| Message ID | 36f9cd2d944772d8e414a8240f9ec36eaec65ebd.1481288905.git.ego@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 10/12/16 00:32, Gautham R. Shenoy wrote: > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> > > In the current code for powernv_add_idle_states, there is a lot of code > duplication while initializing an idle state in powernv_states table. > > Add an inline helper function to populate the powernv_states[] table for > a given idle state. Invoke this for populating the "Nap", "Fastsleep" > and the stop states in powernv_add_idle_states. > > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > --- > drivers/cpuidle/cpuidle-powernv.c | 85 ++++++++++++++++++++++----------------- > include/linux/cpuidle.h | 1 + > 2 files changed, 50 insertions(+), 36 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c > index 7fe442c..db18af1 100644 > --- a/drivers/cpuidle/cpuidle-powernv.c > +++ b/drivers/cpuidle/cpuidle-powernv.c > @@ -167,6 +167,24 @@ static int powernv_cpuidle_driver_init(void) > return 0; > } > > +static inline void add_powernv_state(int index, const char *name, > + unsigned int flags, > + int (*idle_fn)(struct cpuidle_device *, > + struct cpuidle_driver *, > + int), > + unsigned int target_residency, > + unsigned int exit_latency, > + u64 psscr_val) > +{ > + strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN); > + strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN); Do name and desc ever diverge? > + powernv_states[index].flags = flags; > + powernv_states[index].target_residency = target_residency; > + powernv_states[index].exit_latency = exit_latency; > + powernv_states[index].enter = idle_fn; Why not call it idle_fn instead of enter? > + stop_psscr_table[index] = psscr_val; > +} > + > static int powernv_add_idle_states(void) > { > struct device_node *power_mgt; > @@ -236,6 +254,7 @@ static int powernv_add_idle_states(void) > "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); > > for (i = 0; i < dt_idle_states; i++) { > + unsigned int exit_latency, target_residency; > /* > * If an idle state has exit latency beyond > * POWERNV_THRESHOLD_LATENCY_NS then don't use it > @@ -243,28 +262,33 @@ static int powernv_add_idle_states(void) > */ > if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) Ideally this should be called POWERNV_MAX_THRESHOLD_LATENCY_NS then > continue; > + /* > + * Firmware passes residency and latency values in ns. > + * cpuidle expects it in us. > + */ > + exit_latency = ((unsigned int)latency_ns[i]) / 1000; > + if (!rc) > + target_residency = residency_ns[i] / 1000; > + else > + target_residency = 0; Where do we get rc from? what does target_residency = 0 mean? Balbir Singh
Hi Balbir, On Tue, Dec 13, 2016 at 10:51:04PM +1100, Balbir Singh wrote: > > > On 10/12/16 00:32, Gautham R. Shenoy wrote: > > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> > > > > In the current code for powernv_add_idle_states, there is a lot of code > > duplication while initializing an idle state in powernv_states table. > > > > Add an inline helper function to populate the powernv_states[] table for > > a given idle state. Invoke this for populating the "Nap", "Fastsleep" > > and the stop states in powernv_add_idle_states. > > > > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > > --- > > drivers/cpuidle/cpuidle-powernv.c | 85 ++++++++++++++++++++++----------------- > > include/linux/cpuidle.h | 1 + > > 2 files changed, 50 insertions(+), 36 deletions(-) > > > > diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c > > index 7fe442c..db18af1 100644 > > --- a/drivers/cpuidle/cpuidle-powernv.c > > +++ b/drivers/cpuidle/cpuidle-powernv.c > > @@ -167,6 +167,24 @@ static int powernv_cpuidle_driver_init(void) > > return 0; > > } > > > > +static inline void add_powernv_state(int index, const char *name, > > + unsigned int flags, > > + int (*idle_fn)(struct cpuidle_device *, > > + struct cpuidle_driver *, > > + int), > > + unsigned int target_residency, > > + unsigned int exit_latency, > > + u64 psscr_val) > > +{ > > + strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN); > > + strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN); > > Do name and desc ever diverge? On some other architectures, like kirkwood (see drivers/cpuidle/cpuidle-kirkwood.c) they do. "desc" field is used to provide a more descriptive information regarding the idle state. On POWER, the names were self-explanatory. So, we have desc same as the name. > > > + powernv_states[index].flags = flags; > > + powernv_states[index].target_residency = target_residency; > > + powernv_states[index].exit_latency = exit_latency; > > + powernv_states[index].enter = idle_fn; > > Why not call it idle_fn instead of enter? "enter" is a field name in the generic cpuidle_state structure and powernv_states[] is an instance of that structure. > > > + stop_psscr_table[index] = psscr_val; > > +} > > + > > static int powernv_add_idle_states(void) > > { > > struct device_node *power_mgt; > > @@ -236,6 +254,7 @@ static int powernv_add_idle_states(void) > > "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); > > > > for (i = 0; i < dt_idle_states; i++) { > > + unsigned int exit_latency, target_residency; > > /* > > * If an idle state has exit latency beyond > > * POWERNV_THRESHOLD_LATENCY_NS then don't use it > > @@ -243,28 +262,33 @@ static int powernv_add_idle_states(void) > > */ > > if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) > > Ideally this should be called POWERNV_MAX_THRESHOLD_LATENCY_NS then Yes, it can be called that. But then again, we're only interested in the upper