Date: p 29 Jun 96 22:10:46 PST From: "Brett Glass" <Brett_Glass@ccgate.infoworld.com> To: Bruce Evans <bde@zeta.org.au>, hdalog@zipnet.net, msmith@atrad.adelaide.edu.au Cc: Kevin_Swanson@BLaCKSMITH.com, chuckr@glue.umd.edu, freebsd-hardware@FreeBSD.org, jparnas@jparnas.cybercom.net Subject: Re: muliport boards - building a PPP dialup server Message-ID: <9605308361.AA836148791@ccgate.infoworld.com>
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> This is actually the weakest point in the sio driver. Polling 16 > ports wastes a lot of time when only a few of them are active, and I > think processing multiple ports per interrupt is relatively rare even > when many of them are active. It's not rare when it MATTERS -- that is, when the FIFOs are filling up. The rest of the time, it merely overcomes a severe deficiency of the PC architecture: the interrupts are edge-triggered, which means that you can't tell whether multiple devices need service unless every one has its own interrupt. --Brett
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