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SubjectRe: [RFC 00/13] perf: Add perf kwork
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Hello,

On 2022/6/23 22:25, Paul A. Clarke wrote:
> On Thu, Jun 23, 2022 at 09:02:45AM +0800, Yang Jihong wrote:
>> On 2022/6/22 22:59, Paul A. Clarke wrote:
>>> On Mon, Jun 13, 2022 at 05:45:52PM +0800, Yang Jihong wrote:
>>>> Sometimes, we need to analyze time properties of kernel work such as irq,
>>>> softirq, and workqueue, such as delay and running time of specific interrupts.
>>>> Currently, these events have kernel tracepoints, but perf tool does not
>>>> directly analyze the delay of these events
>>>>
>>>> The perf-kwork tool is used to trace time properties of kernel work
>>>> (such as irq, softirq, and workqueue), including runtime, latency,
>>>> and timehist, using the infrastructure in the perf tools to allow
>>>> tracing extra targets
>>>>
>>>> test case:
>>>>
>>>> # perf kwork report
>>>>
>>>> Kwork Name | Cpu | Total Runtime | Frequency | Max runtime | Max runtime start | Max runtime end |
>>>> ---------------------------------------------------------------------------------------------------------------------------
>>>> (s)RCU:9 | 0007 | 3.488 ms | 1258 | 0.145 ms | 3398384.220013 s | 3398384.220157 s |
>>>> (s)NET_RX:3 | 0003 | 1.866 ms | 156 | 0.042 ms | 3398385.629764 s | 3398385.629806 s |
>>>> (s)TIMER:1 | 0000 | 1.799 ms | 117 | 0.055 ms | 3398385.568033 s | 3398385.568088 s |
>>>> (w)0xffff9c66e563ee98 | 0006 | 1.561 ms | 5 | 0.351 ms | 3398384.060021 s | 3398384.060371 s |
>>>
>>> What units are used for "Frequency"? It would be helpful to include somewhere.
>
>> This refers to the number of event in the trace period.
>
> I see. I suggest changing the column heading to say that.
> "Count", "Number of Events", "Occurrences", something like that.
>
> "Frequency" is a count-per-time-unit, like hertz, which doesn't
> match well here.

OK, I'll fix in next version.

Thanks,
Jihong

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