[Intel-gfx] [PATCH] drm/i915: Add device name to display tracepoints

[Chris Wilson]

Quoting Ville Syrjala (2019-12-13 15:28:23)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Include dev_name() in the tracpoints so one can filter based on
> the device.
> 
> Example:
> echo 'dev=="0000:00:02.0"' > events/i915/intel_cpu_fifo_underrun/filter
> 
> TODO: maybe don't both specifying the field name always and just
>       make it 'dev' (or whatever) always?
> TODO: add for other tracpoints too if this is deemed good enough
> 
> Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_trace.h | 96 +++++++++++++++++++++----------
>  1 file changed, 65 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
> index 7ef7a1e1664c..8931b6756f44 100644
> --- a/drivers/gpu/drm/i915/i915_trace.h
> +++ b/drivers/gpu/drm/i915/i915_trace.h
> @@ -20,11 +20,18 @@
>  
>  /* watermark/fifo updates */
>  
> +#define __dev_name_i915(field, i915) __string(field, dev_name((i915)->drm.dev))
> +#define __dev_name_crtc(field, crtc) __string(field, dev_name((crtc)->base.dev->dev))
> +#define __assign_dev_name_i915(field, i915) __assign_str(field, dev_name((i915)->drm.dev))
> +#define __assign_dev_name_crtc(field, crtc) __assign_str(field, dev_name((crtc)->base.dev->dev))
> +#define __get_dev_name(field) __get_str(field)

Storing the string is quite expensive, I thought. Can we stash the i915
and stringify in the TP_printk? Or is stashing the string the secret for
the dev== filter?
-Chris