Proposed 6.2 em RELEASE patch
scottl at samsco.org
Mon Nov 13 01:48:07 UTC 2006
Mike Tancsa wrote:
> At 11:41 AM 11/12/2006, Scott Long wrote:
>> Mike Tancsa wrote:
>>> At 01:42 AM 11/11/2006, Scott Long wrote:
>>> driver. What will help me is if you can hook up a serial console to
>>>> your machine and see if it can be made to drop to the debugger while it
>>>> is under load and otherwise unresponsive. If you can, getting a
>>>> dump might help confirm where each CPU is spending its time.
>>> ./netblast 192.168.88.218 500 110 1000
>>> I compiled in the various debugging options and on the serial console
>>> I get a few
>>> Expensive timeout(9) function: 0xc0601e48(0) 0.024135749 s
>>> and the serial console
>> One CPU seems to be stuck in softclock. My guess here is that there
>> is significant lock contention. Please try the following:
>> 1. Use addr2line or gdb on the kernel to find out what function is at
>> 0xc0601e48 (the address that was printed above). This address will
>> change every time you recompile the kernel, so you'll need to reacquire
>> it from the console each time.
> # addr2line 0xc0601e48 -e kernel.debug -f
Can you try removing NFS from your kernel?
> # addr2line 0xc0561444 -e kernel.debug -f
This is sched_lock contention.
> I dont have any nfs activity on the box
>> 2. Try compiling in WITNESS and running the test as before, then break
>> into the debugger as before. Run 'show locks'. I'm not sure how
>> fruitful this will be, WITNESS might make it unbearably slow.
> It was in that kernel already
So you're seeing the livelock under load while also having WITNESS
enabled? Have you tried your test without WITNESS? What about INVARIANTS?
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