Messages in this thread |  | | Subject | Re: [PATCH v3 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver | From | Daniel Lezcano <> | Date | Mon, 5 Aug 2019 09:39:30 +0200 |
| |
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 ?
> 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 >
-- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
|  |