From: David L Brown <dbrown@ted.vigra.com>
Subject: Re: CRC in Ada?
Date: 1997/03/04
Date: 1997-03-04T00:00:00+00:00 [thread overview]
Message-ID: <oslo83b70l.fsf@ted.vigra.com> (raw)
In-Reply-To: 1997Mar2.220652@nova.wright.edu
garriga@logica.com (Stephen Garriga) writes:
> _IF_ you are doing the CRC on a file (as I was), I would advise you
> to consider performance. I found (exactly the same algorithm)
> implemented in C took an order of magnitude seconds less to execute
> than the Ada equivalent.
Well, I tried this. I wrote a small program to read files and compute
CRC16's on them. What I found was disheartening. The CRC code didn't
take very long. However, the Stream_IO read of the data was very
slow. I traced it down to doing a call to the C read function for
each byte.
I'm using GNAT 3.09 on Linux (pentium). Is there anything about the
specification for Stream_IO (or Text_IO for that matter) that is
causing the GNAT runtime to turn off buffering. This is a real
performance hit, and I have had to revert to calling the C routines
directly when streams would be adequate, if they just weren't so
inefficient.
Dave
next prev parent reply other threads:[~1997-03-04 0:00 UTC|newest]
Thread overview: 143+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-03-02 0:00 CRC in Ada? Dr. John B. Matthews
1997-03-03 0:00 ` David Brown
1997-03-03 0:00 ` Tom Moran
1997-03-04 0:00 ` David L Brown [this message]
1997-03-04 0:00 ` Robert Dewar
1997-03-05 0:00 ` Stephen Garriga
1997-03-05 0:00 ` Larry Kilgallen
1997-03-05 0:00 ` Robert A Duff
1997-03-05 0:00 ` Larry Kilgallen
1997-03-06 0:00 ` Fergus Henderson
1997-03-06 0:00 ` Larry Kilgallen
1997-03-06 0:00 ` Robert A Duff
1997-03-07 0:00 ` Robert Dewar
1997-03-07 0:00 ` Larry Kilgallen
1997-03-07 0:00 ` Robert A Duff
1997-03-07 0:00 ` Tom Moran
[not found] ` <1997Mar7.202252.1@eisner>
1997-03-08 0:00 ` Robert Dewar
1997-03-09 0:00 ` Geert Bosch
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Mats Weber
1997-03-12 0:00 ` Robert Dewar
1997-03-10 0:00 ` Dr. John B. Matthews
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Tom Moran
1997-03-12 0:00 ` Robert Dewar
1997-03-10 0:00 ` Jim Balter
1997-03-10 0:00 ` Jim Balter
1997-03-06 0:00 ` Robert Dewar
1997-03-06 0:00 ` Robert A Duff
1997-03-06 0:00 ` Larry Kilgallen
1997-03-06 0:00 ` Robert Dewar
1997-03-06 0:00 ` Robert Dewar
1997-03-09 0:00 ` Dr. John B. Matthews
1997-03-06 0:00 ` Robert Dewar
1997-03-10 0:00 ` Tarjei Jensen
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Graham Hughes
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Graham Hughes
1997-03-12 0:00 ` Robert Dewar
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` David Brown
1997-03-12 0:00 ` Robert Dewar
1997-03-11 0:00 ` Mark & Zurima McKinney
1997-03-12 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Robert I. Eachus
1997-03-13 0:00 ` Jon S Anthony
1997-03-13 0:00 ` Robert Dewar
1997-03-14 0:00 ` Jim Balter
1997-03-14 0:00 ` Jon S Anthony
1997-03-15 0:00 ` Robert Dewar
1997-03-15 0:00 ` Dr. John B. Matthews
1997-03-17 0:00 ` Jon S Anthony
1997-03-06 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Robert Dewar
1997-03-08 0:00 ` Robert A Duff
1997-03-10 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-14 0:00 ` Richard A. O'Keefe
1997-03-14 0:00 ` Jim Balter
1997-03-06 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-06 0:00 ` Larry Kilgallen
1997-03-09 0:00 ` Robert Dewar
1997-03-06 0:00 ` Graham Hughes
1997-03-06 0:00 ` Robert Dewar
1997-03-07 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` Robert Dewar
1997-03-08 0:00 ` Fergus Henderson
1997-03-10 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-11 0:00 ` Jim Balter
1997-03-12 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-14 0:00 ` Samuel Mize
1997-03-07 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-07 0:00 ` David Brown
1997-03-10 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-10 0:00 ` Robert Dewar
1997-03-10 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-11 0:00 ` Jim Balter
1997-03-11 0:00 ` Robert Dewar
1997-03-12 0:00 ` Jim Balter
1997-03-11 0:00 ` Fergus Henderson
1997-03-10 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-11 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Jim Balter
1997-03-12 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-12 0:00 ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-03-04 0:00 ` Jon S Anthony
1997-03-05 0:00 ` Robert Dewar
1997-03-04 0:00 ` Stephen Garriga
1997-03-04 0:00 ` Robert Dewar
1997-03-05 0:00 ` Stephen Garriga
1997-03-15 0:00 ` Michael & Amy Hartsough
1997-03-16 0:00 ` Robert Dewar
1997-03-16 0:00 ` Michael & Amy Hartsough
1997-03-16 0:00 ` Robert Dewar
1997-03-18 0:00 ` Michael & Amy Hartsough
1997-03-19 0:00 ` Robert Dewar
1997-03-20 0:00 ` Michael & Amy Hartsough
1997-03-22 0:00 ` Robert Dewar
1997-03-24 0:00 ` Sequential IO on OpenVMS (was: CRC in Ada?) Ken Garlington
1997-03-24 0:00 ` Larry Kilgallen
1997-03-22 0:00 ` CRC in Ada? Mark & Zurima McKinney
1997-03-22 0:00 ` Robert Dewar
1997-03-21 0:00 ` Tom Moran
1997-03-23 0:00 ` Robert Dewar
1997-03-23 0:00 ` Tom Moran
1997-03-24 0:00 ` Portable Code (was: CRC in Ada?) Larry Kilgallen
1997-03-24 0:00 ` CRC in Ada? Robert A Duff
1997-03-24 0:00 ` Larry Kilgallen
1997-03-24 0:00 ` Robert A Duff
1997-03-24 0:00 ` Robert Dewar
1997-03-24 0:00 ` Robert A Duff
1997-03-25 0:00 ` Robert I. Eachus
1997-04-01 0:00 ` David Emery
1997-03-04 0:00 ` Tom Moran
1997-03-04 0:00 ` Stephen Garriga
1997-03-04 0:00 ` Matthew Heaney
1997-03-07 0:00 ` John Apa
1997-03-05 0:00 ` David C. Hoos, Sr.
1997-03-05 0:00 ` Laurent Pautet
1997-03-06 0:00 ` Jon S Anthony
2013-11-14 17:39 ` david
2013-11-14 18:55 ` Adam Beneschan
2013-11-14 19:35 ` tmoran
2013-11-14 20:09 ` Dmitry A. Kazakov
2013-11-14 20:40 ` John B. Matthews
-- strict thread matches above, loose matches on Subject: below --
1997-03-13 0:00 tmoran
1997-03-13 0:00 ` Robert Dewar
1997-03-14 0:00 ` Tom Moran
1997-03-14 0:00 ` Joakim Olsson
1997-03-15 0:00 ` Tom Moran
1997-03-14 0:00 ` Richard A. O'Keefe
1997-03-14 0:00 ` Jon S Anthony
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