On 06/17/2011 10:06 AM, Benjamin Herrenschmidt wrote:
On Tue, 2011-06-07 at 22:00 +0530, Trinabh Gupta wrote:+static int snooze_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + unsigned long in_purr, out_purr; + ktime_t kt_before, kt_after; + s64 usec_delta; + + /* + * Indicate to the HV that we are idle. Now would be + * a good time to find other work to dispatch. + */ + get_lppaca()->idle = 1; + get_lppaca()->donate_dedicated_cpu = 1; + in_purr = mfspr(SPRN_PURR); + + kt_before = ktime_get_real();Don't you want to timestamp before you tell the HV that you are idle ? Or is the above stuff only polled by phyp when partition interrupts are enabled ?
Hi Ben, Yes, timestamp should be before telling HV that we are idle. Thanks
+ local_irq_enable(); + set_thread_flag(TIF_POLLING_NRFLAG); + while (!need_resched()) { + ppc64_runlatch_off(); + HMT_low(); + HMT_very_low(); + } + HMT_medium(); + clear_thread_flag(TIF_POLLING_NRFLAG); + smp_mb(); + local_irq_disable(); + + kt_after = ktime_get_real(); + usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before)); + + out_purr = mfspr(SPRN_PURR); + get_lppaca()->wait_state_cycles += out_purr - in_purr; + get_lppaca()->donate_dedicated_cpu = 0; + get_lppaca()->idle = 0; + + dev->last_residency = (int)usec_delta; + + return index; +} + +static int dedicated_cede_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + unsigned long in_purr, out_purr; + ktime_t kt_before, kt_after; + s64 usec_delta; + + /* + * Indicate to the HV that we are idle. Now would be + * a good time to find other work to dispatch. + */ + get_lppaca()->idle = 1; + get_lppaca()->donate_dedicated_cpu = 1; + in_purr = mfspr(SPRN_PURR); + + kt_before = ktime_get_real();There's a bit too much code duplication for my taste here between the two functions. Not sure if it can be helped, maybe with some inlines for the prolog/epilogue ... Looks like stuff that's easy to "fix" in one place and forget the other...
Yes, I agree that there is too much code duplication in these idle routines; will fix this. Thanks -Trinabh
+ ppc64_runlatch_off(); + HMT_medium(); + cede_processor(); + + kt_after = ktime_get_real(); + usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before)); + + out_purr = mfspr(SPRN_PURR); + get_lppaca()->wait_state_cycles += out_purr - in_purr; + get_lppaca()->donate_dedicated_cpu = 0; + get_lppaca()->idle = 0; + + dev->last_residency = (int)usec_delta; + + return index; +} + +static int shared_cede_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + unsigned long in_purr, out_purr; + ktime_t kt_before, kt_after; + s64 usec_delta; + + /* + * Indicate to the HV that we are idle. Now would be + * a good time to find other work to dispatch. + */ + get_lppaca()->idle = 1; + get_lppaca()->donate_dedicated_cpu = 1; + in_purr = mfspr(SPRN_PURR); + + kt_before = ktime_get_real(); + /* + * Yield the processor to the hypervisor. We return if + * an external interrupt occurs (which are driven prior + * to returning here) or if a prod occurs from another + * processor. When returning here, external interrupts + * are enabled. + */ + cede_processor(); + + kt_after = ktime_get_real(); + + usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before)); + + out_purr = mfspr(SPRN_PURR); + get_lppaca()->wait_state_cycles += out_purr - in_purr; + get_lppaca()->donate_dedicated_cpu = 0; + get_lppaca()->idle = 0; + + dev->last_residency = (int)usec_delta; + + return index; +} + +/* + * States for dedicated partition case. + */ +static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = { + { /* Snooze */ + .name = "snooze", + .desc = "snooze", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 0, + .target_residency = 0, + .enter =&snooze_loop }, + { /* CEDE */ + .name = "CEDE", + .desc = "CEDE", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 1, + .target_residency = 10, + .enter =&dedicated_cede_loop }, +}; + +/* + * States for shared partition case. + */ +static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { + { /* Shared Cede */ + .name = "Shared Cede", + .desc = "Shared Cede", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 0, + .target_residency = 0, + .enter =&shared_cede_loop }, +}; + +int pseries_notify_cpuidle_add_cpu(int cpu) +{ + struct cpuidle_device *dev = + per_cpu_ptr(pseries_idle_cpuidle_devices, cpu); + if (dev&& cpuidle_get_driver()) { + cpuidle_disable_device(dev); + cpuidle_enable_device(dev); + } + return 0; +} + +/* + * pseries_idle_cpuidle_driver_init() + */ +static int pseries_idle_cpuidle_driver_init(void) +{ + int cstate; + struct cpuidle_driver *drv =&pseries_idle_driver; + + drv->state_count = 0; + + for (cstate = 0; cstate< MAX_IDLE_STATE_COUNT; ++cstate) { + + if (cstate> max_cstate) + break; + + /* is the state not enabled? */ + if (cpuidle_state_table[cstate].enter == NULL) + continue; + + drv->states[drv->state_count] = /* structure copy */ + cpuidle_state_table[cstate]; + + if (cpuidle_state_table == dedicated_states) + drv->states[drv->state_count].target_residency = + __get_cpu_var(smt_snooze_delay); + + drv->state_count += 1; + } + + return 0; +} + +/* pseries_idle_devices_uninit(void) + * unregister cpuidle devices and de-allocate memory + */ +static void pseries_idle_devices_uninit(void) +{ + int i; + struct cpuidle_device *dev; + + for_each_possible_cpu(i) { + dev = per_cpu_ptr(pseries_idle_cpuidle_devices, i); + cpuidle_unregister_device(dev); + } + + free_percpu(pseries_idle_cpuidle_devices); + return; +} + +/* pseries_idle_devices_init() + * allocate, initialize and register cpuidle device + */ +static int pseries_idle_devices_init(void) +{ + int i; + struct cpuidle_driver *drv =&pseries_idle_driver; + struct cpuidle_device *dev; + + pseries_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device); + if (pseries_idle_cpuidle_devices == NULL) + return -ENOMEM; + + for_each_possible_cpu(i) { + dev = per_cpu_ptr(pseries_idle_cpuidle_devices, i); + dev->state_count = drv->state_count; + dev->cpu = i; + if (cpuidle_register_device(dev)) { + printk(KERN_DEBUG "cpuidle_register_device %d failed!\n", + i); + return -EIO; + } + } + + return 0; +} + +/* + * pseries_idle_probe() + * Choose state table for shared versus dedicated partition + */ +static int pseries_idle_probe(void) +{ + if (max_cstate == 0) { + printk(KERN_DEBUG "pseries processor idle disabled.\n"); + return -EPERM; + } + + if (!firmware_has_feature(FW_FEATURE_SPLPAR)) { + printk(KERN_DEBUG "Using default idle\n"); + return -ENODEV; + } + + if (get_lppaca()->shared_proc) + cpuidle_state_table = shared_states; + else + cpuidle_state_table = dedicated_states; + + return 0; +} + +static int __init pseries_processor_idle_init(void) +{ + int retval; + + retval = pseries_idle_probe(); + if (retval) + return retval; + + pseries_idle_cpuidle_driver_init(); + retval = cpuidle_register_driver(&pseries_idle_driver); + if (retval) { + printk(KERN_DEBUG "Registration of pseries driver failed.\n"); + return retval; + } + + retval = pseries_idle_devices_init(); + if (retval) { + pseries_idle_devices_uninit(); + cpuidle_unregister_driver(&pseries_idle_driver); + return retval; + } + + printk(KERN_DEBUG "pseries_idle_driver registered\n"); + + return 0; +} + +device_initcall(pseries_processor_idle_init); diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h index e9f6d28..7c60380 100644 --- a/arch/powerpc/platforms/pseries/pseries.h +++ b/arch/powerpc/platforms/pseries/pseries.h @@ -56,4 +56,7 @@ extern struct device_node *dlpar_configure_connector(u32); extern int dlpar_attach_node(struct device_node *); extern int dlpar_detach_node(struct device_node *); +/* Snooze Delay, pseries_idle */ +DECLARE_PER_CPU(long, smt_snooze_delay); + #endif /* _PSERIES_PSERIES_H */ diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 593acce..6893a0c 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -584,9 +584,6 @@ static int __init pSeries_probe(void) return 1; } - -DECLARE_PER_CPU(long, smt_snooze_delay); - static void pseries_dedicated_idle_sleep(void) { unsigned int cpu = smp_processor_id(); diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index fbffd7e..2e46883 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -150,6 +150,7 @@ static void __devinit smp_xics_setup_cpu(int cpu) set_cpu_current_state(cpu, CPU_STATE_ONLINE); set_default_offline_state(cpu); #endif + pseries_notify_cpuidle_add_cpu(cpu); } static int __devinit smp_pSeries_kick_cpu(int nr) _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
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