linux-kernel - Re: PM / Suspend: Print wall time at suspend entry and exit

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Message-ID: <5931f9cb-016f-4163-4908-6825cf84b9d3@android.com>
Date:   Mon, 5 Jun 2017 14:47:21 -0700
From:   Mark Salyzyn <salyzyn@...roid.com>
To:     Pavel Machek <pavel@....cz>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Todd Poynor <toddpoynor@...gle.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>
Subject: Re: PM / Suspend: Print wall time at suspend entry and exit

On 06/05/2017 02:18 PM, Pavel Machek wrote:
> Hi!
>
>> On Mon, Jun 5, 2017 at 9:31 PM, Mark Salyzyn <salyzyn@...roid.com> wrote:
>>> Permits power state and battery life diagnosis.
>> Which is possible even without this patch and we have tools for that
>> (analyze_suspend.py, anyone?).
>>
>> Honestly, I don't see why this change is necessary or even useful.
> I ran dmesg after resume and now I...
>
> [1019729.486249] ACPI : EC: EC stopped
> [1019729.486255] PM: Saving platform NVS memory
> [1019729.486276] Disabling non-boot CPUs ...
> [1019729.490423] smpboot: CPU 1 is now offline
> [1019729.531015] smpboot: CPU 2 is now offline
> [1019729.577742] Broke affinity for irq 16
> [1019729.577747] Broke affinity for irq 17
> [1019729.577751] Broke affinity for irq 19
> [1019729.577756] Broke affinity for irq 23
> [1019729.578771] smpboot: CPU 3 is now offline
> [1019729.604987] ACPI: Low-level resume complete
> [1019729.605052] ACPI : EC: EC started
> [1019729.605054] PM: Restoring platform NVS memory
> [1019729.605352] Suspended for 3196.166 seconds
> [1019729.605376] Enabling non-boot CPUs ...
> [1019729.631246] x86: Booting SMP configuration:
> [1019729.631249] smpboot: Booting Node 0 Processor 1 APIC 0x1
> [1019729.631496] Initializing CPU#1
> [1019729.631514] Disabled fast string operations
> [1019729.636643]  cache: parent cpu1 should not be sleeping
> [1019729.637286] CPU1 is up
>
> Aha. I missed the "suspended for 3196" message before. So I believe
> you are right; there's already enough information in the kernel logs.
>
> 									Pavel

We do not get the Suspended for messages on failure to suspend 
(interrupt wakeup), but that is a weak argument ;-/ since it is 
discoverable from context and we can count the aborted suspends 
switching the tools. The Suspended for messages are in ms which is not 
accurate enough for Android user space logs (in ns) long term continuous 
tracking of monotonic vs realtime and makes no accounting for ntp 
adjustments. Currently, post mortem data only on Android, we have no 
other way to align monotonic kernel logs with user space logs without this.

Sincerely -- Mark Salyzyn