On Wed, 23 Jan 2019 at 09:14, Ulf Hansson <ulf.hans...@linaro.org> wrote: > > On Tue, 22 Jan 2019 at 15:24, Vincent Guittot > <vincent.guit...@linaro.org> wrote: > > > > Initializing accounting_timestamp to something different from 0 during > > pm_runtime_init() doesn't make sense and put useless ordering constraint > > between > > timekeeping_init() and pm_runtime_init(). > > PM runtime should start accounting time only when it is enable and discard > > the period when disabled. > > Set accounting_timestamp to now when enabling PM runtime. > > Hmm, my first impression is that this sounds like a reasonable thing > to do. However, there are couple of more things to consider. > > 1) update_pm_runtime_accounting() is setting a new value of > dev->power.accounting_timestamp, no matter of whether runtime PM has > been enabled. That's seems wrong to me, at least from the perspective > of what we are trying to change here. So you probably needs to fix > that too.
note that whatever is done before enabling pm runtime, this will be overwritten during the enablement. I can add a clean up patch but this behavior is already there with jiffies. Or do you think that update_pm_runtime_accounting can be called before timekeeping_init() ? > > 2) I don't think you explicitly need to set > dev->power.accounting_timestamp to zero at pm_runtime_init(). Just > leave it uninitialized, as we are anyways going to initialize it > before we make use of it. yes probably > > 3) How will this change affect accounting while being system > suspended? As you know, the PM core disables and re-enables runtime PM So the time in system suspended will not be accounted > during a system suspend/resume sequence. It looks to me, that you > actually need to call update_pm_runtime_accounting() from > pm_runtime_enable|disable(), or something along those lines, as to get > the accounting correct, no? I thought that everything was already done for jiffies too. As soon as pm runtime is disable, we can't really account this time to suspended_time or active_time because we don't have control anymore I think that we don't need any additional changes for pm_runtime_enable because we just init the accounting_timestamp and there is no active or suspend runtime to account yet For pm_runtime_disable(), I thought that everything was already there otherwise it means that we already didn't account the time correctly. I will have a deeper look at that > > > > > Suggested-by: "Rafael J. Wysocki" <r...@rjwysocki.net> > > Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org> > > --- > > drivers/base/power/runtime.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c > > index fb5e2b6..7df1d05 100644 > > --- a/drivers/base/power/runtime.c > > +++ b/drivers/base/power/runtime.c > > @@ -1306,6 +1306,10 @@ void pm_runtime_enable(struct device *dev) > > > > spin_lock_irqsave(&dev->power.lock, flags); > > > > + /* About to enable runtime pm, set accounting_timestamp to now */ > > + if (dev->power.disable_depth == 1) > > + dev->power.accounting_timestamp = jiffies; > > + > > if (dev->power.disable_depth > 0) > > dev->power.disable_depth--; > > else > > @@ -1506,7 +1510,7 @@ void pm_runtime_init(struct device *dev) > > dev->power.request_pending = false; > > dev->power.request = RPM_REQ_NONE; > > dev->power.deferred_resume = false; > > - dev->power.accounting_timestamp = jiffies; > > + dev->power.accounting_timestamp = 0; > > INIT_WORK(&dev->power.work, pm_runtime_work); > > > > dev->power.timer_expires = 0; > > -- > > 2.7.4 > >
