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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!spool.mu.edu!uwm.edu!www.nntp.primenet.com!nntp.primenet.com!ddsw1!news.mcs.net!van-bc!news.mindlink.net!nntp.portal.ca!cynic.portal.ca!not-for-mail From: cjs@cynic.portal.ca (Curt Sampson) Newsgroups: comp.unix.admin,comp.protocols.ppp,comp.unix.questions,comp.unix.bsd.freebsd.misc,comp.unix.bsd.netbsd.misc Subject: Re: Best Unix for SLIP/PPP Server- Best Reliability/Cost? Date: 16 Nov 1996 20:03:21 -0800 Organization: Internet Portal Services, Inc. Lines: 34 Message-ID: <56m2q9$k1c@cynic.portal.ca> References: <56cfhc$h8b@access5.digex.net> <56dl8p$rje@panix2.panix.com> <56igd8$if@anorak.coverform.lan> <56le6q$2c6@panix2.panix.com> NNTP-Posting-Host: cynic.portal.ca Xref: euryale.cc.adfa.oz.au comp.unix.admin:50511 comp.protocols.ppp:15914 comp.unix.questions:91386 comp.unix.bsd.freebsd.misc:31124 comp.unix.bsd.netbsd.misc:4867 In article <56le6q$2c6@panix2.panix.com>, Thor Lancelot Simon <tls@rek.tjls.com> wrote: >Curt pointed out that much of the larger multi-port serial-port hardware for >PCs is polled. I'm interested in the impact of this on throughput on those >serial ports; Curt, can you tell me more? As far as I know, thoughput is just fine. I don't know all the details of the Digiboards and whatnot, but I assume they work pretty much like the ones they used to use on the VAX. Each port has an input silo, and all of the handshaking and whatnot is taken care of by the board. Every few milliseconds or so you wander by and grab all of the data that's come in for all of the serial ports, and drop it up into the appropriate tty queues. Your latency is whatever your polling period is, so basically you decide what tradeoff you want to make between CPU usage and latency. Output is dead easy, you just write the biggest chunks you have (generally up to a kilobyte) into the output silo and wait for it to get sent. >I still think those Cirrus PPP-UARTS are way cool; I wish someone would build >cards for PCs that used them, other than the Cirrus demonstrator. I've got >programming specs, too. Well, I can't see any reason you couldn't make these intelligent serial boards just a bit more intelligent and teach them about SLIP and PPP framing. Then for ports you know you're running SLIP or PPP on, you delay the copy until you've got a full packet available in the silo. cjs -- Curt Sampson cjs@portal.ca Info at http://www.portal.ca/ Internet Portal Services, Inc. Vancouver, BC (604) 257-9400 De gustibus, aut bene aut nihil.