Subject: Re: grep vs git grep performance?

From: Joe Perches <[email-masked]>
Date: Thu, 26 Oct 2017 08:55:21 -0700

On Thu, 2017-10-26 at 17:11 +0200, Han-Wen Nienhuys wrote:
> On Thu, Oct 26, 2017 at 5:02 PM, Joe Perches <[email-masked]> wrote:
> > Comparing a cache warm git grep vs command line grep
> > shows significant differences in cpu & wall clock.
> > 
> > Any ideas how to improve this?
> 
> Is git-grep multithreaded?

Yes, at least according to the documentation

$ git grep --help
[]
       grep.threads
           Number of grep worker threads to use. If unset (or set to 0), 8
           threads are used by default (for now).

> IIRC, grep -r uses multiple threads. (Do
> you have a 4-core machine?)

I have a 2 core machine with hyperthreading

$ cat /proc/cpuinfo
[]
model name	: Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
stepping	: 3
microcode	: 0xba
cpu MHz		: 2400.000
cache size	: 3072 KB
physical id	: 0
siblings	: 4
core id		: 0
cpu cores	: 2