On 12/11/2007, Randall Hyde [EMAIL PROTECTED] wrote:
At this point I'm not sure why FreeBSD's API call is so slow (btw, it's not
the system call that's responsible, if I make several additional API calls
on each read, e.g., doing lseeks, this has only a marginal impact on
performance). But
On Sun, Nov 11, 2007 at 09:52:21AM -0800, Randall Hyde wrote:
why C's code was so much faster, I dug into the source code and discovered
that open/read/write/etc. use *buffered* I/O (which explains why dd
performs so well).
open/read/write/etc. do _not_ do any buffering in userland. This is
Randall Hyde wrote:
Hi All,
I recently ported my HLA (High Level Assembler) compiler to FreeBSD and,
along with it, the HLA Standard Library. I have a performance-related
question concerning file I/O.
It appears that character-at-a-time file I/O is *exceptionally* slow. Yes, I
realize
Hello Randy,
First, let me out myself as a fan of yours. It was your book that got me
started on ASM and taught me a lot about computers and logic, plus it
provided some entertainment and mental sustenance in pretty boring
times, so thanks!
Now, as for your problem: I think I have to
Hi All,
Well, I've done some sleuthing and discovered some issues.
First, the dd command produced approximately the same results everyone
else was getting. So I rewrote a version of my test code in C using the
stdlib read call and it had really great performance. Not understanding
why C's code
On Fri, Nov 09, 2007 at 08:36:32AM -0800, Randall Hyde wrote:
To answer a different question in the thread, I'm pretty sure I'm making
only one FreeBSD call per byte, at least in one of the cases I posted.
How about using ktrace or similar to confirm this.
I wonder if I'm only getting one
On Thu, 8 Nov 2007 16:52:38 -0600, Dan Nelson wrote:
In the last episode (Nov 08), Randall Hyde said:
It appears that character-at-a-time file I/O is *exceptionally* slow.
Yes, I realize that when processing large files I really ought to be
doing block/buffered I/O to get the best
You should also carefully do an strace or similar on
Windows and Linux as well. You may find that you're
doing a system call per byte on FreeBSD but not on
those other systems.
Certainly this might be possible under Windows, as I have no idea what
happens once I link in one of the various
Hi All,
I recently ported my HLA (High Level Assembler) compiler to FreeBSD and,
along with it, the HLA Standard Library. I have a performance-related
question concerning file I/O.
It appears that character-at-a-time file I/O is *exceptionally* slow. Yes, I
realize that when processing large
In the last episode (Nov 08), Randall Hyde said:
It appears that character-at-a-time file I/O is *exceptionally* slow.
Yes, I realize that when processing large files I really ought to be
doing block/buffered I/O to get the best performance, but for certain
library routines I've written it's
Dan Nelson wrote:
In the last episode (Nov 08), Randall Hyde said:
It appears that character-at-a-time file I/O is *exceptionally* slow.
... reasonable, though not stellar, performance under
Windows and Linux. However, with the port to FreeBSD I'm seeing a
three-orders-of-magnitude
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