From: Richard Stallman <rms@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: request for review: Doing direct file I/O in Emacs Lisp
Date: Mon, 17 May 2004 07:04:14 -0400 [thread overview]
Message-ID: <E1BPfuo-0005oM-En@fencepost.gnu.org> (raw)
In-Reply-To: <m2zn89tlsp.fsf@gnu.org> (message from John Wiegley on Sat, 15 May 2004 14:36:38 -0700)
Hmm.. that IS curious. In the save-buffer case, I call
insert-and-inherit in a temp buffer thousands of times, then one call
to save-buffer. In the write-region case, I am calling write-region
thousands of times. I think the difference is the constant filesystem
access in the latter case.
Now that I see what the last alternative consists of, I am sure that
is true.
You could try calling write-region using a temporary buffer
after making sure that buffer-file-coding-system is set.
That might be somewhat faster than using save-buffer.
> I can't understand what alternatives you have compared.
> Could you please explain them more concretely?
If I start a process with start-process (/usr/bin/cat) and redirect
its output to a file, it is far slower than if I simply output the
same data to a file (eshell/cat) -- even though the resulting "output"
in both cases is the same. Why is receiving output via a process
sentinel so slow?
As far as I can see, neither of the two cases you described involves
receiving output from a subprocesses at all, so neither one involves
the sentinel. I suspect that the former case is slow because sending
input to the subprocess takes time.
Someone else suggested process switching overhead.may be a big
factor in that. It sounds plausible.
next prev parent reply other threads:[~2004-05-17 11:04 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-10 5:59 request for review: Doing direct file I/O in Emacs Lisp John Wiegley
2004-05-10 6:52 ` Kim F. Storm
2004-05-10 8:27 ` David Kastrup
2004-05-10 14:21 ` Stefan Monnier
2004-05-10 15:59 ` David Kastrup
2004-05-10 16:36 ` Stefan Monnier
2004-05-10 17:00 ` David Kastrup
2004-05-10 17:22 ` Stefan Monnier
2004-05-11 9:23 ` John Wiegley
2004-05-11 10:22 ` David Kastrup
2004-05-10 9:38 ` Andreas Schwab
2004-05-10 11:29 ` Eli Zaretskii
2004-05-10 11:23 ` Andreas Schwab
2004-05-10 15:04 ` Eli Zaretskii
2004-05-10 14:19 ` Stefan Monnier
2004-05-10 17:46 ` Oliver Scholz
2004-05-10 18:21 ` Stefan Monnier
2004-05-10 22:40 ` Oliver Scholz
2004-05-11 12:22 ` Richard Stallman
2004-05-10 17:54 ` Richard Stallman
2004-05-11 9:20 ` John Wiegley
2004-05-12 19:41 ` Richard Stallman
2004-05-13 7:59 ` Kai Grossjohann
2004-05-14 9:21 ` Richard Stallman
2004-05-14 10:42 ` Kai Grossjohann
2004-05-15 8:53 ` Richard Stallman
2004-05-15 16:27 ` Kai Grossjohann
2004-05-16 13:20 ` Richard Stallman
2004-05-14 21:43 ` John Wiegley
2004-05-15 18:33 ` Richard Stallman
2004-05-15 21:36 ` John Wiegley
2004-05-15 22:13 ` David Kastrup
2004-05-16 6:41 ` Eli Zaretskii
2004-05-16 17:46 ` David Kastrup
2004-05-17 11:04 ` Richard Stallman [this message]
2004-05-13 22:50 ` John Wiegley
2004-05-14 21:02 ` Richard Stallman
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