Re: [PATCH v12 2/5] soc: qcom: Add Sleep stats driver

[Maulik Shah <mkshah@codeaurora.org>]

Hi Shawn,

On 10/21/2021 7:27 AM, Shawn Guo wrote:
> On Tue, Oct 19, 2021 at 06:16:57PM +0530, Maulik Shah wrote:
>> Hi Shawn,
>>
>> On 10/19/2021 3:17 PM, Shawn Guo wrote:
>>> On Mon, Oct 18, 2021 at 07:45:30PM +0530, Maulik Shah wrote:
>>>>>> +static void qcom_create_soc_sleep_stat_files(struct dentry *root, void __iomem *reg,
>>>>>> +					     struct stats_data *d,
>>>>>> +					     const struct stats_config *config)
>>>>>> +{
>>>>>> +	char stat_type[sizeof(u32) + 1] = {0};
>>>>>> +	size_t stats_offset = config->stats_offset;
>>>>>> +	u32 offset = 0, type;
>>>>>> +	int i, j;
>>>>>> +
>>>>>> +	/*
>>>>>> +	 * On RPM targets, stats offset location is dynamic and changes from target
>>>>>> +	 * to target and sometimes from build to build for same target.
>>>>>> +	 *
>>>>>> +	 * In such cases the dynamic address is present at 0x14 offset from base
>>>>>> +	 * address in devicetree. The last 16bits indicates the stats_offset.
>>>>>> +	 */
>>>>>> +	if (config->dynamic_offset) {
>>>>>> +		stats_offset = readl(reg + RPM_DYNAMIC_ADDR);
>>>>>> +		stats_offset &= RPM_DYNAMIC_ADDR_MASK;
>>>>>> +	}
>>>>>> +
>>>>>> +	for (i = 0; i < config->num_records; i++) {
>>>>>> +		d[i].base = reg + offset + stats_offset;
>>>>>> +
>>>>>> +		/*
>>>>>> +		 * Read the low power mode name and create debugfs file for it.
>>>>>> +		 * The names read could be of below,
>>>>>> +		 * (may change depending on low power mode supported).
>>>>>> +		 * For rpmh-sleep-stats: "aosd", "cxsd" and "ddr".
>>>>>> +		 * For rpm-sleep-stats: "vmin" and "vlow".
>>>>>
>>>>> It reports 'vmin' and 'xosd' on MSM8939, 'vmin' and 'vlow' on SDM660.
>>>>> I know that 'vmin' is VDD Minimization mode, and 'xosd' is XO Shutdown
>>>>> mode.  But I'm not sure about 'vlow' mode.  Could you share some
>>>>> information regarding what this low power mode is, and how it differs
>>>>> from 'vmin' and 'xosd'?
>>>>
>>>> vlow and xosd are same.
>>>> vmin is xosd plus voltage minimization of chip, memory rails.
>>>
>>> Thanks much for the info, Maulik!
>>>
>>> I'm running your driver on qcm2290 and trying to reach vlow mode.
>>>
>>> # cat /sys/kernel/debug/qcom_sleep_stats/vlow
>>> Count: 0
>>> Last Entered At: 0
>>> Last Exited At: 0
>>> Accumulated Duration: 0
>>> Client Votes: 0x81
>>> # echo mem > /sys/power/state
>>> [  551.446603] PM: suspend entry (s2idle)
>>> [  551.450948] Filesystems sync: 0.000 seconds
>>> [  551.462828] Freezing user space processes ... (elapsed 0.002 seconds) done.
>>> [  551.472276] OOM killer disabled.
>>> [  551.475556] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
>>> [  551.484461] printk: Suspending console(s) (use no_console_suspend to debug)
>>> [  551.561280] OOM killer enabled.
>>> [  551.564461] Restarting tasks ... done.
>>> [  551.569652] PM: suspend exit
>>> # cat /sys/kernel/debug/qcom_sleep_stats/vlow
>>> Count: 0
>>> Last Entered At: 0
>>> Last Exited At: 0
>>> Accumulated Duration: 0
>>> Client Votes: 0x818081
>>>
>>> The count doesn't increases along with suspend/resume cycle at the
>>> moment.  But as you can see, 'Client Votes' field changes.  If possible,
>>> could you shed some light on what this means?
>>
>> The count will increase only when all the subsystems (APSS/Modem,etc) are in
>> power down mode and finally RPM decides to turn off xo clock.
>>
>>>
>>> As the comparison, I'm also running the downstream 'rpm_master_stats'
>>> driver in the same kernel, and the 'xo_count' field of APSS does
>>> increase along with suspend/resume cycle.  May I ask some advices what
>>> I'm possibly missing and thus getting different result between 'vlow'
>>> and 'rpm_master_stats' report?
>>
>> The vlow is a SoC level state whereas the rpm master stats indicate
>> individual subsystem state. Since you are running suspend-resume the APSS is
>> going to sleep so you see xo_count incremented for it but for MPSS i see it
>> does not increase (modem is not entering to low power mode). similarly for
>> ADSP/CDSP it does not increment. if all of these subsystems goes to power
>> down and then there is sufficient sleep time for the SoC then you may see
>> vlow/vmin incrementing.
>>
>> Hope this clarifies.
> 
> Thanks Maulik!  It's very helpful.  I have a couple of further
> questions, if you do not mind.
> 
> 1. We can understand most of vlow/vmin output.  But could you help
>     decode 'Client Votes'?  It looks like the bits are shifting along
>     with suspend/resume cycle.
> 

