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- Newsgroups: comp.arch
- Path: sparky!uunet!gatech!willis.cis.uab.edu!hyatt
- From: hyatt@cis.uab.edu (Robert Hyatt)
- Subject: Re: MP interrupt handling was(Re: Sun 600MP Benchmark Anomaly)
- Message-ID: <1992Jul24.133407.18743@cis.uab.edu>
- Sender: root@cis.uab.edu (Bruce Williams)
- Organization: University of Alabama at Birmingham
- References: <BrKMq3.6D4@acsu.buffalo.edu> <1992Jul20.150259.16021@crd.ge.com> <21b002x91bnp01@JUTS.ccc.amdahl.com>
- Date: Fri, 24 Jul 1992 13:34:07 GMT
- Lines: 31
-
- In article <1992Jul20.150259.16021@crd.ge.com> davidsen@crd.ge.com (bill davidsen) writes:
- >
- >
- > As a general question, which machines do this now? When GE was in the
- >mainframe business we never did it, the kernel was totally shared but
- >all hardware interrupts came to the same processor. I think DTSS did
- >that, too, but could change the processor if the master went down.
- >--
- >bill davidsen, GE Corp. R&D Center; Box 8; Schenectady NY 12345
- > It never ceases to amaze me that otherwise rational people, able to
- > understand calculus, compound interest, and the income tax form, can
- > continue to believe that poker is a game of chance.
-
- The Sequent systems use the SLIC bus to control interrupts. Using this bus,
- the priority of what each CPU is doing is globally available and the CPU
- running the lowest priority task (usually in the kernel IDLE loop) fields
- an interrupt when it occurs.
-
- Cray has a more complex scheme concerning which cpu originated the request,
- the interrupt mask of that cpu (and the others) etc. Hopefully routing the
- interrupt to the cpu that is best able to handle it.
-
- As near as I can tell, the new SUN MP systems have symmetric hardware where
- any cpu can field an interrupt, but I don't know how a SUN multiprocessor
- arbitrates who (whom?) gets an interrupt when all cpus are interrupt-
- enabled. Apparently the "big lock" problem currently hangs the suns....
-
- Bob
- --
- !Robert Hyatt Computer and Information Sciences !
- !hyatt@cis.uab.edu University of Alabama at Birmingham !
-