[Intel-gfx] [PATCH] drm/i915/guc: Dump perf_limit_reasons for debug

[Belgaumkar, Vinay]

On 6/26/2023 11:43 PM, Dixit, Ashutosh wrote:
> On Mon, 26 Jun 2023 21:02:14 -0700, Belgaumkar, Vinay wrote:
>>
>> On 6/26/2023 8:17 PM, Dixit, Ashutosh wrote:
>>> On Mon, 26 Jun 2023 19:12:18 -0700, Vinay Belgaumkar wrote:
>>>> GuC load takes longer sometimes due to GT frequency not ramping up.
>>>> Add perf_limit_reasons to the existing warn print to see if frequency
>>>> is being throttled.
>>>>
>>>> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
>>>> ---
>>>>    drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c | 2 ++
>>>>    1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
>>>> index 364d0d546ec8..73911536a8e7 100644
>>>> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
>>>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_fw.c
>>>> @@ -254,6 +254,8 @@ static int guc_wait_ucode(struct intel_guc *guc)
>>>> 		guc_warn(guc, "excessive init time: %lldms! [freq = %dMHz, before = %dMHz, status = 0x%08X, count = %d, ret = %d]\n",
>>>> 			 delta_ms, intel_rps_read_actual_frequency(&uncore->gt->rps),
>>>> 			 before_freq, status, count, ret);
>>>> +		guc_warn(guc, "perf limit reasons = 0x%08X\n",
>>>> +			 intel_uncore_read(uncore, intel_gt_perf_limit_reasons_reg(gt)));
>>> Maybe just add at the end of the previous guc_warn?
>> Its already too long a line. If I try adding on the next line checkpatch
>> complains about splitting double quotes.
> In these cases of long quoted lines we generally ignore checkpatch. Because
> perf limit reasons is part of the "excessive init time" message it should
> be on the same line within the square brackets. So should not be
> splitting double quotes.
>
> Another idea would be something like this:
>
> 		guc_warn(guc, "excessive init time: %lldms! [freq = %dMHz, before = %dMHz, status = 0x%08X]\n",
> 			 delta_ms, intel_rps_read_actual_frequency(&uncore->gt->rps),
> 			 before_freq, status);
> 		guc_warn(guc, "excessive init time: [count = %d, ret = %d, perf limit reasons = 0x%08X]\n",
> 			 count, ret, intel_uncore_read(uncore, intel_gt_perf_limit_reasons_reg(gt)));

ok, I will split iut based on freq and non-freq based debug.

Thanks,

Vinay.

>
> Thanks.
> --
> Ashutosh