linux-kernel - RE: [PATCH] power: print function name of callbacks

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Date:	Tue, 22 Sep 2015 17:33:14 +0000
From:	"Brown, Len" <len.brown@...el.com>
To:	Douglas Anderson <dianders@...omium.org>,
	"rjw@...ysocki.net" <rjw@...ysocki.net>
CC:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	"pavel@....cz" <pavel@....cz>,
	"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>
Subject: RE: [PATCH] power: print function name of callbacks

have you used analyze_suspend?
It used to parse this output, but that was abandoned
when it cut over to using ftrace directly.

https://01.org/suspendresume

cheers,
-Len


> -----Original Message-----
> From: Douglas Anderson [mailto:dianders@...omium.org]
> Sent: Tuesday, September 22, 2015 1:27 PM
> To: rjw@...ysocki.net
> Cc: Dmitry Torokhov; Douglas Anderson; pavel@....cz; Brown, Len;
> gregkh@...uxfoundation.org; linux-pm@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: [PATCH] power: print function name of callbacks
> 
> The printouts writen to the logs by suspend can be a bit opaque: it can
> be hard to track them down to the actual function called.  You might
> see:
> 
>   calling  rfkill1+ @ 19473, parent: phy0
>   call rfkill1+ returned 0 after 1 usecs
>   calling  phy0+ @ 19473, parent: mmc2:0001:1
>   call phy0+ returned 0 after 19 usecs
> 
> It's a bit hard to know what's actually happening.  Instead, it's nice
> to see:
> 
>   calling  rfkill1+ @ 15793, parent: phy0, cb: rfkill_suspend
>   call rfkill1+ returned 0 after 1 usecs
>   calling  phy0+ @ 15793, parent: mmc2:0001:1, cb: wiphy_suspend
> [cfg80211]
>   call phy0+ returned 0 after 7 usecs
> 
> That makes it very obvious what's going on.  It also has the nice side
> effect of making the suspend/resume spew a little more obvious, since
> many resume functions have the word "resume" in the name:
> 
>   calling  phy0+ @ 15793, parent: mmc2:0001:1, cb: wiphy_resume [cfg80211]
>   call phy0+ returned 0 after 12 usecs
>   calling  rfkill1+ @ 15793, parent: phy0, cb: rfkill_resume
>   call rfkill1+ returned 0 after 1 usecs
> 
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
>  drivers/base/power/main.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 1710c26..e2b1f14 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -188,14 +188,14 @@ void device_pm_move_last(struct device *dev)
>  	list_move_tail(&dev->power.entry, &dpm_list);
>  }
> 
> -static ktime_t initcall_debug_start(struct device *dev)
> +static ktime_t initcall_debug_start(struct device *dev, void *cb)
>  {
>  	ktime_t calltime = ktime_set(0, 0);
> 
>  	if (pm_print_times_enabled) {
> -		pr_info("calling  %s+ @ %i, parent: %s\n",
> +		pr_info("calling  %s+ @ %i, parent: %s, cb: %pf\n",
>  			dev_name(dev), task_pid_nr(current),
> -			dev->parent ? dev_name(dev->parent) : "none");
> +			dev->parent ? dev_name(dev->parent) : "none", cb);
>  		calltime = ktime_get();
>  	}
> 
> @@ -382,7 +382,7 @@ static int dpm_run_callback(pm_callback_t cb, struct
> device *dev,
>  	if (!cb)
>  		return 0;
> 
> -	calltime = initcall_debug_start(dev);
> +	calltime = initcall_debug_start(dev, cb);
> 
>  	pm_dev_dbg(dev, state, info);
>  	trace_device_pm_callback_start(dev, info, state.event);
> @@ -1324,7 +1324,7 @@ static int legacy_suspend(struct device *dev,
> pm_message_t state,
>  	int error;
>  	ktime_t calltime;
> 
> -	calltime = initcall_debug_start(dev);
> +	calltime = initcall_debug_start(dev, cb);
> 
>  	trace_device_pm_callback_start(dev, info, state.event);
>  	error = cb(dev, state);
> --
> 2.6.0.rc0.131.gf624c3d

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