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From: Ravi Chandra Sadineni <ravisadineni@google.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ravi Chandra Sadineni <ravisadineni@chromium.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	chenhong3@huawei.com, Pavel Machek <pavel@ucw.cz>,
	Dmitry Torokhov <dtor@google.com>,
	Len Brown <len.brown@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Todd Broch <tbroch@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Rajat Jain <rajatja@google.com>, Benson Leung <bleung@google.com>
Subject: Re: [PATCH] power: Print wakeup_count instead of event_count in the sysfs attribute.
Date: Sun, 3 Jun 2018 10:14:09 -0700	[thread overview]
Message-ID: <CAOGSYL0ga-H=0a5EEDmOWSZjnmG1Qc=9AxAbM_-ifHDj_FbREg@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0gWeq034sObmHsbJoiBri4a=Av8xroeuW+eqyv_W=cHjQ@mail.gmail.com>

Hi Rafael,

On Sun, Jun 3, 2018 at 1:05 AM, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Sat, Jun 2, 2018 at 4:32 AM, Ravi Chandra Sadineni
> <ravisadineni@chromium.org> wrote:
>> Currently we show event_count instead of wakeup_count as part of per
>> device wakeup_count sysfs attribute. Change it to wakeup_count to make
>> it more meaningful.
>
> More information, please.
>
> In particular, why it is more meaningful.
Wakeup_count increments only when events_check_enabled is set. This
bool is set whenever we write current wakeup count to
/sys/power/wakeup_count from the user land. Also events_check_enabled
is cleared on every resume. My understanding is that, userland is
expected to write to this just before suspend. This way
pm_wakeup_event() when called from irqs will increment the
wakeup_count only if we are in system wide suspend resume cycle and
should give a fair approximation of how many times a device might have
caused a wake from S3/S0iX.  event_count on the other hand will
increment every time pm_wakeup_event() is called irrespective of
whether we are in a suspend/resume cycle.  For example when I try
doing something like this (https://lkml.org/lkml/2018/6/1/890), we see
the wakeup_count sysfs attribute for the particular device
incrementing every time there is a irq. If it is important to expose
event_count via sysfs attribute, should we create another attribute ?
Also we do expose each of these counters via
debugfs(/sys/kernel/debug/wake_sources).

Please correct me if I am wrong or missing something. Also if there is
a better way to do this, please let me know.
>
> Thanks,
> Rafael

  reply	other threads:[~2018-06-03 17:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-02  2:32 Ravi Chandra Sadineni
2018-06-02 19:02 ` Pavel Machek
2018-06-03  8:05 ` Rafael J. Wysocki
2018-06-03 17:14   ` Ravi Chandra Sadineni [this message]
2018-06-07 16:47     ` Ravi Chandra Sadineni
2018-06-08  9:16       ` Rafael J. Wysocki

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