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 performance, but for certain
> > library routines I've written it's been far more convenient to do
> > character-at-a-time I/O rather than deal with all the buffering
> > issues. In the past, while slower, this character-at-a-time paradigm
> > has provided reasonable, though not stellar, performance under
> > Windows and Linux. However, with the port to FreeBSD I'm seeing a
> > three-orders-of-magnitude performance loss. Here's my little test
> > program:
> [...]
> > The "fileio.open" call is basically a bsd.open( "socket.h",
> > bsd.O_RDONLY ); API call. The socket.h file is about 19K long (it's
> > from the FreeBSD include file set). In particular, I would draw your
> > attention to the first two tests that do character-at-a-time I/O. The
> > difference in performance
>
> What timings does
> "dd if=/usr/include/sys/socket.h of=/dev/null ibs=1 obs=64k" report?
> It takes about .4 sec on my non-idle dual pIII-900 system. Try
> truss'ing your program as it runs; maybe the program is doing some
> extra syscalls you aren't aware of?
>
on FreeBSD 6.2-RELEASE, it returns,
dd if=/usr/include/sys/socket.h of=/dev/null ibs=1 obs=64k
18426+0 records in
0+1 records out
18426 bytes transferred in 0.070472 secs (261466 bytes/sec)
--
Regards, /\_/\ "All dogs go to heaven."
dinesh@alphaque.com (0 0) http://www.openmalaysiablog.com/
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