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 file
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'
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 performance
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 pe
>
> 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 vari
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 char
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 cod
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). B
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
> rea
>
>
> 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 h
11 matches
Mail list logo
