Date: Wed, 4 Jun 1997 00:31:54 -0700 (MST) From: Richard Straka <straka@inficad.com> To: current@freebsd.org Subject: sio driver performance Message-ID: <Pine.BSI.3.95.970604001520.15234B-100000@user2.inficad.com>
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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. Richard Straka straka@inficad.com
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