Date: Thu, 05 Sep 2002 15:06:40 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: freebsd-alpha@freebsd.org Subject: RE: ithread preemption Message-ID: <XFMail.20020905150640.jhb@FreeBSD.org> In-Reply-To: <15735.38318.66517.366474@grasshopper.cs.duke.edu>
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On 05-Sep-2002 Andrew Gallatin wrote: > > I've forgotten -- What are the symptoms of ithread preemption causing > troubles on alpha? Hangs on SMP under load. > I have one (probably dumb) idea: Is the ithread preemption code > guaranteed to switch back to the preempted thread when the ithread > completes or blocks? And continue through to the end of the interrupt > dispatch code, returning back to the palcode? It is not guaranteed to do that. > Eg, I'm wondering if it could it have anything to do with continuing > to run at IPL_IO when we shouldn't be (like running a normal > process at that priority that the scheduler happened to run by mistake). Nope, IPL changes when you switch threads. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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