Re: grep vs git grep performance?

From: SZEDER Gábor <szeder.dev@gmail.com>
Date: Oct 26, 2017, 16:13 UTC
Message-ID: <20171026161354.23037-1-szeder.dev@gmail.com>
In-Reply-To: <1509030170.10651.59.camel@perches.com>

Show 18 quoted lines

> Comparing a cache warm git grep vs command line grep
> shows significant differences in cpu & wall clock.
> 
> Any ideas how to improve this?
> 
> $ time git grep "\bseq_.*%p\W" | wc -l
> 112
> 
> real	0m4.271s
> user	0m15.520s
> sys	0m0.395s
> 
> $ time grep -r --include=*.[ch] "\bseq_.*%p\W" * | wc -l
> 112
> 
> real	0m1.164s
> user	0m0.847s
> sys	0m0.314s

Note that this "regular" grep is limited to *.c and *.h files, while the above git grep invocation isn't and has to look at all tracked files. How does

  git grep "\bseq_.*%p\W" "*.[ch]"

fare?