Subject: Re: RFH: serial port benchmarking
To: Garrett D'Amore <email@example.com>
From: Garrett D'Amore <firstname.lastname@example.org>
Date: 06/23/2006 08:36:43
Daniel Carosone wrote:
> On Tue, Jun 20, 2006 at 11:55:27AM -0700, Garrett D'Amore wrote:
>> I'm looking for someone who can help benchmark UART performance to
>> compare gdamore-uart and -current. I suspect that the differences will
>> be small, but I've been asked to provide some more concrete numbers,
>> particularly of interest is i386 hardware, for which I do not have ready
> I did some archeology, and dug up some old machines. I have something
> that I think is an 8Mb 33Mhz 486, and that still seems to power on and
> POST get to the PRESS F1 TO CONTINUE prompt. I'm not going to get
> past this for a while, because it has a large-style AT DIN keyboard
> plug, and I seem to have nothing functional to plug into it now.
> It probably still has some ancient NetBSD, perhaps 0.9-ish era, on the
> 2x200Mb SCSI disks that seem to still both spin up. I hope so, that
> will make the problem of getting code onto it easier.
Thanks. I probably can scrounge a large style->small style keyboard
adapter. What I don't know is whether it is for plugging a small
keyboard in a large hole or vice versa. I'll check and get back to you.
>> (I also don't know how best to collect such performance data on
>> i386 -- are there processor performance counters that can be used?)
> My plan would be to set up some back-to-back serial transfers with a
> modern machine, and crank up the serial speed until it starts to spew
> about silo overflows. If the current and branch kernels start failing
> at different speeds, i'd call the effect noticable. Suggestions for
> other tests that I can perform without too much effort welcome.
That sounds like a good idea to me.
>> Also, if anyone has com(4) ports that are marginal at performance, it
>> would be great to test them to verify that I haven't made things any
>> worse. :-)
> I found a whole lot of ISA serial cards, at least one with big chunky
> 83450's on, probably others. It's not impossible that I have a HAYESP
> around somewhere, too.
Cool. Thanks for the help, btw!
Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134 Fax: 951 325-2191