From 6909f179ca7a73f243dca7c829facca1cc1d4ff5 Mon Sep 17 00:00:00 2001 From: "Gautham R. Shenoy" Date: Tue, 7 Apr 2020 14:17:42 +0530 Subject: [PATCH] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU On Pseries LPARs, to calculate utilization, we need to know the [S]PURR ticks when the CPUs were busy or idle. The total PURR and SPURR ticks are already exposed via the per-cpu sysfs files "purr" and "spurr". This patch adds support for exposing the idle PURR and SPURR ticks via new per-cpu sysfs files named "idle_purr" and "idle_spurr". This patch also adds helper functions to accurately read the values of idle_purr and idle_spurr especially from an interrupt context between when the interrupt has occurred between the pseries_idle_prolog() and pseries_idle_epilog(). This will ensure that the idle purr/spurr values corresponding to the latest idle period is accounted for before these values are read. Signed-off-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1586249263-14048-5-git-send-email-ego@linux.vnet.ibm.com --- arch/powerpc/include/asm/idle.h | 32 +++++++++++++ arch/powerpc/kernel/sysfs.c | 82 +++++++++++++++++++++++++++++++-- 2 files changed, 111 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/idle.h b/arch/powerpc/include/asm/idle.h index 0efb25071d87..accd1f50085a 100644 --- a/arch/powerpc/include/asm/idle.h +++ b/arch/powerpc/include/asm/idle.h @@ -57,5 +57,37 @@ static inline void pseries_idle_epilog(void) ppc64_runlatch_on(); } +static inline u64 read_this_idle_purr(void) +{ + /* + * If we are reading from an idle context, update the + * idle-purr cycles corresponding to the last idle period. + * Since the idle context is not yet over, take a fresh + * snapshot of the idle-purr. + */ + if (unlikely(get_lppaca()->idle == 1)) { + update_idle_purr_accounting(); + snapshot_purr_idle_entry(); + } + + return be64_to_cpu(get_lppaca()->wait_state_cycles); +} + +static inline u64 read_this_idle_spurr(void) +{ + /* + * If we are reading from an idle context, update the + * idle-spurr cycles corresponding to the last idle period. + * Since the idle context is not yet over, take a fresh + * snapshot of the idle-spurr. + */ + if (get_lppaca()->idle == 1) { + update_idle_spurr_accounting(); + snapshot_spurr_idle_entry(); + } + + return *this_cpu_ptr(&idle_spurr_cycles); +} + #endif /* CONFIG_PPC_PSERIES */ #endif diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 479c70680b76..571b3259697e 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include "cacheinfo.h" @@ -760,6 +761,74 @@ static void create_svm_file(void) } #endif /* CONFIG_PPC_SVM */ +#ifdef CONFIG_PPC_PSERIES +static void read_idle_purr(void *val) +{ + u64 *ret = val; + + *ret = read_this_idle_purr(); +} + +static ssize_t idle_purr_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + u64 val; + + smp_call_function_single(cpu->dev.id, read_idle_purr, &val, 1); + return sprintf(buf, "%llx\n", val); +} +static DEVICE_ATTR(idle_purr, 0400, idle_purr_show, NULL); + +static void create_idle_purr_file(struct device *s) +{ + if (firmware_has_feature(FW_FEATURE_LPAR)) + device_create_file(s, &dev_attr_idle_purr); +} + +static void remove_idle_purr_file(struct device *s) +{ + if (firmware_has_feature(FW_FEATURE_LPAR)) + device_remove_file(s, &dev_attr_idle_purr); +} + +static void read_idle_spurr(void *val) +{ + u64 *ret = val; + + *ret = read_this_idle_spurr(); +} + +static ssize_t idle_spurr_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + u64 val; + + smp_call_function_single(cpu->dev.id, read_idle_spurr, &val, 1); + return sprintf(buf, "%llx\n", val); +} +static DEVICE_ATTR(idle_spurr, 0400, idle_spurr_show, NULL); + +static void create_idle_spurr_file(struct device *s) +{ + if (firmware_has_feature(FW_FEATURE_LPAR)) + device_create_file(s, &dev_attr_idle_spurr); +} + +static void remove_idle_spurr_file(struct device *s) +{ + if (firmware_has_feature(FW_FEATURE_LPAR)) + device_remove_file(s, &dev_attr_idle_spurr); +} + +#else /* CONFIG_PPC_PSERIES */ +#define create_idle_purr_file(s) +#define remove_idle_purr_file(s) +#define create_idle_spurr_file(s) +#define remove_idle_spurr_file(s) +#endif /* CONFIG_PPC_PSERIES */ + static int register_cpu_online(unsigned int cpu) { struct cpu *c = &per_cpu(cpu_devices, cpu); @@ -823,10 +892,13 @@ static int register_cpu_online(unsigned int cpu) if (!firmware_has_feature(FW_FEATURE_LPAR)) add_write_permission_dev_attr(&dev_attr_purr); device_create_file(s, &dev_attr_purr); + create_idle_purr_file(s); } - if (cpu_has_feature(CPU_FTR_SPURR)) + if (cpu_has_feature(CPU_FTR_SPURR)) { device_create_file(s, &dev_attr_spurr); + create_idle_spurr_file(s); + } if (cpu_has_feature(CPU_FTR_DSCR)) device_create_file(s, &dev_attr_dscr); @@ -910,11 +982,15 @@ static int unregister_cpu_online(unsigned int cpu) device_remove_file(s, &dev_attr_mmcra); #endif /* CONFIG_PMU_SYSFS */ - if (cpu_has_feature(CPU_FTR_PURR)) + if (cpu_has_feature(CPU_FTR_PURR)) { device_remove_file(s, &dev_attr_purr); + remove_idle_purr_file(s); + } - if (cpu_has_feature(CPU_FTR_SPURR)) + if (cpu_has_feature(CPU_FTR_SPURR)) { device_remove_file(s, &dev_attr_spurr); + remove_idle_spurr_file(s); + } if (cpu_has_feature(CPU_FTR_DSCR)) device_remove_file(s, &dev_attr_dscr);