On Fri, 9 Apr 1999, Hal Murray wrote:

> 
> > TCP streams via FTP seem FUBAR.  In pretty much any combination that we've
> > tried, an alpha talking to an alpha gives about 50-100KBytes/second
> > throughput - about 1/100 of what it should.  Same HW ifconfig'd to 10baseT
> > gives 1MB/sec, i.e. full 10baseT throughput.
> 
> > The same x86 when talking to an alpha on the same 100baseT switch 
> > gives 6.5 MB/second.
> 
> I think the "switch" in there is the critical piece of info. 
> 
> I'm pretty sure there is a bug in the Tulip driver such that 100 
> megabits at full duplex doesn't work.  100/half works fine for me 
> (on Miatas). 

I'm trying to describe a problem that exists, switch or no switch, hub or
no hub.  I can direct wire two alphas with de0 interfaces together using a
crossover TP cable that still shows the problem.  As far as I know, you
have to specify ifconfig de0 media full-duplex in order to get full-duplex
operation - is this correct?

I believe ifconfig de0 will show it is in full-duplex mode if that was
selected.  None of the interfaces I am talking about have this enabled.

> I've seen the same problems on Miata.  We've also seen it on Intel 
> boxes running FreeBSD which uses the same driver. 

I agree, which is why I'm not running full-duplex on any of my intel or
alpha boxes.

> I haven't looked at the driver.  One of our guys spent several days 
> trying to track this down (on FreeBSD/Intel).  He couldn't find anything 
> wrong. 
> 
> I suggest you try half duplex. 

As far as I know, I've only run full-duplex a long time ago for sake of
amusement to see if it gave higher throughput.  I don't run it as part of
any of my normal machines setup.

Paul

+------------------------------------------------------+
| Paul Anderson           Public Data Queries, Inc.    |
| pha@pdq.com             734-213-4964(W) 994-3734(H)  |
+------------------------------------------------------+