Re: [PATCH 3/4] repack: add --sparse and pass to pack-objects

["Dr N.W. Filardo" <nwf20@cam.ac.uk>]

On 2019-03-12 13:47, Derrick Stolee wrote:
> On 3/12/2019 9:18 AM, Nathaniel Filardo wrote:
>> The sparse connectivity algorithm saves a whole lot of time when there
>> are UNINTERESTING trees around.
> 
> Interesting! Do you have some performance numbers to include with
> this statement?

Not UNINTERESTING? ;)

Not directly, no, but the performance numbers reported for the next 
patch in
the series hinge on using sparse reachability.  It seemed like a good 
idea to
expose this knob through repack even if one isn't going to use the
--assume-pack-keep-transitive flag introduced in the next patch.

>> @@ -48,6 +49,10 @@ static int repack_config(const char *var, const 
>> char *value, void *cb)
>>  		use_delta_islands = git_config_bool(var, value);
>>  		return 0;
>>  	}
>> +	if (!strcmp(var, "pack.usesparse")) {
>> +		sparse = git_config_bool(var, value);
>> +		return 0;
>> +	}
> 
> This part is not handled inside of `pack-objects`. Since you are not
> sending '--no-sparse' when the variable 'sparse' is zero, the config
> setting will automatically be picked up by the pack-objects builtin.

OK, I will drop this hunk.

> Now, a question of whether you _should_ allow the '--no-sparse' option
> in the 'repack' command, and send it along to the inner command (when
> it is present) is another question.

I'm inclined to say yes, but am open to suggestions. :)

>> @@ -366,6 +374,8 @@ int cmd_repack(int argc, const char **argv, const 
>> char *prefix)
>>  	argv_array_push(&cmd.args, "--all");
>>  	argv_array_push(&cmd.args, "--reflog");
>>  	argv_array_push(&cmd.args, "--indexed-objects");
>> +	if (sparse)
>> +		argv_array_push(&cmd.args, "--sparse");
>>  	if (repository_format_partial_clone)
>>  		argv_array_push(&cmd.args, "--exclude-promisor-objects");
>>  	if (write_bitmaps)
>> 
> 
> How about a test with this new option? You can probably just add to
> t5322-pack-objects-sparse.sh.

Can do.

Cheers,
--nwf;