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Re: request for review: Doing direct file I/O in Emacs Lisp
From: |
John Wiegley |
Subject: |
Re: request for review: Doing direct file I/O in Emacs Lisp |
Date: |
Fri, 14 May 2004 14:43:59 -0700 |
User-agent: |
Gnus/5.110002 (No Gnus v0.2) Emacs/21.3.50 (darwin) |
Richard Stallman <address@hidden> writes:
> When eshell sees a redirect from a builtin, I think it would be most
> efficient to produce the output in a buffer and write it with
> write-region into the file.
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. I therefore
retract my earlier proposal.
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:
~952s file-handle-write
...s save-buffer (the current method)
In this case, save-buffer took so long that after 20 minutes Emacs
hung (for some other reason), and I didn't have sufficient patience to
run the test again.
> When it is a matter of a subprocess, what could be useful is a
> feature for start-process to specify files for additional
> descriptors. That would be a completely different feature.
This would be very useful.
John
- 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 <=
- 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, 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