On 05.08.19 09:39, Daniel Lezcano wrote:
> On 05/08/2019 08:53, Martin Kepplinger wrote:
>
> [ ... ]
>
>>>> +static s64 cpuidle_cooling_runtime(struct cpuidle_cooling_device
>>>> *idle_cdev)
>>>> +{
>>>> + s64 next_wakeup;
>>>> + unsigned long state = idle_cdev->state;
>>>> +
>>>> + /*
>>>> + * The function should not be called when there is no
>>>> + * mitigation because:
>>>> + * - that does not make sense
>>>> + * - we end up with a division by zero
>>>> + */
>>>> + if (!state)
>>>> + return 0;
>>>> +
>>>> + next_wakeup = (s64)((idle_cdev->idle_cycle * 100) / state) -
>>>> + idle_cdev->idle_cycle;
>>>> +
>>>> + return next_wakeup * NSEC_PER_USEC;
>>>> +}
>>>> +
>>>
>>> There is a bug in your calculation formula here when "state" becomes 100.
>>> You return 0 for the injection rate, which is the same as "rate" being 0,
>>> which is dangerous. You stop cooling when it's most necessary :)
>>>
>>> I'm not sure how much sense really being 100% idle makes, so I, when testing
>>> this, just say if (state == 100) { state = 99 }. Anyways, just don't return
>>> 0.
>>>
>>
>> oh and also, this breaks S3 suspend:
>
> What breaks the S3 suspend? The idle cooling device or the bug above ?
The idle cooling device. I have to configure it out: remove
CONFIG_CPU_IDLE_THERMAL to test suspend/resume again. Errors in the
kernel log, see below.
>
>> Aug 5 06:09:20 pureos kernel: [ 807.487887] PM: suspend entry (deep)
>> Aug 5 06:09:40 pureos kernel: [ 807.501148] Filesystems sync: 0.013
>> seconds
>> Aug 5 06:09:40 pureos kernel: [ 807.501591] Freezing user space
>> processes ... (elapsed 0.003 seconds) done.
>> Aug 5 06:09:40 pureos kernel: [ 807.504741] OOM killer disabled.
>> Aug 5 06:09:40 pureos kernel: [ 807.504744] Freezing remaining
>> freezable tasks ...
>> Aug 5 06:09:40 pureos kernel: [ 827.517712] Freezing of tasks failed
>> after 20.002 seconds (4 tasks refusing to freeze, wq_busy=0):
>> Aug 5 06:09:40 pureos kernel: [ 827.527122] thermal-idle/0 S 0
>> 161 2 0x00000028
>> Aug 5 06:09:40 pureos kernel: [ 827.527131] Call trace:
>> Aug 5 06:09:40 pureos kernel: [ 827.527148] __switch_to+0xb4/0x200
>> Aug 5 06:09:40 pureos kernel: [ 827.527156] __schedule+0x1e0/0x488
>> Aug 5 06:09:40 pureos kernel: [ 827.527162] schedule+0x38/0xc8
>> Aug 5 06:09:40 pureos kernel: [ 827.527169] smpboot_thread_fn+0x250/0x2a8
>> Aug 5 06:09:40 pureos kernel: [ 827.527176] kthread+0xf4/0x120
>> Aug 5 06:09:40 pureos kernel: [ 827.527182] ret_from_fork+0x10/0x18
>> Aug 5 06:09:40 pureos kernel: [ 827.527186] thermal-idle/1 S 0
>> 162 2 0x00000028
>> Aug 5 06:09:40 pureos kernel: [ 827.527192] Call trace:
>> Aug 5 06:09:40 pureos kernel: [ 827.527197] __switch_to+0x188/0x200
>> Aug 5 06:09:40 pureos kernel: [ 827.527203] __schedule+0x1e0/0x488
>> Aug 5 06:09:40 pureos kernel: [ 827.527208] schedule+0x38/0xc8
>> Aug 5 06:09:40 pureos kernel: [ 827.527213] smpboot_thread_fn+0x250/0x2a8
>> Aug 5 06:09:40 pureos kernel: [ 827.527218] kthread+0xf4/0x120
>> Aug 5 06:09:40 pureos kernel: [ 827.527222] ret_from_fork+0x10/0x18
>> Aug 5 06:09:40 pureos kernel: [ 827.527226] thermal-idle/2 S 0
>> 163 2 0x00000028
>> Aug 5 06:09:40 pureos kernel: [ 827.527231] Call trace:
>> Aug 5 06:09:40 pureos kernel: [ 827.527237] __switch_to+0xb4/0x200
>> Aug 5 06:09:40 pureos kernel: [ 827.527242] __schedule+0x1e0/0x488
>> Aug 5 06:09:40 pureos kernel: [ 827.527247] schedule+0x38/0xc8
>> Aug 5 06:09:40 pureos kernel: [ 827.527259] smpboot_thread_fn+0x250/0x2a8
>> Aug 5 06:09:40 pureos kernel: [ 827.527264] kthread+0xf4/0x120
>> Aug 5 06:09:40 pureos kernel: [ 827.527268] ret_from_fork+0x10/0x18
>> Aug 5 06:09:40 pureos kernel: [ 827.527272] thermal-idle/3 S 0
>> 164 2 0x00000028
>> Aug 5 06:09:40 pureos kernel: [ 827.527278] Call trace:
>> Aug 5 06:09:40 pureos kernel: [ 827.527283] __switch_to+0xb4/0x200
>> Aug 5 06:09:40 pureos kernel: [ 827.527288] __schedule+0x1e0/0x488
>> Aug 5 06:09:40 pureos kernel: [ 827.527293] schedule+0x38/0xc8
>> Aug 5 06:09:40 pureos kernel: [ 827.527298] smpboot_thread_fn+0x250/0x2a8
>> Aug 5 06:09:40 pureos kernel: [ 827.527303] kthread+0xf4/0x120
>> Aug 5 06:09:40 pureos kernel: [ 827.527308] ret_from_fork+0x10/0x18
>> Aug 5 06:09:40 pureos kernel: [ 827.527375] Restarting kernel threads
>> ... done.
>> Aug 5 06:09:40 pureos kernel: [ 827.527771] OOM killer enabled.
>> Aug 5 06:09:40 pureos kernel: [ 827.527772] Restarting tasks ... done.
>> Aug 5 06:09:40 pureos kernel: [ 827.528926] PM: suspend exit
>>
>>
>> do you know where things might go wrong here?
>>
>> thanks,
>>
>> martin
>>
>
>
