[PATCH 1/2] drm/xe/guc: Default log level to non-verbose

[Matthew Brost]

On Thu, Jun 12, 2025 at 11:05:32AM -0700, Lucas De Marchi wrote:
> Currently xe sets the guc log level to a verbose level since it's useful
> to debug hangs and general development. However the verbose level may
> already be too much and affect performance.
> 
> Michal Mrozek did some tests with the L0 compute stack for submission
> latency with ULLS disabled. Below are the normalized numbers with log
> level 3 (the current default) as baseline for each test:
> 
>                           Test \ Log Level                        3      0      1      2
>  ----------------------------------------------------------- ------ ------ ------ ------
>   BestWalkerNthCommandListSubmission(CmdListCount=2)           1.00   0.63   0.63   0.96
>   BestWalkerNthSubmission(KernelCount=2)                       1.00   0.62   0.63   0.96
>   BestWalkerNthSubmissionImmediate(KernelCount=2)              1.00   0.58   0.58   0.85
>   BestWalkerSubmission                                         1.00   0.62   0.62   0.96
>   BestWalkerSubmissionImmediate                                1.00   0.63   0.62   0.96
>   BestWalkerSubmissionImmediateMultiCmdlists(cmdlistCount=2)   1.00   0.58   0.58   0.86
>   BestWalkerSubmissionImmediateMultiCmdlists(cmdlistCount=4)   1.00   0.70   0.70   0.83
>   BestWalkerSubmissionImmediateMultiCmdlists(cmdlistCount=8)   1.00   0.53   0.52   0.78
> 
> Log level 2 is the first "verbose level" for GuC, where the biggest
> difference happens. Keep log level 3 for CONFIG_DRM_XE_DEBUG, but switch
> to 1, i.e.  GUC_LOG_LEVEL_NON_VERBOSE, for "normal" builds.
> 

For series in general, I think this is a good idea - no need to slow
down performance for customers.

Downside is devcoredump from customers are going to have less
information. I'm wondering if the GuC log level is low, if we should
print something in devcoredump indicating this, and instructions on how
to turn up the GuC log level for filing verbose bug reports? e.g., A
similar message to what we print in xe_device_declare_wedged?

Matt 

> Cc: Michal Mrozek <michal.mrozek at intel.com>
> Cc: John Harrison <John.C.Harrison at Intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_module.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
> index 1c4dfafbcd0bc..4809afa7ce3f9 100644
> --- a/drivers/gpu/drm/xe/xe_module.c
> +++ b/drivers/gpu/drm/xe/xe_module.c
> @@ -20,7 +20,7 @@
>  
>  struct xe_modparam xe_modparam = {
>  	.probe_display = true,
> -	.guc_log_level = 3,
> +	.guc_log_level = IS_ENABLED(CONFIG_DRM_XE_DEBUG) ? 3 : 1,
>  	.force_probe = CONFIG_DRM_XE_FORCE_PROBE,
>  #ifdef CONFIG_PCI_IOV
>  	.max_vfs = IS_ENABLED(CONFIG_DRM_XE_DEBUG) ? ~0 : 0,
> 
> -- 
> 2.49.0
>