Date: Tue, 22 Jun 2004 17:50:05 -0400 From: Gerrit Nagelhout <gnagelhout@sandvine.com> To: 'Matthew Dillon' <dillon@apollo.backplane.com>, John Baldwin <jhb@FreeBSD.org>, Don Bowman <don@sandvine.com> Cc: Julian Elischer <julian@elischer.org> Subject: RE: STI, HLT in acpi_cpu_idle_c1 Message-ID: <FE045D4D9F7AED4CBFF1B3B813C85337054EC4AD@mail.sandvine.com>
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> : > :On Thursday 17 June 2004 07:33 pm, Matthew Dillon wrote: > :> It kinda sounds like ACPI has bokered the other cpus. > I'm not sure > :> why one would even *want* to use ACPI to idle down > Xeon's in an MP > :> system, actually :-) > : > :Power and heat savings. > : > :-- > :John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ > > All well and nice, but if you want power and heat savings > you don't > purchase a big honking SMP box in the first place. > > This sounds like a disaster waiting to happen to me. > ACPI barely works > on UP systems, there is no way I would ever trust it to > properly HLT or > otherwise screw around with the cpu timing on an SMP > system. HLT is > plenty good enough. IMHO this type of feature is not > something that > should be turned on by default on SMP. I am working with Don Bowman to try and debug this problem (the lockup). I have an emulator attached, and managed to get it into the locked up state. Three of the cpus are in idle (acpi_cpu_c1) (and have interrupts enabled, EFLAGS=0x246), and the other one (cpu 3) is in smp_tlb_shootdown waiting for one more processor to respond. The APIC register for CPU 3 (icr_lo) indicates that the IPI (0xf3) has been sent (ie it's idle). The isr registers for CPU 1 indicate that vector oxf3 is pending, but it is not being handled. I am still trying to figure out why this is, but does anyone have any suggested on what else I can look at? Thanks, Gerrit
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