From: dvdeug@my-deja.com
Subject: Re: Optimization Question
Date: Mon, 22 Jan 2001 03:22:44 GMT
Date: 2001-01-22T03:22:44+00:00 [thread overview]
Message-ID: <94g920$k64$1@nnrp1.deja.com> (raw)
In-Reply-To: 94g431$ge3$1@nnrp1.deja.com
In article <94g431$ge3$1@nnrp1.deja.com>,
Robert Dewar <robert_dewar@my-deja.com> wrote:
> In article <94ftfu$b59$1@nnrp1.deja.com>,
> dvdeug@my-deja.com wrote:
>
> <<questions about speeding up code snipped>>
>
> I am *amazed* that this is only ten times slower when the
> I/O is done in such a perfectly gruesome manner (sequential
> I/O instantiated on bytes).
>
> It is elementary that you want to read big chunks of a file
> at a time. What GNAT does is to read the entire source of
> a program in one read statement.
Actually, it's only about 3-5 times slower, after doing more careful
measurements. I think GNU strings might be too wrapped up in the details
of object code to be a good general purpose strings program.
Unfortunately, that "perfectly gruesome manner" is the only one that
jumps out at me. I don't want to use Ada.Text_IO, because I want control
of CR's and LF's. I don't see how to use Sequential I/O on larger
chunks, as I may end up with a piece of file that doesn't fill a chunk.
Direct I/O can't be faster than sequential I/O. And reading a 17GB file
into memory doesn't seem like a good idea.
--
David Starner - dstarner98@aasaa.ofe.org
Sent via Deja.com
http://www.deja.com/
next prev parent reply other threads:[~2001-01-22 3:22 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-01-22 0:05 Optimization Question dvdeug
2001-01-22 1:57 ` Robert Dewar
2001-01-22 3:22 ` dvdeug [this message]
2001-01-22 4:05 ` Robert Dewar
2001-01-22 4:06 ` Robert Dewar
2001-01-22 19:04 ` M. Kotiaho
2001-01-22 20:22 ` dvdeug
2001-01-22 15:24 ` Ted Dennison
2001-01-22 16:12 ` Robert Dewar
2001-01-22 16:48 ` Ted Dennison
2001-01-22 16:15 ` Robert Dewar
2001-01-22 15:26 ` Ted Dennison
2001-01-22 16:17 ` Robert Dewar
2001-01-22 16:59 ` Ted Dennison
2001-01-22 22:01 ` Keith Thompson
2001-01-22 22:52 ` dvdeug
2001-01-23 6:46 ` Keith Thompson
[not found] ` <94ld65$1hs$1@nnrp1.deja.com>
[not found] ` <864ryodb1q.fsf@acm.org>
[not found] ` <3A6F663E.C84B94D8@acm.org>
2001-01-26 16:30 ` Optimization Question -- Follow up on using the stream read (and write) procedures directly Jeff Creem
2001-01-26 21:46 ` Florian Weimer
2001-01-27 19:14 ` Jeff Creem
2001-01-28 0:26 ` Robert Dewar
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