From: Zach Riggle <zachriggle@gmail.com>
Date: Tue, 07 Jul 2020 21:25:01 GMT
Subject: git grep --threads 12 --textconv is effectively single-threaded
Message-ID: <CAMP9c5nUteg_HouuYJZtq7g4MrSE638mns=HeKhNpNTYgQB4=w@mail.gmail.com>

It looks like the bit of code that is responsible for performing
textconv conversions is single-threaded, even if git-grep is provided
a number of threads to use.

This greatly limits the usability of textconv filters for grep
expressions over a large number of files.

Note the difference in total CPU usage in the following expressions:

$ git grep --threads 12 -e foobar --and -e fizzbuzz &> /dev/null
0.24s user 0.28s system 710% cpu 0.073 total

$ git grep --threads 12 -e foobar --and -e fizzbuzz --textconv &> /dev/null
0.90s user 1.75s system 110% cpu 2.390 total

$ git version
git version 2.27.0

Zach Riggle