David, On Thu, Jun 12, 2014 at 1:13 PM, David Riley <[email protected]> wrote: > Create a module that allows udelay() to be executed to ensure that > it is delaying at least as long as requested (with a little bit of > error allowed). > > There are some configurations which don't have reliably udelay > due to using a loop delay with cpufreq changes which should use > a counter time based delay instead. This test aims to identify > those configurations where timing is unreliable. > > Signed-off-by: David Riley <[email protected]> > --- > kernel/time/Kconfig | 7 ++ > kernel/time/Makefile | 1 + > kernel/time/udelay_test.c | 170 > ++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 178 insertions(+)
Looks good to me. Also properly demonstrates that utter brokenness that is udelay on exynos5420 and exynos5800 right now upstream, like: 171 usecs x 100: exp=171000 allowed=170145 min=57791 avg=61586 max=435750 FAIL=99 ...the same kernel on exynos5250 shows all passes (though I didn't stress the low speeds where there are known problems due to the intermediate freq transition). Reviewed-by: Doug Anderson <[email protected]> Tested-by: Doug Anderson <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
