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Date:      Mon, 21 Apr 1997 04:13:21 +0200
From:      Terje Normann Marthinussen <Terje.N.Marthinussen@cc.uit.no>
To:        Steve Passe <smp@csn.net>
Cc:        freebsd-smp@freefall.freebsd.org
Subject:   Re: Current runs fine on 4 CPU's as well 
Message-ID:  <199704210213.EAA03641@slibo.cc.uit.no>
In-Reply-To: Your message of "Sun, 20 Apr 1997 19:28:09 METDST." <199704210128.TAA08535@Ilsa.StevesCafe.com> 

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>Hi,
>
>> Just sup'ed current, made the world and a new SMP kernel (suped 1 hour ago).
>>  ...
>> It's been running on 4 CPU's now since december, and I've only had two 
>> crashes since then. It's not heavily loaded, but when it once in a while
>> is loaded, it quite loaded chewing data that needs 50-100MB of memory
>> and sometimes causing heavy paging as well (got 128MB on it).
>
>Cyrus recently identified a dead-lock in the APIC_IO version.  The symptom
>is a complete freeze of the system while doing heavy IO.  

Yes, I've followed the discussion.

However, I've never seen the symptom, and it has made me wonder, probably
just luck. In most cases the things this machine have done so far while
running FreeBSD, has been tuned to fit into memory.

However, I had one case while running the last pre-lite code, where I 
totally miscalculated memory need for an application here.

I should run 3 instances in parallell and the code frequently traversed
some large arrays. I thought all three processes should run nice in 90MB, 
however, I did something very stupid so each process used 60MB instead 
of 30.

Had it trashing like mad on two 7200rpm FW HP disks while I was away for 
4 days. It didn't manage to do much work due to the trashing, but it 
didn't crash either.

On the other side, this machine is standing in a server room. And since
it hasn't yet been put to the work it should do, it seldom has to deal 
with more than a couple of shell users, and only does some chewing
when we don't have spare disk/cpu other more powerfull boxes.

So, I'll have to admit that the usage it's probably not the best 
to find bugs.

>Are you using the APIC_IO version?

Used APIC_IO since before christmas.

>When you say "crash", do you mean spontanious reboot, panic, or freeze?

One reboot during the night and one panic that I never cared to follow
up. Might have been other reboots, but at least I haven't seen them.

Well, I should admit, there is one more, it was when I tested the 
famous FP exception problem. But running code that one knows will 
crash the system hardly counts in this case.

>Earlier today I commited a "bandaid" that should help with this problem.
>Did you get the version of mpapic.h that has "#define APICIPI_BANDAID" in it?

Yes.

Terje Marthinussen
terjem@cc.uit.no





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