Date: Thu, 20 May 1999 17:15:51 -0700 From: Mike Smith <mike@smith.net.au> To: Joel Ray Holveck <joelh@gnu.org> Cc: Doug Rabson <dfr@nlsystems.com>, Peter Wemm <peter@netplex.com.au>, Tommy Hallgren <thallgren@yahoo.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Lazy SPLs Message-ID: <199905210015.RAA01979@dingo.cdrom.com> In-Reply-To: Your message of "20 May 1999 19:17:42 CDT." <86wvy3wa1l.fsf@detlev.UUCP>
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> >>> "Lazy SPLs - The kernel no longer masks hardware events unless a > >>> hardware event actually occurs, avoiding many expensive > >>> operations." > >> We've been doing it for as long as I can remember, at least as far > >> back as 2.0.5, probably as far back as 1.x. > > My earliest memory of it was as "Bruce's new interrupt code" for 386bsd. > > It was part of the 386bsd patchkit I think. > > Why mask out the interrupts at all, instead of queuing them in handler > level? Level-triggered interrupts are persistent conditions, not queueable events. They typically require device-driver level intervention to be cleared. This is a major error in the PCI design (no surprises there). -- \\ The mind's the standard \\ Mike Smith \\ of the man. \\ msmith@freebsd.org \\ -- Joseph Merrick \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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