Date: Tue, 12 Nov 2002 14:29:55 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: John Baldwin <jhb@FreeBSD.org> Cc: "Michael A. Mackey" <michael-mackey@uiowa.edu>, freebsd-alpha@freebsd.org Subject: Re: Extreme time drift in SMP mode Message-ID: <3DD180E3.80D3C4F6@mindspring.com> References: <XFMail.20021112164459.jhb@FreeBSD.org>
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John Baldwin wrote: > On 12-Nov-2002 Michael A. Mackey wrote: > > Well, I guess I got really lucky.... > > > > I seem to have fixed the time drift problem, based on a hunch. > > > > Drew, after what you said about the boot processor alone driving the > > timing, I decided to allow both processors to drive the timer. So, I > > changed the code in the function 'alpha_clock_interrupt ()' in > > /usr/src/sys/alpha/alpha/interrupt.c (actually I only added an #undef > > SMP statement on line 467 and redefined it before the 'critical_exit()' > > call). > > > > And now, the SMP system keeps proper track of the time. > > > > In a couple of days, I have two more processors arriving. Then I can > > really test if this fix works. > > > > Thanks for your help - and I hope others can verify my results. > > Well, that's not really an ideal fix for the problem. :( Adjusting > the timer frequency in the SMP case instead would be preferred. What if that's just a statistical fix, having to do with interrupt delivery, rather than a real fix? -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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