Re: [RFC PATCH] pack-objects: write objects packed to trace2

[Jeff Hostetler <git@jeffhostetler.com>]

On 4/9/2019 5:44 PM, Jonathan Tan wrote:
> This is useful when investigating performance of pushes, and other times
> when no progress information is written (because the pack is written to
> stdout).
> 
> Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
> ---
> We're trying to improve push performance, and it would be nice to be
> able to observe the number of objects sent over each push, both to
> correlate it with time taken (which is already traced) and to notice
> situations when significantly more objects are being sent than needed.
> 
> Sending this as an RFC because this patch works but is somewhat ad-hoc -
> perhaps someone else has a more comprehensive solution.
> ---
>   builtin/pack-objects.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
> index a154fc29f6..ac464d7d07 100644
> --- a/builtin/pack-objects.c
> +++ b/builtin/pack-objects.c
> @@ -964,6 +964,7 @@ static void write_pack_file(void)
>   	if (written != nr_result)
>   		die(_("wrote %"PRIu32" objects while expecting %"PRIu32),
>   		    written, nr_result);
> +	trace2_printf("packed %d objects", nr_result);

For a simple field like this, you might want to use:

	trace2_data_intmax("pack-objects", the_repository,
			   "write_pack_file/wrote", nr_result);

This will give your message visibility in both the perf and event
targets.  The latter makes it easier for post-processing.

jeff