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List:       freebsd-smp
Subject:    Re: 370DLE motherboard
From:       Mike Smith <msmith () FreeBSD ! ORG>
Date:       2000-08-28 8:53:23
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> 
> Just tested on Supermicro 370DLE motherboard and had problem with dual CPU.

These aren't actually "problems" as such; they're fairly consistent with 
expected results.

> The fxp0 is the primary network link, and the sk0 is a back-to-back connection
> to the other 370DLE (both are identical).
> 
> With one CPU installed, the sk0 throughput is 900 Mbps.
> With two CPU installed, the sk0 throughput drops to 837 Mbps (non_SMP kernel).
> With two CPU installed + SMP kernel, the sk0 throughput drops to 770 Mbps.
> 
> Case 1 and 3 are expected, however, the case 2 is NOT expected (non_SMP kernel).

Actually, it's not entirely unexpected.  I'd accept that even if the 
second CPU is idle, there is extra latency somewhere in the chipset due 
to its presence.

> The dmesg shows some information about timer (8254) interrupt issue.
> 
> APIC_IO: Testing 8254 interrupt delivery
> APIC_IO: Broken MP table detected: 8254 is not connected to IOAPIC #0 intpin 2
> APIC_IO: routing 8254 via 8259 and IOAPIC #0 intpin 0
> Waiting 7 seconds for SCSI devices to settle
> SMP: AP CPU #1 Launched!
> 
> Both machines have the same message. I wonder if the 4.1 does not recognize
> the board well, or there is something wrong with "ServerWork LE" chipset.

No, this is a harmless bug.  It's common for systems to lie about the 
8254 interrupt routing, and we should probably complain less bitterly 
about it.



-- 
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also.  But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view.  [Dr. Fritz Todt]




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