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SubjectRe: [RFC v2 1/3] PM / QoS: Add PM_QOS_MEMORY_BANDWIDTH class
Hi!

> Also adds a class type PM_QOS_SUM that aggregates the values by summing them.
>
> It can be used by memory controllers to calculate the optimum clock frequency
> based on the bandwidth needs of the different memory clients.
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> ---
> Documentation/power/pm_qos_interface.txt | 4 +++-
> include/linux/pm_qos.h | 5 ++++-
> kernel/power/qos.c | 27 ++++++++++++++++++++++++++-
> 3 files changed, 33 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt
> index a5da5c7..57782e8 100644
> --- a/Documentation/power/pm_qos_interface.txt
> +++ b/Documentation/power/pm_qos_interface.txt
> @@ -5,7 +5,8 @@ performance expectations by drivers, subsystems and user space applications on
> one of the parameters.
>
> Two different PM QoS frameworks are available:
> -1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput.
> +1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput,
> +memory_bandwidth.
> 2. the per-device PM QoS framework provides the API to manage the per-device latency
> constraints and PM QoS flags.
>
> @@ -13,6 +14,7 @@ Each parameters have defined units:
> * latency: usec
> * timeout: usec
> * throughput: kbs (kilo bit / sec)
> + * memory bandwidth: kbs (kilo bit / sec)

Would mega bits per second make sense here?

I suppose some many-core systems would have memory bandwith
in > 10 terabit/sec, overflowing u32.

Plus, if driver in 3/3 is just an example, perhaps comment
should explain that clearly?

Otherwise looks good,

Acked-by: Pavel Machek <pavel@ucw.cz>


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