s/dmpis/dmips/ in $subject
On 29-10-18, 17:23, Daniel Lezcano wrote:
> In the case of assymetric SoC with the same micro-architecture, we
asymmetric ?
> have a group of CPUs with smaller OPPs than the other group. One
> example is the 96boards dragonboard 820c. There is no dmips/MHz
> difference between both groups, so no need to specify the values in
> the DT. Unfortunately, without these defined, there is no scaling
> capacity comutation triggered, so we need to write
computation
> 'capacity-dmips-mhz' for each CPU with the same value in order to
> force the scaled capacity computation.
>
> Fix this by setting a default capacity to SCHED_CAPACITY_SCALE, if no
> 'capacity-dmips-mhz' is defined in the DT.
>
> This was tested on db820c:
> - specified values in the DT (correct results)
> - partial values defined in the DT (error + fallback to defaults)
> - no specified values in the DT (correct results)
>
> correct results are:
> cat /sys/devices/system/cpu/cpu*/cpu_capacity
> 758
> 758
> 1024
> 1024
>
> ... respectively for CPU0, CPU1, CPU2 and CPU3.
>
> That reflects the capacity for the max frequencies 1593600 and 2150400.
>
> Cc: Chris Redpath <chris.redp...@linaro.org>
> Cc: Quentin Perret <quentin.per...@linaro.org>
> Cc: Viresh Kumar <viresh.ku...@linaro.org>
> Cc: Amit Kucheria <amit.kuche...@linaro.org>
> Cc: Nicolas Dechesne <nicolas.deche...@linaro.org>
> Cc: Niklas Cassel <niklas.cas...@linaro.org>
> Signed-off-by: Daniel Lezcano <daniel.lezc...@linaro.org>
> ---
> drivers/base/arch_topology.c | 27 ++++++++++++++++++++++++++-
> 1 file changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index 7311641..7d594a6 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -205,6 +205,21 @@ static struct notifier_block init_cpu_capacity_notifier
> = {
> .notifier_call = init_cpu_capacity_callback,
> };
>
> +static int topology_set_default_capacity(void)
> +{
> + int cpu;
> +
> + raw_capacity = kzalloc(num_possible_cpus() * sizeof(*raw_capacity),
> + GFP_KERNEL);
> + if (!raw_capacity)
> + return -ENOMEM;
> +
> + for_each_possible_cpu(cpu)
> + raw_capacity[cpu] = SCHED_CAPACITY_SCALE;
This isn't actually required as the value of raw_capacity isn't used
anymore after this point in code. Rather it is forcefully updated in
init_cpu_capacity_callback():
raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) *
policy->cpuinfo.max_freq / 1000UL;
Maybe it is better to allocate raw_capacity once at boot and use
another global variable as flag (raw_capacity is used as a flag right
now at many places).
--
viresh
