Re: [PATCH v3] power: new trace event to print device suspend andresume time

[Shuah Khan]

On 07/18/2013 08:21 AM, Steven Rostedt wrote:
> On Thu, 2013-07-18 at 14:00 +0000, Shuah Khan wrote:
>
>>>
>>> Don't you want to convert the ops_time on display? You can have:
>>>
>>> 	TP_printk("%s %s parent=%s state=%s ops=%snsecs=%lld err=%d",
>>> 		__get_str(driver), __get_str(device), __get_str(parent),
>>> 		__get_str(pm_event_str), __get_str(pm_ops),
>>> 		ktime_to_ns(__entry->ops_time), __entry->error)
>>>
>>>
>>> -- Steve
>>
>> I decided to pass in the converted value to the tracepoint. Please see
>> the drivers/base/power/main.c call to trace_device_pm_report_time()
>
> But why? You are still doing the calculation in the fast path. The
> TP_printk() is in the slow path. Why add overhead to the execution of
> the code?
>
> -- Steve

Yes. You are right. I want to avoid passing in ktime_t, I can still do 
that without doing the conversion in fast path. I could pass in tv64 
value and do the conversion in TP_printk.

Hopefully I will get this right this time. This is my first tracepoint. 
Thanks for your patience.

-- Shuah

-- 
Shuah Khan, Linux Kernel Developer - Open Source Group Samsung Research 
America (Silicon Valley) shuah.kh@xxxxxxxxxxx | (970) 672-0658
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/