Re: [PATCH v4] Add power/gpu_frequency tracepoint.

[Peiyong Lin]

On Thu, Oct 22, 2020 at 10:34 AM Peiyong Lin <lpy@xxxxxxxxxx> wrote:
>
> Historically there is no common trace event for GPU frequency, in
> downstream Android each different hardware vendor implements their own
> way to expose GPU frequency, for example as a debugfs node.  This patch
> standardize it as a common trace event in upstream linux kernel to help
> the ecosystem have a common implementation across hardware vendors.
> Toolings in the Linux ecosystem will benefit from this especially in the
> downstream Android, where this information is critical to graphics
> developers.
>
> Signed-off-by: Peiyong Lin <lpy@xxxxxxxxxx>
> ---
>
> Changelog since v3:
>  - Correct copyright title.
>
> Changelog since v2:
>  - Add more comments to indicate when the event should be emitted.
>  - Change state to frequency.
>
> Changelog since v1:
>  - Use %u in TP_printk
>
>  drivers/gpu/Makefile                    |  1 +
>  drivers/gpu/trace/Kconfig               |  3 +++
>  drivers/gpu/trace/Makefile              |  1 +
>  drivers/gpu/trace/trace_gpu_frequency.c | 13 ++++++++++
>  include/trace/events/power.h            | 33 +++++++++++++++++++++++++
>  5 files changed, 51 insertions(+)
>  create mode 100644 drivers/gpu/trace/trace_gpu_frequency.c
>
> diff --git a/drivers/gpu/Makefile b/drivers/gpu/Makefile
> index 835c88318cec..f289a47eb031 100644
> --- a/drivers/gpu/Makefile
> +++ b/drivers/gpu/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_TEGRA_HOST1X)      += host1x/
>  obj-y                  += drm/ vga/
>  obj-$(CONFIG_IMX_IPUV3_CORE)   += ipu-v3/
>  obj-$(CONFIG_TRACE_GPU_MEM)            += trace/
> +obj-$(CONFIG_TRACE_GPU_FREQUENCY)              += trace/
> diff --git a/drivers/gpu/trace/Kconfig b/drivers/gpu/trace/Kconfig
> index c24e9edd022e..ac4aec8d5845 100644
> --- a/drivers/gpu/trace/Kconfig
> +++ b/drivers/gpu/trace/Kconfig
> @@ -2,3 +2,6 @@
>
>  config TRACE_GPU_MEM
>         bool
> +
> +config TRACE_GPU_FREQUENCY
> +       bool
> diff --git a/drivers/gpu/trace/Makefile b/drivers/gpu/trace/Makefile
> index b70fbdc5847f..2b7ae69327d6 100644
> --- a/drivers/gpu/trace/Makefile
> +++ b/drivers/gpu/trace/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0
>
>  obj-$(CONFIG_TRACE_GPU_MEM) += trace_gpu_mem.o
> +obj-$(CONFIG_TRACE_GPU_FREQUENCY) += trace_gpu_frequency.o
> diff --git a/drivers/gpu/trace/trace_gpu_frequency.c b/drivers/gpu/trace/trace_gpu_frequency.c
> new file mode 100644
> index 000000000000..668fabd6b77a
> --- /dev/null
> +++ b/drivers/gpu/trace/trace_gpu_frequency.c
> @@ -0,0 +1,13 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * GPU frequency trace points
> + *
> + * Copyright (C) 2020 Google LLC
> + */
> +
> +#include <linux/module.h>
> +
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/power.h>
> +
> +EXPORT_TRACEPOINT_SYMBOL(gpu_frequency);
> diff --git a/include/trace/events/power.h b/include/trace/events/power.h
> index af5018aa9517..343825a76953 100644
> --- a/include/trace/events/power.h
> +++ b/include/trace/events/power.h
> @@ -500,6 +500,39 @@ DEFINE_EVENT(dev_pm_qos_request, dev_pm_qos_remove_request,
>
>         TP_ARGS(name, type, new_value)
>  );
> +
> +/**
> + * gpu_frequency - Reports the GPU frequency in GPU clock domains.
> + *
> + * This event should be emitted whenever there's a GPU frequency change happens,
> + * or a GPU goes from idle state to active state, or vice versa.
> + *
> + * When the GPU goes from idle state to active state, this event should report
> + * the GPU frequency of the active state. When the GPU goes from active state to
> + * idle state, this event should report a zero frequency value.
> + *
> + * @frequency:  New frequency (in KHz)
> + * @gpu_id: Id for each GPU clock domain
> + */
> +TRACE_EVENT(gpu_frequency,
> +
> +       TP_PROTO(unsigned int frequency, unsigned int gpu_id),
> +
> +       TP_ARGS(frequency, gpu_id),
> +
> +       TP_STRUCT__entry(
> +               __field(unsigned int, frequency)
> +               __field(unsigned int, gpu_id)
> +       ),
> +
> +       TP_fast_assign(
> +               __entry->frequency = frequency;
> +               __entry->gpu_id = gpu_id;
> +       ),
> +
> +       TP_printk("frequency=%u gpu_id=%u",
> +               __entry->frequency, __entry->gpu_id)
> +);
>  #endif /* _TRACE_POWER_H */
>
>  /* This part must be outside protection */
> --
> 2.29.0.rc1.297.gfa9743e501-goog
>

Hi there,

May I ask whether the merge window has passed? If so is it possible to
ask for a review?

Thanks,
Peiyong