| Message ID | 1472242678-33700-12-git-send-email-lina.iyer@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Lina,
[auto build test WARNING on pm/linux-next]
[also build test WARNING on v4.8-rc3 next-20160825]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
[Suggest to use git(>=2.9.0) format-patch --base=<commit> (or --base=auto for convenience) to record what (public, well-known) commit your patch series was built on]
[Check https://git-scm.com/docs/git-format-patch for more information]
url: https://github.com/0day-ci/linux/commits/Lina-Iyer/PM-SoC-idle-support-using-PM-domains/20160827-042847
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: i386-randconfig-s0-201634 (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All warnings (new ones prefixed by >>):
In file included from drivers/base/power/cpu_domains.c:25:0:
include/linux/tick.h: In function 'tick_nohz_get_next_wakeup':
include/linux/tick.h:138:9: error: 'tick_next_period' undeclared (first use in this function)
return tick_next_period;
^~~~~~~~~~~~~~~~
include/linux/tick.h:138:9: note: each undeclared identifier is reported only once for each function it appears in
>> include/linux/tick.h:139:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
vim +139 include/linux/tick.h
4f86d3a8 Len Brown 2007-10-03 132
4f86d3a8 Len Brown 2007-10-03 133 return len;
4f86d3a8 Len Brown 2007-10-03 134 }
4fad5e09 Lina Iyer 2016-08-26 135
4fad5e09 Lina Iyer 2016-08-26 136 static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
4fad5e09 Lina Iyer 2016-08-26 137 {
4fad5e09 Lina Iyer 2016-08-26 @138 return tick_next_period;
4fad5e09 Lina Iyer 2016-08-26 @139 }
4fad5e09 Lina Iyer 2016-08-26 140
8083e4ad venkatesh.pallipadi@intel.com 2008-08-04 141 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
0224cf4c Arjan van de Ven 2010-05-09 142 static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
:::::: The code at line 139 was first introduced by commit
:::::: 4fad5e091fe06e14a8258812e6df31f1fbb69d7f timer: Export next wake up of a CPU
:::::: TO: Lina Iyer <lina.iyer@linaro.org>
:::::: CC: 0day robot <fengguang.wu@intel.com>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/drivers/base/power/cpu_domains.c b/drivers/base/power/cpu_domains.c index 8bf61e2..79fa4ae 100644 --- a/drivers/base/power/cpu_domains.c +++ b/drivers/base/power/cpu_domains.c @@ -17,9 +17,12 @@ #include <linux/list.h> #include <linux/of.h> #include <linux/pm_domain.h> +#include <linux/pm_qos.h> +#include <linux/pm_runtime.h> #include <linux/rculist.h> #include <linux/rcupdate.h> #include <linux/slab.h> +#include <linux/tick.h> #define CPU_PD_NAME_MAX 36 @@ -51,6 +54,81 @@ static inline struct cpu_pm_domain *to_cpu_pd(struct generic_pm_domain *d) return res; } +static bool cpu_pd_down_ok(struct dev_pm_domain *pd) +{ + struct generic_pm_domain *genpd = pd_to_genpd(pd); + struct cpu_pm_domain *cpu_pd = to_cpu_pd(genpd); + int qos_ns = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); + u64 sleep_ns; + ktime_t earliest, next_wakeup; + int cpu; + int i; + + /* Reset the last set genpd state, default to index 0 */ + genpd->state_idx = 0; + + /* We don't want to power down, if QoS is 0 */ + if (!qos_ns) + return false; + + /* + * Find the sleep time for the cluster. + * The time between now and the first wake up of any CPU that + * are in this domain hierarchy is the time available for the + * domain to be idle. + * + * We only care about the next wakeup for any online CPU in that + * cluster. Hotplug off any of the CPUs that we care about will + * wait on the genpd lock, until we are done. Any other CPU hotplug + * is not of consequence to our sleep time. + */ + earliest = ktime_set(KTIME_SEC_MAX, 0); + for_each_cpu_and(cpu, cpu_pd->cpus, cpu_online_mask) { + next_wakeup = tick_nohz_get_next_wakeup(cpu); + if (earliest.tv64 > next_wakeup.tv64) + earliest = next_wakeup; + } + + sleep_ns = ktime_to_ns(ktime_sub(earliest, ktime_get())); + if (sleep_ns <= 0) + return false; + + /* + * Find the deepest sleep state that satisfies the residency + * requirement and the QoS constraint + */ + for (i = genpd->state_count - 1; i >= 0; i--) { + u64 state_sleep_ns; + + state_sleep_ns = genpd->states[i].power_off_latency_ns + + genpd->states[i].power_on_latency_ns + + genpd->states[i].residency_ns; + + /* + * If we can't sleep to save power in the state, move on + * to the next lower idle state. + */ + if (state_sleep_ns > sleep_ns) + continue; + + /* + * We also don't want to sleep more than we should to + * gaurantee QoS. + */ + if (state_sleep_ns < (qos_ns * NSEC_PER_USEC)) + break; + } + + if (i >= 0) + genpd->state_idx = i; + + return (i >= 0); +} + +static struct dev_power_governor cpu_pd_gov = { + .power_down_ok = cpu_pd_down_ok, +}; + static int cpu_pd_power_on(struct generic_pm_domain *genpd) { struct cpu_pm_domain *pd = to_cpu_pd(genpd); @@ -172,7 +250,7 @@ struct generic_pm_domain *cpu_pd_init(struct generic_pm_domain *genpd, list_add_rcu(&pd->link, &of_cpu_pd_list); mutex_unlock(&cpu_pd_list_lock); - ret = pm_genpd_init(genpd, &simple_qos_governor, false); + ret = pm_genpd_init(genpd, &cpu_pd_gov, false); if (ret) { pr_err("Unable to initialize domain %s\n", genpd->name); goto fail;
A PM domain comprising of CPUs may be powered off when all the CPUs in the domain are powered down. Powering down a CPU domain is generally a expensive operation and therefore the power performance trade offs should be considered. The time between the last CPU powering down and the first CPU powering up in a domain, is the time available for the domain to sleep. Ideally, the sleep time of the domain should fulfill the residency requirement of the domains' idle state. To do this effectively, read the time before the wakeup of the cluster's CPUs and ensure that the domain's idle state sleep time guarantees the QoS requirements of each of the CPU, the PM QoS CPU_DMA_LATENCY and the state's residency. Signed-off-by: Lina Iyer <lina.iyer@linaro.org> --- drivers/base/power/cpu_domains.c | 80 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 79 insertions(+), 1 deletion(-)