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Date: Wed, 4 Jun 1997 00:43:54 -0700 (MST)
From: Richard Straka <straka@inficad.com>
To: current@freebsd.org
Subject: Re: sio driver performance
In-Reply-To: <Pine.BSI.3.95.970604001520.15234B-100000@user2.inficad.com>
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On Wed, 4 Jun 1997, Richard Straka wrote:

> I have 2 16550A UARTS in a 486DX-33.  During probing, the sio
> driver properly identifies both ports as 16550A's.
> 
> When sending sustained 115200 baud data from this machine, systat
> (with vmstat option) indicates an interrupt rate of about 720/sec
> with about 2% of the processor servicing interrupts.
> When receiving sustained 115200 baud data, an interrupt rate of 
> over 26,000/sec is indicated with about 15% of the processor going 
> to service interrupts.
> 
> It appears as though the fifo is not working for the receive. In an
> attempt to exhonerate the hardware, I swapped in another 16550 card
> I had laying around and got the similar results.
> 
> Any help on this issue would be greatly appreciated. 
>

I neglected to mention that I am running 2.2.1-RELEASE on the 486DX-33.

 
 Richard Straka
 straka@inficad.com