Re: grep vs git grep performance?

From: Joe Perches <joe@perches.com>
Date: Oct 26, 2017, 15:55 UTC
Message-ID: <1509033321.11245.3.camel@perches.com>
In-Reply-To: <CAFQ2z_P9bpw+Pc2DhJTCB8dxj-5JAKLE=nyvToGuiRA8wV66Wg@mail.gmail.com>

On Thu, 2017-10-26 at 17:11 +0200, Han-Wen Nienhuys wrote:

Show 7 quoted lines

> On Thu, Oct 26, 2017 at 5:02 PM, Joe Perches <joe@perches.com> 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