Subject: Re: [PATCH] lookup_object: split up displacement penalty for hash collisions

From: Thomas Rast <[email-masked]>
Date: Fri, 16 Aug 2013 11:26:28 +0200

Thomas Rast <[email-masked]> writes:

> Stefan Beller <[email-masked]> writes:
>
>> However please do check if this patch brings the promised performance
>> on your own, as you're likely using different hardware and another
>> software setup. Feel free to share your performance differences.
>
> I get this on an i7-M620 laptop from t/perf/p0001-rev-list.sh:
>
>   Test                               HEAD                next                    
>   -------------------------------------------------------------------------------
>   0001.1: rev-list --all             6.29(6.03+0.22)     6.33(6.06+0.24) +0.6%   
>   0001.2: rev-list --all --objects   53.22(52.48+0.54)   54.90(54.15+0.55) +3.2%*
>   -------------------------------------------------------------------------------
>   Significance hints:  '.' 0.1  '*' 0.05  '**' 0.01  '***' 0.001
[...]
> I trust the laptop numbers less because it has far more thermal (and
> thus throttling) issues, but the runs do show a significant difference,
> though less than you claimed.

Well, as I feared... another run on the same laptop:

Test                               HEAD                next                                            
------------------------------------------------------------------------------
0001.1: rev-list --all             6.41(6.14+0.24)     6.36(6.10+0.23) -0.9%* 
0001.2: rev-list --all --objects   54.60(53.84+0.55)   54.23(53.50+0.53) -0.7%
------------------------------------------------------------------------------
Significance hints:  '.' 0.1  '*' 0.05  '**' 0.01  '***' 0.001

-- 
Thomas Rast
trast@{inf,student}.ethz.ch