Date: Thu, 30 Mar 1995 17:45:05 -0700 From: Nate Williams <nate@trout.sri.MT.net> To: davidg@Root.COM, terry@cs.weber.edu (Terry Lambert) Cc: freebsd-hackers@FreeBSD.org Subject: Re: help with splbio, splnet, spl... Message-ID: <199503310045.RAA08865@trout.sri.MT.net> In-Reply-To: David Greenman <davidg@Root.COM> "Re: help with splbio, splnet, spl..." (Mar 30, 4:19pm)
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[ What do the spl* routines do? ] > >It's a tiered interrupt scheme. You can block all interrupts > >at or below a specified priority while you are doing high > >priority stuff so that it gets done in time. The "fast" > >interrupts can't be blocked. > > It doesn't work this way in FreeBSD. It is not a tierd interrupt scheme. > Each of the interrupt classes are independant and do NOT block the others. The > only exception to this is tty and net are ored together if you are using SLIP > or PPP (the reason should be obvious). Interesting. I wasn't aware that you could do this on a PC, since I was under the impression that you had to have a tiered scheme with the 8259. Obviously I was mis-informed since this would imply that no interrupt is given a higher priority over another interrupt. Is there any way this can be done short of OR'ing a lot of the different masks together to keep certain interrupts from happening? Is this how the sio driver does things? (I know, use the source...) Nate
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