On 9/29/2022 4:14 PM, Lazar, Lijo wrote:
On 9/29/2022 7:30 PM, Sharma, Shashank wrote:
On 9/29/2022 3:37 PM, Lazar, Lijo wrote:
To be clear your understanding -
Nothing is automatic in PMFW. PMFW picks a priority based on the
actual mask sent by driver.
Assuming lower bits corresponds to highest priority -
If driver sends a mask with Bit3 and Bit 0 set, PMFW will chose
profile that corresponds to Bit0. If driver sends a mask with Bit4
Bit2 set and rest unset, PMFW will chose profile that corresponds to
Bit2. However if driver sends a mask only with a single bit set, it
chooses the profile regardless of whatever was the previous profile.
t doesn't check if the existing profile > newly requested one. That
is the behavior.
So if a job send chooses a profile that corresponds to Bit0, driver
will send that. Next time if another job chooses a profile that
corresponds to Bit1, PMFW will receive that as the new profile and
switch to that. It trusts the driver to send the proper workload mask.
Hope that gives the picture.
Thanks, my understanding is also similar, referring to the core power
switch profile function here:
amd_powerplay.c::pp_dpm_switch_power_profile()
*snip code*
hwmgr->workload_mask |= (1 << hwmgr->workload_prority[type]);
index = fls(hwmgr->workload_mask);
index = index <= Workload_Policy_Max ? index - 1 : 0;
workload = hwmgr->workload_setting[index];
*snip_code*
hwmgr->hwmgr_func->set_power_profile_mode(hwmgr, &workload, 0);
Here I can see that the new workload mask is appended into the
existing workload mask (not overwritten). So if we keep sending new
workload_modes, they would be appended into the workload flags and
finally the PM will pick the most aggressive one of all these flags,
as per its policy.
Actually it's misleading -
The path for sienna is -
set_power_profile_mode -> sienna_cichlid_set_power_profile_mode
This code here is a picking one based on lookup table.
workload_type = smu_cmn_to_asic_specific_index(smu,
CMN2ASIC_MAPPING_WORKLOAD,
smu->power_profile_mode);
This is that lookup table -
static struct cmn2asic_mapping
sienna_cichlid_workload_map[PP_SMC_POWER_PROFILE_COUNT] = {
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT,
WORKLOAD_PPLIB_DEFAULT_BIT),
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_FULLSCREEN3D,
WORKLOAD_PPLIB_FULL_SCREEN_3D_BIT),
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_POWERSAVING,
WORKLOAD_PPLIB_POWER_SAVING_BIT),
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_VIDEO,
WORKLOAD_PPLIB_VIDEO_BIT),
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_VR, WORKLOAD_PPLIB_VR_BIT),
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_COMPUTE,
WORKLOAD_PPLIB_COMPUTE_BIT),
WORKLOAD_MAP(PP_SMC_POWER_PROFILE_CUSTOM,
WORKLOAD_PPLIB_CUSTOM_BIT),
};
And this is the place of interaction with PMFW. (1 << workload_type) is
the mask being sent.
smu_cmn_send_smc_msg_with_param(smu, SMU_MSG_SetWorkloadMask,
1 << workload_type, NULL);
In the end, driver implementation expects only one bit to be set.
Well this seems like a bug here in the core functions, because the
powerplay layer is doing the right thing by appending the workload flags
keeping in mind that a profile_change can be requested while one profile
is active, but the core functions are actually ignoring those flags.
This brings us to look into actual PM FW expectations. If it expects
only one flag to be set in the power_mode change message, we don't need
to bother about this anymore. But if it can handle more than one flag
but the core driver implementation is blocking it, we will have to fix
that as well.
@Alex: How can we get more information on this ?
- Shashank
Thanks,
Lijo
Now, when we have a single workload:
-> Job1: requests profile P1 via UAPI, ref count = 1
-> driver sends flags for p1
-> PM FW applies profile P1
-> Job executes in profile P1
-> Job goes to reset function, ref_count = 0,
-> Power profile resets
Now, we have conflicts only when we see multiple workloads (Job1 and
Job 2)
-> Job1: requests profile P1 via UAPI, ref count = 1
-> driver sends flags for p1
-> PM FW applies profile P1
-> Job executes in profile P1
-> Job2: requests profile P2 via UAPI, refcount = 2
-> driver sends flags for (P1|P2)
-> PM FW picks the more aggressive of the two (Say P1, stays in P1)
-> Job1 goes to reset function, ref_count = 1, job1 does not reset
power profile
-> Job2 goes to reset function, ref_counter = 2, job 2 resets Power
profile
-> Power profile resets to None
So this state machine looks like if there is only 1 job, it will be
executed in desired mode. But if there are multiple, the most
aggressive profile will be picked, and every job will be executed in
atleast the requested power profile mode or higher.
Do you find any problem so far ?
- Shashank
Thanks,
Lijo
