On Mon, Apr 08, 2019 at 09:10:00PM +0000, Adham.Abozaeid@xxxxxxxxxxxxx wrote:
> Hi Nicholas
>
> On 4/6/19 5:01 AM, Nicholas Mc Guire wrote:
> > External E-Mail
> >
> >
> > Someone that knows the motivation for setting the time to 2 millisecond
> > might need to check if the 2 milliseconds where seen as tollerable max or
> > min - I'm assuming it was the min so extending.
>
> 2 msec is the time the chip takes to wake up from sleep.
>
> Increasing the maximum to 5 msec will impact the throughput since this call is on the transmit path.
>
ok - would it be tollerable to make it 2 - 2.5 ms ?
even that would allow for the hrtimer subsystem to optimize
a lot. In any case the min==max case gives you very little
if you run a test-case with usleep_range(1000,1000) and
a loop with usleep_range(1000,2000) and look at the distribution
you will have a hard time seeing any difference.
I doubt you would readily see the change from usleep_range(2000,2000)
to usleep_range(2000,3000) in benchmarks - maybe (2000,5000) would
be visible.
My assumption (I have not analyzed it in detail) is that if
you have a high re-use of existing timers that the setup of the timer
is faster and thats why increasing the range > 0 can actually result
in better jitter distribution.
thx!
hofrat
> > diff --git a/drivers/staging/wilc1000/wilc_wlan.c b/drivers/staging/wilc1000/wilc_wlan.c
> > index c238969..42da533 100644
> > --- a/drivers/staging/wilc1000/wilc_wlan.c
> > +++ b/drivers/staging/wilc1000/wilc_wlan.c
> > @@ -408,7 +408,7 @@ void chip_wakeup(struct wilc *wilc)
> > wilc->hif_func->hif_write_reg(wilc, 1, reg & ~BIT(1));
> >
> > do {
> > - usleep_range(2 * 1000, 2 * 1000);
> > + usleep_range(2 * 1000, 5 * 1000);
> > wilc_get_chipid(wilc, true);
> > } while (wilc_get_chipid(wilc, true) == 0);
> > } while (wilc_get_chipid(wilc, true) == 0);
> > @@ -423,7 +423,7 @@ void chip_wakeup(struct wilc *wilc)
> > &clk_status_reg);
> >
> > while ((clk_status_reg & 0x1) == 0) {
> > - usleep_range(2 * 1000, 2 * 1000);
> > + usleep_range(2 * 1000, 5 * 1000);
> >
> > wilc->hif_func->hif_read_reg(wilc, 0xf1,
> > &clk_status_reg);
>
>
> Thanks,
>
> Adham
>
