Date: Sat, 8 Feb 1997 06:00:19 +1100 From: Bruce Evans <bde@zeta.org.au> To: bmcgover@cisco.com, dg@root.com, support@cyclades.com Cc: hackers@freebsd.org, waz@cyclades.com Subject: Re: Flow control on Cyclades boards??? Message-ID: <199702071900.GAA13110@godzilla.zeta.org.au>
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>Ok. I now have the boards up and running between machines, but I'm having a >problem with silo overflows almost constantly on all the currently running >ports. I'm using pppd (options listed below) to set up a number of ppp >sessions between two pentium pro 200s. > >I originally tried to run 32 of them at 115200. It failed miserably. I then >dropped back to 16 at 115200. Then to 16 at 57600. Still got silo >errors constantly. The PCI Cyclades driver doesn't support "fast" interrupt handlers yet (because the PCI interrupt dispatcher doesn't), so at 115200 bps, each fully active port will get N fifo full's worth of silo overflows (12 * N characters) whenever the kernel disables tty interrupts for N milliseconds. The kernel sometimes disables tty interrupts for several milliseconds. This can't be fixed using flow control or any other configuration option. Bruce
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