From: Jeff Hostetler <git@jeffhostetler.com>
Date: Tue, 11 May 2021 16:17:09 GMT
Subject: Re: [PATCH v3 1/8] [RFC] dir: convert trace calls to trace2 equivalents
Message-ID: <96679919-f6ea-adcc-b8fc-9eaa0134c876@jeffhostetler.com>
In-Reply-To: <9f1c0d78d739cc1da8517eea92e81a7bd162578f.1620503945.git.gitgitgadget@gmail.com>



On 5/8/21 3:58 PM, Elijah Newren via GitGitGadget wrote:
> From: Elijah Newren <newren@gmail.com>
> 
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
>   dir.c                             |  34 ++++--
>   t/t7063-status-untracked-cache.sh | 193 +++++++++++++++++-------------
>   t/t7519-status-fsmonitor.sh       |   8 +-
>   3 files changed, 135 insertions(+), 100 deletions(-)
> 
> diff --git a/dir.c b/dir.c
> index 3474e67e8f3c..9f7c8debeab3 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -2760,12 +2760,29 @@ static struct untracked_cache_dir *validate_untracked_cache(struct dir_struct *d
>   	return root;
>   }
>   
> +static void trace2_read_directory_statistics(struct dir_struct *dir,
> +					     struct repository *repo)
> +{
> +	if (!dir->untracked)
> +		return;

Is there value to also printing the path?
The existing `trace_performance_leave()` calls were, but
I'm familiar enough with this code to say if the output
wasn't always something like ".".

> +	trace2_data_intmax("read_directory", repo,
> +			   "node-creation", dir->untracked->dir_created);
> +	trace2_data_intmax("read_directory", repo,
> +			   "gitignore-invalidation",
> +			   dir->untracked->gitignore_invalidated);
> +	trace2_data_intmax("read_directory", repo,
> +			   "directory-invalidation",
> +			   dir->untracked->dir_invalidated);
> +	trace2_data_intmax("read_directory", repo,
> +			   "opendir", dir->untracked->dir_opened);
> +}
> +

The existing code was quite tangled and I think this helps
make things more clear.


>   int read_directory(struct dir_struct *dir, struct index_state *istate,
>   		   const char *path, int len, const struct pathspec *pathspec)
>   {
>   	struct untracked_cache_dir *untracked;
>   
> -	trace_performance_enter();
> +	trace2_region_enter("dir", "read_directory", istate->repo);
>   
>   	if (has_symlink_leading_path(path, len)) {
>   		trace_performance_leave("read directory %.*s", len, path);

This `trace_performance_leave()` inside the `if` needs to be
converted too.


> @@ -2784,23 +2801,13 @@ int read_directory(struct dir_struct *dir, struct index_state *istate,
>   	QSORT(dir->entries, dir->nr, cmp_dir_entry);
>   	QSORT(dir->ignored, dir->ignored_nr, cmp_dir_entry);
>   
> -	trace_performance_leave("read directory %.*s", len, path);
> +	trace2_region_leave("dir", "read_directory", istate->repo);

Can we put the call to `trace2_read_directory_statistics()` before
the above `trace2_region_leave()` call?   Then those stats will
appear indented between the begin- and end-region events in the output.

That way, the following `if (dir-untracked) {...}` is only
concerned with the untracked cache and/or freeing that data.

>   	if (dir->untracked) {
>   		static int force_untracked_cache = -1;
> -		static struct trace_key trace_untracked_stats = TRACE_KEY_INIT(UNTRACKED_STATS);
>   
>   		if (force_untracked_cache < 0)
>   			force_untracked_cache =
>   				git_env_bool("GIT_FORCE_UNTRACKED_CACHE", 0);
> -		trace_printf_key(&trace_untracked_stats,
> -				 "node creation: %u\n"
> -				 "gitignore invalidation: %u\n"
> -				 "directory invalidation: %u\n"
> -				 "opendir: %u\n",
> -				 dir->untracked->dir_created,
> -				 dir->untracked->gitignore_invalidated,
> -				 dir->untracked->dir_invalidated,
> -				 dir->untracked->dir_opened);
>   		if (force_untracked_cache &&
>   			dir->untracked == istate->untracked &&
>   		    (dir->untracked->dir_opened ||
> @@ -2811,6 +2818,9 @@ int read_directory(struct dir_struct *dir, struct index_state *istate,
>   			FREE_AND_NULL(dir->untracked);
>   		}
>   	}
> +
> +	if (trace2_is_enabled())
> +		trace2_read_directory_statistics(dir, istate->repo);

Also, I think it'd be ok to move the `trace2_is_enabled()` call
inside the function.  Since we're also testing `!dir->untracked`
inside the function.

The more that I look at the before and after versions, the
more I think the `trace2_read_directory_statistics()` call
should be up before the `trace2_region_leave()`.  Here at the
bottom of the function, we may have already freed `dir->untracked`.
I'm not familiar enough with this code to know if that is a
good or bad thing.


>   	return dir->nr;
>   }
>   
...


Thanks,
Jeff