Client votes are history of client votes on xo. Each byte represents xo 
clock votes from subsystems.


> 2. In the rpm_master_stats output below, I know masters (processors)
>     APSS, MPSS, ADSP and CDSP, but not really sure what TZ is.  If it's
>     TrustZone, shouldn't it covered by APSS?

Yes it indicates for Trustzone but should be covered by APSS.

Thanks,
Maulik

> 
> Thanks for sharing your insights!
> 
> Shawn
> 
>>> # cat /sys/kernel/debug/rpm_master_stats
>>> APSS
>>>           shutdown_req:0x37EA3CC74
>>>           wakeup_ind:0x0
>>>           bringup_req:0x37F041958
>>>           bringup_ack:0x37F042D54
>>>           xo_last_entered_at:0x286FF36AC
>>>           xo_last_exited_at:0x28AF94178
>>>           xo_accumulated_duration:0x3EDD55B
>>>           last_sleep_transition_duration:0x122f
>>>           last_wake_transition_duration:0x11f8
>>>           xo_count:0x1
>>>           wakeup_reason:0x0
>>>           numshutdowns:0x641
>>>           active_cores:0x1
>>>                   core0
>>> MPSS
>>>           shutdown_req:0x0
>>>           wakeup_ind:0x0
>>>           bringup_req:0x0
>>>           bringup_ack:0x0
>>>           xo_last_entered_at:0x0
>>>           xo_last_exited_at:0x0
>>>           xo_accumulated_duration:0x0
>>>           last_sleep_transition_duration:0x0
>>>           last_wake_transition_duration:0x0
>>>           xo_count:0x0
>>>           wakeup_reason:0x0
>>>           numshutdowns:0x0
>>>           active_cores:0x1
>>>                   core0
>>> ADSP
>>>           shutdown_req:0x0
>>>           wakeup_ind:0x0
>>>           bringup_req:0x0
>>>           bringup_ack:0x0
>>>           xo_last_entered_at:0x0
>>>           xo_last_exited_at:0x0
>>>           xo_accumulated_duration:0x0
>>>           last_sleep_transition_duration:0x0
>>>           last_wake_transition_duration:0x0
>>>           xo_count:0x0
>>>           wakeup_reason:0x0
>>>           numshutdowns:0x0
>>>           active_cores:0x1
>>>                   core0
>>> CDSP
>>>           shutdown_req:0x0
>>>           wakeup_ind:0x0
>>>           bringup_req:0x0
>>>           bringup_ack:0x0
>>>           xo_last_entered_at:0x0
>>>           xo_last_exited_at:0x0
>>>           xo_accumulated_duration:0x0
>>>           last_sleep_transition_duration:0x0
>>>           last_wake_transition_duration:0x0
>>>           xo_count:0x0
>>>           wakeup_reason:0x0
>>>           numshutdowns:0x0
>>>           active_cores:0x0
>>> TZ
>>>           shutdown_req:0x0
>>>           wakeup_ind:0x0
>>>           bringup_req:0x0
>>>           bringup_ack:0x0
>>>           xo_last_entered_at:0x0
>>>           xo_last_exited_at:0x0
>>>           xo_accumulated_duration:0x0
>>>           last_sleep_transition_duration:0x0
>>>           last_wake_transition_duration:0x0
>>>           xo_count:0x0
>>>           wakeup_reason:0x0
>>>           numshutdowns:0x0
>>>           active_cores:0x0

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