threshold in this code. I will add a comment near the macro definition. > > > continue; > > + /* > > + * Firmware passes residency and latency values in ns. > > + * cpuidle expects it in us. > > + */ > > + exit_latency = ((unsigned int)latency_ns[i]) / 1000; > > + if (!rc) > > + target_residency = residency_ns[i] / 1000; > > + else > > + target_residency = 0; > > Where do we get rc from? what does target_residency = 0 mean? The rc value comes from the of_property_read_u32_array(power_mgt, "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); just before the for-loop. This tells us whether the firmware has populated the residency information for the idle state or not. rc != 0 indicates that the firmware has not populated the value. Since the governor will pick the first idle state whose target_residency matches the predicted residency, setting target_residency = 0 implies that if any stop state is selected at all, it is the earliest state. > Balbir Singh >
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 7fe442c..db18af1 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -167,6 +167,24 @@ static int powernv_cpuidle_driver_init(void) return 0; } +static inline void add_powernv_state(int index, const char *name, + unsigned int flags, + int (*idle_fn)(struct cpuidle_device *, + struct cpuidle_driver *, + int), + unsigned int target_residency, + unsigned int exit_latency, + u64 psscr_val) +{ + strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN); + strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN); + powernv_states[index].flags = flags; + powernv_states[index].target_residency = target_residency; + powernv_states[index].exit_latency = exit_latency; + powernv_states[index].enter = idle_fn; + stop_psscr_table[index] = psscr_val; +} + static int powernv_add_idle_states(void) { struct device_node *power_mgt; @@ -236,6 +254,7 @@ static int powernv_add_idle_states(void) "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); for (i = 0; i < dt_idle_states; i++) { + unsigned int exit_latency, target_residency; /* * If an idle state has exit latency beyond * POWERNV_THRESHOLD_LATENCY_NS then don't use it @@ -243,28 +262,33 @@ static int powernv_add_idle_states(void) */ if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) continue; + /* + * Firmware passes residency and latency values in ns. + * cpuidle expects it in us. + */ + exit_latency = ((unsigned int)latency_ns[i]) / 1000; + if (!rc) + target_residency = residency_ns[i] / 1000; + else + target_residency = 0; /* - * Cpuidle accepts exit_latency and target_residency in us. - * Use default target_residency values if f/w does not expose it. + * For nap and fastsleep, use default target_residency + * values if f/w does not expose it. */ if (flags[i] & OPAL_PM_NAP_ENABLED) { + if (!rc) + target_residency = 100; /* Add NAP state */ - strcpy(powernv_states[nr_idle_states].name, "Nap"); - strcpy(powernv_states[nr_idle_states].desc, "Nap"); - powernv_states[nr_idle_states].flags = 0; - powernv_states[nr_idle_states].target_residency = 100; - powernv_states[nr_idle_states].enter = nap_loop; + add_powernv_state(nr_idle_states, "Nap", + CPUIDLE_FLAG_NONE, nap_loop, + target_residency, exit_latency, 0); } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) && !(flags[i] & OPAL_PM_TIMEBASE_STOP)) { - strncpy(powernv_states[nr_idle_states].name, - names[i], CPUIDLE_NAME_LEN); - strncpy(powernv_states[nr_idle_states].desc, - names[i], CPUIDLE_NAME_LEN); - powernv_states[nr_idle_states].flags = 0; - - powernv_states[nr_idle_states].enter = stop_loop; - stop_psscr_table[nr_idle_states] = psscr_val[i]; + add_powernv_state(nr_idle_states, names[i], + CPUIDLE_FLAG_NONE, stop_loop, + target_residency, exit_latency, + psscr_val[i]); } /* @@ -274,32 +298,21 @@ static int powernv_add_idle_states(void) #ifdef CONFIG_TICK_ONESHOT if (flags[i] & OPAL_PM_SLEEP_ENABLED || flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) { + if (!rc) + target_residency = 300000; /* Add FASTSLEEP state */ - strcpy(powernv_states[nr_idle_states].name, "FastSleep"); - strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); - powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; - powernv_states[nr_idle_states].target_residency = 300000; - powernv_states[nr_idle_states].enter = fastsleep_loop; + add_powernv_state(nr_idle_states, "FastSleep", + CPUIDLE_FLAG_TIMER_STOP, + fastsleep_loop, + target_residency, exit_latency, 0); } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) && (flags[i] & OPAL_PM_TIMEBASE_STOP)) { - strncpy(powernv_states[nr_idle_states].name, - names[i], CPUIDLE_NAME_LEN); - strncpy(powernv_states[nr_idle_states].desc, - names[i], CPUIDLE_NAME_LEN); - - powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; - powernv_states[nr_idle_states].enter = stop_loop; - stop_psscr_table[nr_idle_states] = psscr_val[i]; + add_powernv_state(nr_idle_states, names[i], + CPUIDLE_FLAG_TIMER_STOP, stop_loop, + target_residency, exit_latency, + psscr_val[i]); } #endif - powernv_states[nr_idle_states].exit_latency = - ((unsigned int)latency_ns[i]) / 1000; - - if (!rc) { - powernv_states[nr_idle_states].target_residency = - ((unsigned int)residency_ns[i]) / 1000; - } - nr_idle_states++; } out: diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index bb31373..c4e10f8 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -62,6 +62,7 @@ struct cpuidle_state { }; /* Idle State Flags */ +#define CPUIDLE_FLAG_NONE (0x00) #define CPUIDLE_FLAG_COUPLED (0x02) /* state applies to multiple cpus */ #define CPUIDLE_FLAG_TIMER_STOP (0x04) /* timer is stopped on this state */