On Aug 01, 2008 09:25 -0400, Josef Bacik wrote:
> + if (unlikely(!journal->j_average_commit_time))
> + journal->j_average_commit_time = commit_time;
> + else
> + journal->j_average_commit_time = (commit_time +
> + journal->j_average_commit_time) / 2;
You may also consider making this a decaying average, so that minor changes
in the workload are smoothed out. Also, it is probably easier to read
likely(foo) instead of unlikely(!foo)...
if (likely(journal->j_average_commit_time != 0))
journal->j_average_commit_time =
(commit_time * 3 + journal->j_average_commit_time) / 4;
else
journal->j_average_commit_time = commit_time;
> + if (journal->print_count < 100) {
> + journal->print_count++;
> + printk(KERN_ERR "avg commit time = %lu\n",
> + journal->j_average_commit_time);
> + }
There is already the jbd stats patch in jbd2 that is reporting this
information for the previous transactions.
>
> + spin_lock(&journal->j_state_lock);
> + commit_time = journal->j_average_commit_time;
> + spin_unlock(&journal->j_state_lock);
> +
> + sleep_time = elapsed_jiffies(transaction->t_start_time, jiffies);
> + if (!sleep_time)
> + sleep_time = 1;
> + sleep_time = (commit_time / sleep_time) * commit_time;
I was also going to comment on the use of jiffies here, but Ric beat me
to it.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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