[igt-dev] [PATCH i-g-t] i915/i915_power: Measure GPU idle/busy power

[Tauro, Riana]

On 1/19/2023 9:02 AM, Dixit, Ashutosh wrote:
> On Tue, 17 Jan 2023 23:22:46 -0800, Tauro, Riana wrote:
>>
>> Hi Ashutosh
>>
> 
> Hi Riana,
> 
>> Energy measurement when idle and with workload is also a part of rc6-idle
>> test.  Why do we need new tests?
> 
> We want to be able to measure max/peak power.
> 
> rc6-idle has this:
> 
> static void bg_load()
> {
> 	...
> 		/* aim for ~1% busy */
> 
> Therefore it measures this:
> 
> [adixit at DUT1220-DG2SVC igt-gpu-tools]$ sudo ./build/tests/i915_pm_rc6_residency --r rc6-idle
> IGT-Version: 1.27-g369bb6fb0f (x86_64) (Linux: 5.15.47+ x86_64)
> Opened device: /dev/dri/card0
> Starting subtest: rc6-idle
> Starting dynamic subtest: gt0-rcs0
> Total energy used while idle: 85825.3mJ (28606.5mW)
> Total energy used for normal: 86731.6mJ (28908.6mW)
> Total energy used for boost: 86992.8mJ (28995.8mW)
> Total energy used for once: 86677.9mJ (28890.5mW)
> Dynamic subtest gt0-rcs0: SUCCESS (12.235s)
> 
> The new test measures this:
> 
> [adixit at DUT1220-DG2SVC igt-gpu-tools]$ sudo ./build/tests/i915_power
> IGT-Version: 1.27-g369bb6fb0f (x86_64) (Linux: 5.15.47+ x86_64)
> Opened device: /dev/dri/card0
> Starting subtest: gpu-idle
> Measured power: 28535.5 mW
> Subtest gpu-idle: SUCCESS (3.002s)
> Starting subtest: gpu-busy
> Measured power: 50331.9 mW
> Subtest gpu-busy: SUCCESS (3.008s)
> 
> So you can see rc6-idle basically measures idle power (28 W instead of 50
> W), not power under load.
> 
> Other tests such as gem_exec_schedule also have igt_require etc. which skip
> in all sorts of situations. That is why I was forced to write these simple
> new tests.

Hi Ashutosh

Thanks for the clarification.

Riana
> Thanks.
> --
> Ashutosh