Hi Vaidy, On Thu, Aug 24, 2017 at 12:28:41AM +0530, Vaidyanathan Srinivasan wrote:
Cc'ing Rafael and linux-pm list. > On PowerNV platforms, firmware provides exit latency and > target residency for each of the idle states in nano > seconds. Cpuidle framework expects the values in micro > seconds. Round up to nearest micro seconds to avoid errors > in cases where the values are defined as fractional micro > seconds. > > Default idle state of 'snooze' has exit latency of zero. If > other states have fractional micro second exit latency, they > would get rounded down to zero micro second and make cpuidle > framework choose deeper idle state when snooze loop is the > right choice. > > Reported-by: Anton Blanchard <an...@samba.org> > Signed-off-by: Vaidyanathan Srinivasan <sva...@linux.vnet.ibm.com> This looks good to me. Reviewed-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com> > --- > drivers/cpuidle/cpuidle-powernv.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle-powernv.c > b/drivers/cpuidle/cpuidle-powernv.c > index 42896a67aeae..5f3922392059 100644 > --- a/drivers/cpuidle/cpuidle-powernv.c > +++ b/drivers/cpuidle/cpuidle-powernv.c > @@ -383,9 +383,9 @@ static int powernv_add_idle_states(void) > * Firmware passes residency and latency values in ns. > * cpuidle expects it in us. > */ > - exit_latency = latency_ns[i] / 1000; > + exit_latency = DIV_ROUND_UP(latency_ns[i], 1000); > if (!rc) > - target_residency = residency_ns[i] / 1000; > + target_residency = DIV_ROUND_UP(residency_ns[i], 1000); > else > target_residency = 0; > > -- > 2.13.5 >
