Re: [PATCH] speed: reuse char instead of recreation in loop

[Thomas Spura <tomspur@fedoraproject.org>]

Am Mon, 25 May 2009 22:16:02 +0200 schrieb Björn Steinbrink:

> On 2009.05.25 19:44:10 +0000, Thomas Spura wrote:
>> Move a char and a char * outside of a for loop for speed improvements
>> 
>> Signed-off-by: Thomas Spura <tomspur@fedoraproject.org> ---
>> Comments?
>> 
>>  transport.c |    7 +++----
>>  1 files changed, 3 insertions(+), 4 deletions(-)
>> 
>> diff --git a/transport.c b/transport.c index 17891d5..e350937 100644
>> --- a/transport.c
>> +++ b/transport.c
>> @@ -263,11 +263,10 @@ static int write_refs_to_temp_dir(struct strbuf
>> *temp_dir,
>>  		int refspec_nr, const char **refspec)
>>  {
>>  	int i;
>> +	unsigned char sha1[20];
>> +	char *ref;
>>  
>>  	for (i = 0; i < refspec_nr; i++) {
>> -		unsigned char sha1[20];
>> -		char *ref;
>> -
> 
> I doubt that this makes any difference at all.

With ints, the loop costs about 40% of speed. Without recreation, it 
should be always faster.

> 
>>  		if (dwim_ref(refspec[i], strlen(refspec[i]), sha1, &ref) !
>> = 1)
>>  			return error("Could not get ref %s", refspec[i]);
>>  
>> @@ -275,8 +274,8 @@ static int write_refs_to_temp_dir(struct strbuf
>> *temp_dir,
>>  			free(ref);
>>  			return -1;
>>  		}
>> -		free(ref);
>>  	}
>> +	free(ref);
> 
> And this now leaks memory.

Hmm, I don't see it atm. Where do you mean?