Re: Ques: [kernel/time/*] Is there any disadvantage in using usleep_range for more than 20ms delay ?

[Clemens Ladisch]

Aniroop Mathur wrote:
> As in the kernel documentation, it is mentioned to use msleep for
> 10ms+ delay, I am confused whether there would be any disadvantage in
> using usleep_range for higher delays values because normally drivers
> have variety of delays used (2, 10, 20, 40, 100, 500 ms).
>
> So, could you please help to confirm that if we use usleep_range for
> inserting delays greater than 20 ms, would it be harmful or beneficial
> or does not make any difference at all ?

As the documentation told you, usleep_range() is likely to require
a separate interrupt, while msleep() is likely to round to some other,
already-scheduled interrupt.  The former is possibly harmful regarding
CPU and power usage; you have to balance it against your need for
accuracy.

(And usleep_range() has a 32-bit nanosecond limit on 32-bit
architectures.)


Regards,
Clemens
--
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/