linux-kernel - Re: [PATCH v2] power: Include additional information in pm_print

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Date:	Mon, 17 Jun 2013 15:06:41 +0000
From:	Shuah Khan <shuah.kh@...sung.com>
To:	Joe Perches <joe@...ches.com>
Cc:	"pavel@....cz" <pavel@....cz>, "rjw@...k.pl" <rjw@...k.pl>,
	"len.brown@...el.com" <len.brown@...el.com>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"shuahkhan@...il.com" <shuahkhan@...il.com>,
	Shuah Khan <shuah.kh@...sung.com>
Subject: Re: [PATCH v2] power: Include additional information in pm_print_times

On 06/14/2013 02:55 PM, Joe Perches wrote:
> On Fri, 2013-06-14 at 14:35 -0600, Shuah Khan wrote:
>> Change __device_suspend() path to include driver name and the ops that
>> get run for a device. This additional information helps associate the
>> driver and the type of pm_ops the device uses in the suspend path very
>> quickly which will aid in debugging problems in suspend and resume paths.
>> Changed both start and end debug messages to include pm_ops information
>> and use dev_info() instead of pr_info().
>>
>> dmesg output before the change:
>>
>> [  164.390032] calling  1-1+ @ 69, parent: usb1
>> [  164.390035] call 1-1+ returned 0 after 0 usecs
>
>> dmesg output after the change:
>>
>> [   58.707002] usb usb1: calling type pm ops @ 57, parent: 0000:00:1d.0
>> [   58.707641] usb usb1: call type pm ops returned 0 after 611 usecs
>
>> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> []
>> +static ktime_t initcall_debug_start(struct device *dev, char *info)
> []
>> +		/* string in info has an extra space at the end */
>> +		dev_info(dev, "calling %s@ %i, parent: %s\n",
>> +			info, task_pid_nr(current),
>>   			dev->parent ? dev_name(dev->parent) : "none");
>
>>   static void initcall_debug_report(struct device *dev, ktime_t calltime,
> []
>> -		pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
>> +		/* string in info has an extra space at the end */
>> +		dev_info(dev, "call %sreturned %d after %llu usecs\n", info,
>>   			error, (unsigned long long)ktime_to_ns(delta) >> 10);
>
> Perhaps align the "calling and "call" and include
> task_pid_nr(current)?
>
> [   58.707002] usb usb1: calling type pm ops @ 57, parent: 0000:00:1d.0
> [   58.707641] usb usb1: call type pm ops returned 0 after 611 usecs
>
> so it's:
>
> [   58.707002] usb usb1: enter 'type pm ops' @ 57, parent: 0000:00:1d.0
> [   58.707641] usb usb1: exit  'type pm ops' @ 57, parent: 0000:00:1d.0, error: 0 (611 usecs)
>
> or:
>
> [   58.707002] usb usb1: enter 'type pm ops' @ 57, parent: 0000:00:1d.0
> [   58.707641] usb usb1: exit  'type pm ops' @ 57, error:  0 (611 usecs)
>
>
>

Including parent id and task id in the debug_report makes sense to have 
a tighter association between start and end messages. Let me re-work it 
and send another revision of the patch. I will use Start/end or 
Begin/end pairing.

thanks,
-- Shuah

Shuah Khan, Linux Kernel Developer - Open Source Group Samsung Research 
America (Silicon Valley) shuah.kh@...sung.com | (970) 672-0658
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