Tags: patch


In rgrep, check matching files before excluding files

There are a lot of excluding globs, and checking them all is expensive.
The files glob (i.e. the glob for files we actually want) is usually
just one or two entries, so it's quite fast to check.

If find checks the files glob first and then the excluding glob, it has
to do much less checking (since the files glob will substantially narrow
down the set of files on its own), and find performance is much better.

In my benchmarking, this takes (rgrep "foo" "*.el" "~/src/emacs/trunk/")
from ~410ms to ~130ms.

When the files glob is "* .*", there's no benefit from this change,
since we still have to check every excluding glob anyway.  But there's
also no cost.

* lisp/progmodes/grep.el (rgrep-default-command): Move the
excluded files glob to part of the "files" argument.

In GNU Emacs 29.2.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.15.12, Xaw scroll bars) of 2024-05-20 built on
 igm-qws-u22796a
Repository revision: 734740051bd377d24899d08d00ec8e1bb8e00e00
Repository branch: emacs-29
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Rocky Linux 8.9 (Green Obsidian)

Configured using:
 'configure -C --with-x-toolkit=lucid --with-gif=ifavailable
 --with-native-compilation=aot'