| Message ID | 1616484011-26702-4-git-send-email-aisheng.dong@nxp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Chanwoo Choi |
| Headers | show |
| Series | PM / devfreq: a few small fixes and improvements | expand |
On 21. 3. 23. 오후 4:20, Dong Aisheng wrote: > It's unnecessary to set the same freq again and run notifier calls. > > Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> > --- > drivers/devfreq/devfreq.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 85927bd7ee76..a6ee91dd17bd 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -352,13 +352,16 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, > { > struct devfreq_freqs freqs; > unsigned long cur_freq; > - int err = 0; > + int err; > > if (devfreq->profile->get_cur_freq) > devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); > else > cur_freq = devfreq->previous_freq; > > + if (new_freq == cur_freq) > + return 0; cur_freq is one of the OPP frequencies. But, new_freq is calculated from governor algorithm. It means that new_freq is not one of the frequencies. Actually, it is not efficient. After devfreq->profile->target() which almost uses devfreq_recommended_opp(), new_freq is one of OPP frequencies. > + > freqs.old = cur_freq; > freqs.new = new_freq; > devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); > @@ -375,7 +378,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, > * and DEVFREQ_POSTCHANGE because for showing the correct frequency > * change order of between devfreq device and passive devfreq device. > */ > - if (trace_devfreq_frequency_enabled() && new_freq != cur_freq) > + if (trace_devfreq_frequency_enabled()) > trace_devfreq_frequency(devfreq, new_freq, cur_freq); > > freqs.new = new_freq; > @@ -390,7 +393,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, > if (devfreq->suspend_freq) > devfreq->resume_freq = new_freq; > > - return err; > + return 0; > } > > /** >
On Tue, Mar 23, 2021 at 11:01 PM Chanwoo Choi <cwchoi00@gmail.com> wrote: > > On 21. 3. 23. 오후 4:20, Dong Aisheng wrote: > > It's unnecessary to set the same freq again and run notifier calls. > > > > Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> > > --- > > drivers/devfreq/devfreq.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > > index 85927bd7ee76..a6ee91dd17bd 100644 > > --- a/drivers/devfreq/devfreq.c > > +++ b/drivers/devfreq/devfreq.c > > @@ -352,13 +352,16 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, > > { > > struct devfreq_freqs freqs; > > unsigned long cur_freq; > > - int err = 0; > > + int err; > > > > if (devfreq->profile->get_cur_freq) > > devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); > > else > > cur_freq = devfreq->previous_freq; > > > > + if (new_freq == cur_freq) > > + return 0; > > cur_freq is one of the OPP frequencies. But, new_freq is calculated from > governor algorithm. It means that new_freq is not one of the > frequencies. Actually, it is not efficient. > > After devfreq->profile->target() which almost uses > devfreq_recommended_opp(), new_freq is one of OPP frequencies. > Yes, but i feel at least when the desired new_freq is equal to cur_freq which is the last successfully set rate, it is sufficient to bail out early as it's meaningless to re-set the same rate as the last one and notify the an unchanged rate transition in HW. Does that make sense? Regards Aisheng > > + > > freqs.old = cur_freq; > > freqs.new = new_freq; > > devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); > > @@ -375,7 +378,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, > > * and DEVFREQ_POSTCHANGE because for showing the correct frequency > > * change order of between devfreq device and passive devfreq device. > > */ > > - if (trace_devfreq_frequency_enabled() && new_freq != cur_freq) > > + if (trace_devfreq_frequency_enabled()) > > trace_devfreq_frequency(devfreq, new_freq, cur_freq); > > > > freqs.new = new_freq; > > @@ -390,7 +393,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, > > if (devfreq->suspend_freq) > > devfreq->resume_freq = new_freq; > > > > - return err; > > + return 0; > > } > > > > /** > > > > > -- > Best Regards, > Samsung Electronics > Chanwoo Choi
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 85927bd7ee76..a6ee91dd17bd 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -352,13 +352,16 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, { struct devfreq_freqs freqs; unsigned long cur_freq; - int err = 0; + int err; if (devfreq->profile->get_cur_freq) devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); else cur_freq = devfreq->previous_freq; + if (new_freq == cur_freq) + return 0; + freqs.old = cur_freq; freqs.new = new_freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); @@ -375,7 +378,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, * and DEVFREQ_POSTCHANGE because for showing the correct frequency * change order of between devfreq device and passive devfreq device. */ - if (trace_devfreq_frequency_enabled() && new_freq != cur_freq) + if (trace_devfreq_frequency_enabled()) trace_devfreq_frequency(devfreq, new_freq, cur_freq); freqs.new = new_freq; @@ -390,7 +393,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, if (devfreq->suspend_freq) devfreq->resume_freq = new_freq; - return err; + return 0; } /**
It's unnecessary to set the same freq again and run notifier calls. Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> --- drivers/devfreq/devfreq.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)