Re: [PATCH] kvm-unit-tests: x86: pmu: call measure for every counter in check_counters_many

[Chris J Arges <chris.j.arges@canonical.com>]

On 08/25/2014 02:32 PM, Paolo Bonzini wrote:
>> Ok I see now where this patch doesn't make sense.
>> With the latest kvm tree I get:
>>
>> sudo ./x86-run x86/pmu.flat -smp 1 -cpu host | grep -v PASS
>>
>>
>> qemu-system-x86_64 -enable-kvm -device pc-testdev -device
>> isa-debug-exit,iobase=0xf4,iosize=0x4 -display none -serial stdio
>> -device pci-testdev -kernel x86/pmu.flat -smp 1 -cpu host
>> enabling apic
>> paging enabled
>> cr0 = 80010011
>> cr3 = 7fff000
>> cr4 = 20
>> PMU version:         2
>> GP counters:         4
>> GP counter width:    48
>> Mask length:         7
>> Fixed counters:      3
>> Fixed counter width: 48
>> FAIL: all counters
>>
>> SUMMARY: 67 tests, 1 unexpected failures
>> Return value from qemu: 3
>>
>> I've tested this on a few Intel platforms (sandybridge/haswell), I'll
>> look into the code more then.
> 
> 
> Are you using the NMI watchdog in the host?  It eats one PMU counter
> and makes this test fail.
> 
> Paolo
> 

Ah, I didn't know that. Yes disabling NMI watchdog via:
echo 0 | sudo tee /proc/sys/kernel/nmi_watchdog
Allows this test to pass.

Would it make sense to have a check if nmi_watchdog is enabled in this
test case, and skip the all counters test?

--chris j arges