Date: Mon, 12 Aug 2002 13:38:24 -0700 From: Maksim Yevmenkin <myevmenk@exodus.net> To: Bruce Evans <bde@zeta.org.au> Cc: Maksim Yevmenkin <Maksim.Yevmenkin@exodus.net>, current@FreeBSD.ORG Subject: Re: Interrupt vs. polling on -current Message-ID: <3D581CC0.8B91EFE2@exodus.net> References: <20020813051700.M25922-100000@gamplex.bde.org>
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Bruce Evans wrote: > > On Mon, 12 Aug 2002, Maksim Yevmenkin wrote: > > > Bruce Evans wrote: > > > > > > On Sun, 11 Aug 2002, Maksim Yevmenkin wrote: > > [...] > > > > > > BTW, i see "silo overflow" messages when i run ppp via null-modem > > > > cable. in this configuration i'm using serial port 0 which is on > > > > board and hase irq 4 with fast interrupts. > > > > > > What else is active when you get these? > > > > not much: X, user space ppp and i'm doing moderate size transfers > > via ftp between my current laptop and FreeBSD 4.5 desktop. i also > > see these errors while cvsup'ing my -current laptop. > > Some graphics cards can cause sio problems, by using too bus cycles so > that sio doesn't get even an average of about 5 i/o cycles per character > time that it needs to function. 5 might sound like not many, but it is > 5 isa cycles so it takes 6 usec every 87 usec at 115200 bps. 20 devices > wanting that much of the bus just won't work. WHOA! that scares the hell out of me. You sound like any hardware that uses interrupt/bus might hurt poor "sio" driver pretty badly. There is not much use in computer that has only CPU and serial port :) i'm not trying to blame anybody here, but rather understand what is wrong. BTW, i have s3 savage/mx and neomagic/av video cards in my laptops. thanks, max To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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