Re: [patch] 2.4.1, 2.4.2-pre3: APIC lockups

From: Manfred Spraul (
Date: Tue Feb 13 2001 - 17:18:09 EST

"Maciej W. Rozycki" wrote:
> Hi,
> After performing various tests I came to the following workaround for
> APIC lockups which people observe under IRQ load, mostly for networking
> stuff. I believe the test should work in all cases as it basically
> implements a manual replacement for EOI messages. In my simulated
> environment I was unable to get a lockup with the code in place, even
> though I was getting about every other level-triggered IRQ misdelivered.
> Please test it extensively, as much as you can, before I submit it for
> inclusion. If you ever get "Aieee!!! Remote IRR still set after unlock!"
> message, please report it to me immediately -- it means the code failed.
No messages.

> There is also an additional debugging/statistics counter provided in
> /proc/cpuinfo that counts interrupts which got delivered with its trigger
> mode mismatched. Check it out to find if you get any misdelivered
> interrupts at all.
I'm running my default webserver load test, and I get ~40 /second, 92735

bw_tcp says 1.13 MB/sec, that's wire speed.

tcpdump | grep 'sack ' doesn't show unusually many lost packets.

Look promising.

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This archive was generated by hypermail 2b29 : Thu Feb 15 2001 - 21:00:22 EST