested,
+ s->journal->j_max_transaction_buffers);
if (s->stats->ts_tid == 0)
return 0;
seq_printf(seq, "average: \n %ums waiting for transaction\n",
jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
+ seq_printf(seq, " %ums request delay\n",
+ (s->stats->ts_requested == 0) ? 0 :
+ jiffies_to_msecs(s->stats->run.rs_request_delay /
+ s->stats->ts_requested));
seq_printf(seq, " %ums running transaction\n",
jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
seq_printf(seq, " %ums transaction was being locked\n",