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Re: request for review: Doing direct file I/O in Emacs Lisp
From: |
Richard Stallman |
Subject: |
Re: request for review: Doing direct file I/O in Emacs Lisp |
Date: |
Sat, 15 May 2004 14:33:53 -0400 |
Below are the results of comparing write-region to the file-handle
API. This test used Eshell's builtin cat to write 21MB to another
file.
~74s save-buffer (the current method)
~82s file-handle-write
~250s write-region [with call to `message' disabled]
~318s write-region
It is interesting that write-region is by far the most inefficient,
and that my file-handle API is not the fastest method.
Since save-buffer calls write-region, both the fastest and the slowest
method use write-region. What is the difference between these two
methods?
I wonder if it has to do with whether a coding system is being
used, or whether a coding system is being detected automatically.
However, the real slowdown is with start-process, as others mentioned.
Here are the times for doing the same cat, but using the system's cat:
Sorry, I do not understand what that means.
~952s file-handle-write
...s save-buffer (the current method)
I can't understand what alternatives you have compared.
Could you please explain them more concretely?
start-process takes a certain amount of time, but it should be a fixed
amount, and less than a second. How many times did you start a
process here?
- Re: request for review: Doing direct file I/O in Emacs Lisp, (continued)
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/10
- Re: request for review: Doing direct file I/O in Emacs Lisp, John Wiegley, 2004/05/11
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/12
- Re: request for review: Doing direct file I/O in Emacs Lisp, Kai Grossjohann, 2004/05/13
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/14
- Re: request for review: Doing direct file I/O in Emacs Lisp, Kai Grossjohann, 2004/05/14
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/15
- Re: request for review: Doing direct file I/O in Emacs Lisp, Kai Grossjohann, 2004/05/15
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/16
- Re: request for review: Doing direct file I/O in Emacs Lisp, John Wiegley, 2004/05/14
- Re: request for review: Doing direct file I/O in Emacs Lisp,
Richard Stallman <=
- Re: request for review: Doing direct file I/O in Emacs Lisp, John Wiegley, 2004/05/15
- Re: request for review: Doing direct file I/O in Emacs Lisp, David Kastrup, 2004/05/15
- Re: request for review: Doing direct file I/O in Emacs Lisp, Eli Zaretskii, 2004/05/16
- Re: request for review: Doing direct file I/O in Emacs Lisp, David Kastrup, 2004/05/16
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/17
- Re: request for review: Doing direct file I/O in Emacs Lisp, John Wiegley, 2004/05/13
- Re: request for review: Doing direct file I/O in Emacs Lisp, Richard Stallman, 2004/05/14