Re: Recommended method of getting timestamps?

[Dmitry Vyal <dmitryvyal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hello Patrick,

I guess gettimeofday is too heavy if all you need is an abstract 
timestamp not related to any particular calendar. I think you should 
look at rte_rdtsc()? It returns a current value of CPU tick counter. So 
it's very cheap (just a few clocks) and has a great resolution (a 
fraction of nanosecond).

Regards,
Dmitry

> I have a need to keep a timestamp on a piece of global data.  When then timestamp grows too old I want to refresh that data.  Is it safe to use, gettimeofday()?
>
> I thought about using an alarm, but I need to set an alarm from inside the alarm callback which doesn't look like it will work due to the spinlock on the alarm list.
>
> And since this is inside the driver I am working on, setting up a timer is not simple.
>
> So, I figure to timestamp the data, wait until I need to access it, check the timestamp and refresh if it is too old.
>
> Thoughts?  Suggestions?
>
> Thanks,
>
> Patrick
>
> Coming to you from deep inside Fortress Mahan