Re: [PATCH] lockstat: report avg wait and hold times

[Ingo Molnar <mingo@kernel.org>]

* Davidlohr Bueso <davidlohr@hp.com> wrote:

> While both the nr and total times are showed, having the avg lock hold
> and wait times show in the report is quite useful when working on
> performance related issues. Furthermore, I find myself constantly
> doing the calculations manually.
> 
> In addition, some of the documentation examples were changed to easily
> update them to show the two new columns. No textual change otherwise,
> as descriptions match the lockstat output.

Looks useful.

> --- a/kernel/lockdep_proc.c
> +++ b/kernel/lockdep_proc.c
> @@ -421,6 +421,7 @@ static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
>  	seq_time(m, lt->min);
>  	seq_time(m, lt->max);
>  	seq_time(m, lt->total);
> +	seq_time(m, lt->nr ? lt->total/lt->nr : 0);

That won't build on 32-bit systems as lt->total is s64.

You'll need to utilize do_div().

Thanks,

	Ingo