On 05/07/12 15:03, John Kacur wrote:
>
>
> On Mon, 7 May 2012, Frank Rowand wrote:
>
>> On 05/07/12 14:41, John Kacur wrote:
>>>
>>>
>>> On Wed, 2 May 2012, Frank Rowand wrote:
>>>
>>>>
>>>> When the --verbose option is selected, the first value for each thread is
>>>> incorrectly reported as zero.
>>>>
>>>> This is because when collecting the first value, the index into stat->values is
>>>> incremented from zero to one before storing the value. But when printing the
>>>> values, the first value printed is stat->values[0], which has been initialized
>>>> to zero.
>>>
>>> Hi Frank
>>>
>>> Ok, no more posting from me after winning a bottle of whiskey at the Irish
>>> Pub on quiz night. :)
>>
>> Or if you do, you should share a bit of the whiskey with me.
>
> You get the bottle and 30 shot glasses and share it with everyone at the
> pub, so if you want some you have to come, and then help my team win too
> :)
Hmmm, that's a long way to go for a shot.
>
> >
>>>
>>> I've been looking at this one, and I'm not sure about it.
>>> According to the help output,
>>>
>>> "-v --verbose output values on stdout for statistics
>>> format: n:c:v n=tasknum c=count v=value in us"
>>>
>>> ./cyclictest --verbose -p99 -t | awk '$2~/^0/{ print }'
>>>
>>> 0: 0: 0
>>> 1: 0: 0
>>> 2: 0: 0
>>> 3: 0: 0
>>> 4: 0: 0
>>> 5: 0: 0
>>> 6: 0: 0
>>> 7: 0: 0
>>>
>>> So, it looks like the values are 0 at count 0, doesn't that make sense?
>>
>> Nope. The event for count == 0 is the first event. And the first event
>> has an actual latency that is not zero on the system I tested it on.
>>
>
> Hmmm, this may be a quibble about definitions. I know that in the c-world
> we're used to start counting at 0, but to me, count == 0 is before the
> first event. You're not losing any data here, it's just that the first
> event is stored in the first count. Or am I still missing something here?
In that case, there is no value in reporting event zero for each thread,
because it will always be: 0: 0: 0
Another thing that points to reporting latency == 0 is not intended is
that the summary does not report a 'Min' of zero, even when the trace
shows the first event having a latency of zero:
# cyclictest -q --verbose -p99 -t -l 3
Thread 0 Interval: 1500
Thread 1 Interval: 2000
0: 0: 0
0: 1: 190
0: 2: 166
1: 0: 0
1: 1: 178
1: 2: 173
T: 0 ( 633) P:99 I:1000 C: 3 Min: 166 Act: 173 Avg: 176 Max: 190
T: 1 ( 634) P:98 I:1500 C: 3 Min: 138 Act: 138 Avg: 163 Max: 178
--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
