On Friday, September 19, 2014 04:57:12 AM Amit Pundir wrote:
> From: Todd Poynor <toddpoy...@google.com>
>
> Existing timestamps in a dmesg only log suspend activities
> (e.g. filesystem syncs, freezing/unfreezing tasks etc) while the
> system has already started to enter/exit the suspend state.
>
> Sometimes it is handy to have suspend entry/exit overhead
> information while debugging suspend issues. This patch print
> markers with wall timestamps at suspend Entry and Exit in
> the kernel log. These timestamps can be used to compute how
> long the system spent in low-power suspend state plus the
> entry/exit overhead.
Don't we already have tracepoints for that?
> Cc: Pavel Machek <pa...@ucw.cz>
> Cc: Thomas Gleixner <t...@linutronix.de>
> Cc: Rafael J. Wysocki <r...@rjwysocki.net>
> Cc: Len Brown <len.br...@intel.com>
> Cc: linux...@vger.kernel.org
> Cc: Android Kernel Team <kernel-t...@android.com>
> Signed-off-by: Todd Poynor <toddpoy...@google.com>
> [Amit Pundir: Reworded the commit message]
> Signed-off-by: Amit Pundir <amit.pun...@linaro.org>
> ---
> Resending this patch assuming that it might have got lost in between merge
> window rush last time and now people might have some time to look at it.
>
> kernel/power/suspend.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index 18c6219..5390c6c 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -26,6 +26,7 @@
> #include <linux/suspend.h>
> #include <linux/syscore_ops.h>
> #include <linux/ftrace.h>
> +#include <linux/rtc.h>
> #include <trace/events/power.h>
> #include <linux/compiler.h>
>
> @@ -443,6 +444,18 @@ static int enter_state(suspend_state_t state)
> return error;
> }
>
> +static void pm_suspend_marker(char *annotation)
> +{
> + struct timespec ts;
> + struct rtc_time tm;
> +
> + getnstimeofday(&ts);
> + rtc_time_to_tm(ts.tv_sec, &tm);
> + pr_info("PM: suspend %s %d-%02d-%02d %02d:%02d:%02d.%09lu UTC\n",
> + annotation, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
> + tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
> +}
> +
> /**
> * pm_suspend - Externally visible function for suspending the system.
> * @state: System sleep state to enter.
> @@ -457,6 +470,7 @@ int pm_suspend(suspend_state_t state)
> if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
> return -EINVAL;
>
> + pm_suspend_marker("entry");
> error = enter_state(state);
> if (error) {
> suspend_stats.fail++;
> @@ -464,6 +478,7 @@ int pm_suspend(suspend_state_t state)
> } else {
> suspend_stats.success++;
> }
> + pm_suspend_marker("exit");
> return error;
> }
> EXPORT_SYMBOL(pm_suspend);
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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