[PATCH v2] drm/amd/pm: Increase cache interval time

[Alex Deucher]

On Tue, Aug 5, 2025 at 11:51 AM Asad Kamal <asad.kamal at amd.com> wrote:
>
> Increase cache interval time to 50 ms while fetching system
> metrics table for smu_v13_0_12 since polling interval is less frequent for
> this data.
>
> v2: Make caching interval soc independent, however customization can be
> done in soc specific callbacks(Alex/Lijo)

I would split this into two patches, one to add the soc independent
change, and one to adjust smu 13.0.12.  We also need to implement the
cache implementation in the smu backend code for other chips.  It
would be nice to move that logic to a higher level so each smu backend
doesn't have to implement the caching.

Alex

>
> Signed-off-by: Asad Kamal <asad.kamal at amd.com>
> ---
>  drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c             | 4 ++++
>  drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h         | 3 +++
>  drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_12_ppt.c | 9 ++++-----
>  3 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
> index dc48a1dd8be4..c62d68d7410f 100644
> --- a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
> +++ b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
> @@ -1162,8 +1162,12 @@ static void smu_free_dummy_read_table(struct smu_context *smu)
>
>  static int smu_smc_table_sw_init(struct smu_context *smu)
>  {
> +       struct smu_table_context *smu_table = &smu->smu_table;
>         int ret;
>
> +       smu_table->tables[SMU_TABLE_TEMP_METRICS].cache_interval =
> +               AMDGPU_TEMP_METRICS_CACHE_INTERVAL;
> +
>         /**
>          * Create smu_table structure, and init smc tables such as
>          * TABLE_PPTABLE, TABLE_WATERMARKS, TABLE_SMU_METRICS, and etc.
> diff --git a/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h b/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
> index 611b381b9147..7a52c00c700e 100644
> --- a/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
> +++ b/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
> @@ -32,6 +32,8 @@
>  #include "smu_types.h"
>  #include "linux/firmware.h"
>
> +#define AMDGPU_TEMP_METRICS_CACHE_INTERVAL     50
> +
>  #define SMU_THERMAL_MINIMUM_ALERT_TEMP         0
>  #define SMU_THERMAL_MAXIMUM_ALERT_TEMP         255
>  #define SMU_TEMPERATURE_UNITS_PER_CENTIGRADES  1000
> @@ -258,6 +260,7 @@ struct smu_table {
>         struct amdgpu_bo *bo;
>         uint32_t version;
>         unsigned long  metrics_time;
> +       uint32_t cache_interval;
>  };
>
>  enum smu_perf_level_designation {
> diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_12_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_12_ppt.c
> index fca50f6a8ef6..5ead66375d38 100644
> --- a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_12_ppt.c
> +++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_12_ppt.c
> @@ -361,18 +361,17 @@ int smu_v13_0_12_get_smu_metrics_data(struct smu_context *smu,
>         return 0;
>  }
>
> -static int smu_v13_0_12_get_system_metrics_table(struct smu_context *smu, void *metrics_table,
> -                                                bool bypass_cache)
> +static int smu_v13_0_12_get_system_metrics_table(struct smu_context *smu, void *metrics_table)
>  {
>         struct smu_table_context *smu_table = &smu->smu_table;
>         uint32_t table_size = smu_table->tables[SMU_TABLE_SMU_METRICS].size;
>         struct smu_table *table = &smu_table->driver_table;
>         int ret;
>
> -       if (bypass_cache || !smu_table->tables[SMU_TABLE_TEMP_METRICS].metrics_time ||
> +       if (!smu_table->tables[SMU_TABLE_TEMP_METRICS].metrics_time ||
>             time_after(jiffies,
>                        smu_table->tables[SMU_TABLE_TEMP_METRICS].metrics_time +
> -                      msecs_to_jiffies(1))) {
> +                      msecs_to_jiffies(smu_table->tables[SMU_TABLE_TEMP_METRICS].cache_interval))) {
>                 ret = smu_cmn_send_smc_msg(smu, SMU_MSG_GetSystemMetricsTable, NULL);
>                 if (ret) {
>                         dev_info(smu->adev->dev,
> @@ -544,7 +543,7 @@ static ssize_t smu_v13_0_12_get_temp_metrics(struct smu_context *smu,
>         else if (type  == SMU_TEMP_METRIC_BASEBOARD)
>                 smu_cmn_init_baseboard_temp_metrics(baseboard_temp_metrics, 1, 0);
>
> -       ret = smu_v13_0_12_get_system_metrics_table(smu, metrics, false);
> +       ret = smu_v13_0_12_get_system_metrics_table(smu, metrics);
>         if (ret) {
>                 kfree(metrics);
>                 return ret;
> --
> 2.46.0
>