Re: [PATCH 2/5] odb/source-files: fix performance when streaming objects with alternates

[Justin Tobler <jltobler@gmail.com>]

On 26/10/13 09:36AM, Patrick Steinhardt wrote:
> This patch is essentially the equivalent to the preceding patch, but for
> streaming objects instead of just reading them directly.
> 
> Exercising performance is a bit more complicated here as streaming only
> really kicks in for large objects. Furthermore, I expect that the impact
> is not as big as with the last commit, either, because for large objects
> the time to stat the file will probably be dwarfed by the time it takes
> to read the object itself.
> 
> But even though this is probably not as impactful, it makes sense anyway
> to do this change to align behaviour across both of these functions.

I agree that this change is probably not as impactful, but unifying the
behavior makes sense to me and doesn't really have any draw backs. I
think this is a good change.

> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  odb/source-files.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/odb/source-files.c b/odb/source-files.c
> index 9268f5aa9a..54235821d5 100644
> --- a/odb/source-files.c
> +++ b/odb/source-files.c
> @@ -462,8 +462,10 @@ static int odb_source_files_read_object_stream(struct odb_stream **out,
>  	struct odb_source_files *files = odb_source_files_downcast(source);
>  
>  	for (struct odb_files_dir *dir = files->dirs; dir; dir = dir->next)
> -		if (!odb_source_read_object_stream(out, &dir->packed->base, oid) ||
> -		    !odb_source_read_object_stream(out, &dir->loose->base, oid))
> +		if (!odb_source_read_object_stream(out, &dir->packed->base, oid))
> +			return 0;
> +	for (struct odb_files_dir *dir = files->dirs; dir; dir = dir->next)
> +		if (!odb_source_read_object_stream(out, &dir->loose->base, oid))

Just like the last patch, each source looks through its packfiles first
before looking at loose objects. Looks good.

-Justin