From: Martin Kepplinger <martin.kepplinger@puri.sm>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
viresh.kumar@linaro.org, kevin.wangtao@linaro.org,
leo.yan@linaro.org, edubezval@gmail.com,
vincent.guittot@linaro.org, javi.merino@kernel.org,
rui.zhang@intel.com, daniel.thompson@linaro.org
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver
Date: Mon, 5 Aug 2019 09:42:38 +0200 [thread overview]
Message-ID: <172fc66f-a385-1d58-91f1-60224fac348b@puri.sm> (raw)
In-Reply-To: <421c43a9-c721-05eb-1860-dfb5c042bc95@linaro.org>
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
>>
>
>
next prev parent reply other threads:[~2019-08-05 7:42 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-05 16:16 [PATCH v3 0/7] CPU cooling device new strategies Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 1/7] thermal/drivers/cpu_cooling: Fixup the header and copyright Daniel Lezcano
2018-04-11 6:15 ` Viresh Kumar
2018-04-11 8:56 ` Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 2/7] thermal/drivers/cpu_cooling: Add Software Package Data Exchange (SPDX) Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 3/7] thermal/drivers/cpu_cooling: Remove pointless field Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 4/7] thermal/drivers/Kconfig: Convert the CPU cooling device to a choice Daniel Lezcano
2018-04-11 6:18 ` Viresh Kumar
2018-04-11 8:58 ` Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 5/7] thermal/drivers/cpu_cooling: Add idle cooling device documentation Daniel Lezcano
2018-04-05 16:16 ` [PATCH v3 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver Daniel Lezcano
2018-04-11 8:51 ` Viresh Kumar
2018-04-11 9:29 ` Daniel Lezcano
2018-04-13 11:23 ` Sudeep Holla
2018-04-13 11:47 ` Daniel Lezcano
2018-04-16 7:37 ` Viresh Kumar
2018-04-16 7:44 ` Daniel Lezcano
2018-04-16 9:34 ` Sudeep Holla
2018-04-16 9:37 ` Viresh Kumar
2018-04-16 9:45 ` Daniel Lezcano
2018-04-16 9:50 ` Viresh Kumar
2018-04-16 10:03 ` Daniel Lezcano
2018-04-16 10:10 ` Viresh Kumar
2018-04-16 12:10 ` Daniel Lezcano
2018-04-16 12:30 ` Lorenzo Pieralisi
2018-04-16 13:57 ` Daniel Lezcano
2018-04-16 14:22 ` Lorenzo Pieralisi
2018-04-17 7:17 ` Daniel Lezcano
2018-04-17 10:24 ` Lorenzo Pieralisi
2018-04-16 12:31 ` Sudeep Holla
2018-04-16 12:49 ` Daniel Lezcano
2018-04-16 13:03 ` Sudeep Holla
2018-04-16 12:29 ` Sudeep Holla
2018-04-13 11:38 ` Daniel Thompson
2018-04-13 11:46 ` Daniel Lezcano
2019-08-05 5:11 ` Martin Kepplinger
2019-08-05 6:53 ` Martin Kepplinger
2019-08-05 7:39 ` Daniel Lezcano
2019-08-05 7:42 ` Martin Kepplinger [this message]
2019-08-05 7:58 ` Daniel Lezcano
2019-10-25 11:22 ` Martin Kepplinger
2019-10-25 14:45 ` Daniel Lezcano
2019-10-26 18:23 ` Martin Kepplinger
2019-10-28 15:16 ` Daniel Lezcano
2019-08-05 7:37 ` Daniel Lezcano
2019-08-05 7:40 ` Martin Kepplinger
2018-04-05 16:16 ` [PATCH v3 7/7] cpuidle/drivers/cpuidle-arm: Register the cooling device Daniel Lezcano
2018-04-11 8:51 ` Viresh Kumar
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