GNU bug report logs - #34343
[PATCH] Make project--find-regexp-in-files work with remote files

Previous Next

Full log

View this message in rfc822 format

From: Michael Albinus <michael.albinus <at> gmx.de>
To: Dmitry Gutov <dgutov <at> yandex.ru>
Cc: 34343 <at> debbugs.gnu.org, Felicián Németh <felician.nemeth <at> gmail.com>
Subject: bug#34343: [PATCH] Make project--find-regexp-in-files work with remote files
Date: Wed, 01 Jan 2020 13:29:52 +0100

Dmitry Gutov <dgutov <at> yandex.ru> writes:

>> Not always. But even if it calls expand-file-name, this doesn't mean
>> always that a remote command is fired. This is what is expensive.
>
> That depends on our performance goals. As described in
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=34343#29, when called on
> a lot of files, it can be fairly expensive even when offline.
>
> But eliminating remote calls will be a win, for sure.

I've played a little bit with this. Even if there is no remote file name
involved, file-local-name is slow due to the file-remote-p call and the
file name handler mechanery. See:

--8<---------------cut here---------------start------------->8---
(benchmark-run-compiled
    nil
  (dotimes (i 1000000) (format "/tmp/%d" i)))

=> (1.720033035 16 1.2495203040000007)
--8<---------------cut here---------------end--------------->8---

This is my initial example. Evall'ing `format' 1.000.000 times.

--8<---------------cut here---------------start------------->8---
(benchmark-run-compiled
    nil
  (dotimes (i 1000000) (file-local-name (format "/tmp/%d" i))))

=> (5.072258441 16 1.2559830709999957)
--8<---------------cut here---------------end--------------->8---

Although still a local file name, the elapsed time is about three times
as large in the initial example.

--8<---------------cut here---------------start------------->8---

(benchmark-run-compiled
    nil
  (let ((remote (file-remote-p  "/tmp")))
    (dotimes (i 1000000)
      (if remote
	  (file-local-name (format "%s/%d" remote i))
	(format "%s/%d" remote i)))))

=> (1.831333636 16 1.2604051830000103)
--8<---------------cut here---------------end--------------->8---

Refactoring the code, and applying `file-local-name' just to the cases
where it is needed, shows an elapsed time similar to the initial one.

Best regards, Michael.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.