| Message ID | 20241118114114.208964-1-kjain@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 176cda0619b6c17a553625f6e2fcbc3981ad667d |
| Headers | show |
| Series | [v2,1/4] powerpc/perf: Add perf interface to expose vpa counters | expand |
On Mon, 18 Nov 2024 17:11:11 +0530, Kajol Jain wrote: > To support performance measurement for KVM on PowerVM(KoP) > feature, PowerVM hypervisor has added couple of new software > counters in Virtual Process Area(VPA) of the partition. > > Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add > support for reading VPA counters for pseries guests") > have updated the paca fields with corresponding changes. > > [...] Applied to powerpc/next. [1/4] powerpc/perf: Add perf interface to expose vpa counters https://git.kernel.org/powerpc/c/176cda0619b6c17a553625f6e2fcbc3981ad667d [2/4] docs: ABI: sysfs-bus-event_source-devices-vpa-pmu: Document sysfs event format entries for vpa_pmu https://git.kernel.org/powerpc/c/4ae0b32ecee730a41f65eb122bbb40fda7dca34a [3/4] powerpc/kvm: Add vpa latency counters to kvm_vcpu_arch https://git.kernel.org/powerpc/c/5f0b48c6a168994cc09d02888c2d939eba2af193 [4/4] powerpc/perf: Add per-task/process monitoring to vpa_pmu driver https://git.kernel.org/powerpc/c/f26f9933e3e31b2117b804b6b8932388db88a131 cheers
On Mon, Nov 18, 2024 at 05:11:11PM +0530, Kajol Jain wrote: > To support performance measurement for KVM on PowerVM(KoP) > feature, PowerVM hypervisor has added couple of new software > counters in Virtual Process Area(VPA) of the partition. > > Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add > support for reading VPA counters for pseries guests") > have updated the paca fields with corresponding changes. > > Proposed perf interface is to expose these new software > counters for monitoring of context switch latencies and > runtime aggregate. Perf interface driver is called > "vpa_pmu" and it has dependency on KVM and perf, hence > added new config called "VPA_PMU" which depends on > "CONFIG_KVM_BOOK3S_64_HV" and "CONFIG_HV_PERF_CTRS". > Since, kvm and kvm_host are currently compiled as built-in > modules, this perf interface takes the same path and > registered as a module. > > vpa_pmu perf interface needs access to some of the kvm > functions and structures like kvmhv_get_l2_counters_status(), > hence kvm_book3s_64.h and kvm_ppc.h are included. > Below are the events added to monitor KoP: > > vpa_pmu/l1_to_l2_lat/ > vpa_pmu/l2_to_l1_lat/ > vpa_pmu/l2_runtime_agg/ > > and vpa_pmu driver supports only per-cpu monitoring with this patch. > Example usage: > > [command]# perf stat -e vpa_pmu/l1_to_l2_lat/ -a -I 1000 > 1.001017682 727,200 vpa_pmu/l1_to_l2_lat/ > 2.003540491 1,118,824 vpa_pmu/l1_to_l2_lat/ > 3.005699458 1,919,726 vpa_pmu/l1_to_l2_lat/ > 4.007827011 2,364,630 vpa_pmu/l1_to_l2_lat/ > > Signed-off-by: Kajol Jain <kjain@linux.ibm.com> > Co-developed-by: Madhavan Srinivasan <maddy@linux.ibm.com> > Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> > --- > Changelog: > > v1 -> v2 > - Rebase the patch on top of kvm typo fix patch: > https://github.com/linuxppc/linux/commit/590d2f9347f7974d7954400e5d937672fd844a8b > - Fix the config check reported by kernel test robot: > https://lore.kernel.org/oe-kbuild-all/202411171117.Eq9JtACb-lkp@intel.com/ > > arch/powerpc/include/asm/kvm_book3s_64.h | 3 + > arch/powerpc/kvm/book3s_hv.c | 19 +++ > arch/powerpc/perf/Makefile | 2 + > arch/powerpc/perf/vpa-pmu.c | 197 +++++++++++++++++++++++ > arch/powerpc/platforms/pseries/Kconfig | 14 ++ > 5 files changed, 235 insertions(+) > create mode 100644 arch/powerpc/perf/vpa-pmu.c > > diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h > index 11065313d4c1..f620e3126d68 100644 > --- a/arch/powerpc/include/asm/kvm_book3s_64.h > +++ b/arch/powerpc/include/asm/kvm_book3s_64.h > @@ -688,6 +688,9 @@ int kvmhv_counters_tracepoint_regfunc(void); > void kvmhv_counters_tracepoint_unregfunc(void); > int kvmhv_get_l2_counters_status(void); > void kvmhv_set_l2_counters_status(int cpu, bool status); > +u64 kvmhv_get_l1_to_l2_cs_time(void); > +u64 kvmhv_get_l2_to_l1_cs_time(void); > +u64 kvmhv_get_l2_runtime_agg(void); > > #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */ > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index d575f7c7ab38..e618533dfc4b 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -4153,6 +4153,7 @@ void kvmhv_set_l2_counters_status(int cpu, bool status) > else > lppaca_of(cpu).l2_counters_enable = 0; > } > +EXPORT_SYMBOL(kvmhv_set_l2_counters_status); > > int kvmhv_counters_tracepoint_regfunc(void) > { > @@ -4192,6 +4193,24 @@ static void do_trace_nested_cs_time(struct kvm_vcpu *vcpu) > *l2_runtime_agg_ptr = l2_runtime_ns; > } > > +u64 kvmhv_get_l1_to_l2_cs_time(void) > +{ > + return tb_to_ns(be64_to_cpu(get_lppaca()->l1_to_l2_cs_tb)); > +} > +EXPORT_SYMBOL(kvmhv_get_l1_to_l2_cs_time); > + > +u64 kvmhv_get_l2_to_l1_cs_time(void) > +{ > + return tb_to_ns(be64_to_cpu(get_lppaca()->l2_to_l1_cs_tb)); > +} > +EXPORT_SYMBOL(kvmhv_get_l2_to_l1_cs_time); > + > +u64 kvmhv_get_l2_runtime_agg(void) > +{ > + return tb_to_ns(be64_to_cpu(get_lppaca()->l2_runtime_tb)); > +} > +EXPORT_SYMBOL(kvmhv_get_l2_runtime_agg); > + > #else > int kvmhv_get_l2_counters_status(void) > { > diff --git a/arch/powerpc/perf/Makefile b/arch/powerpc/perf/Makefile > index 4f53d0b97539..ac2cf58d62db 100644 > --- a/arch/powerpc/perf/Makefile > +++ b/arch/powerpc/perf/Makefile > @@ -16,6 +16,8 @@ obj-$(CONFIG_FSL_EMB_PERF_EVENT_E500) += e500-pmu.o e6500-pmu.o > > obj-$(CONFIG_HV_PERF_CTRS) += hv-24x7.o hv-gpci.o hv-common.o > > +obj-$(CONFIG_VPA_PMU) += vpa-pmu.o Do we need a new config option for this? I see you need 2 dependencies for vpa_pmu, so can we do the following instead? obj-$(CONFIG_KVM_BOOK3S_64_HV) += vpa-pmu.o and then in the init func of vpa_pmu, we can add the check for HV_PERF_CTRS static int __init pseries_vpa_pmu_init(void) { <snip> if (!firmware_has_feature(FW_FEATURE_LPAR) || is_kvm_guest() || !IS_ENABLED(CONFIG_HV_PERF_CTRS)) return -ENODEV; Thoughts? > + > obj-$(CONFIG_PPC_8xx) += 8xx-pmu.o > > obj-$(CONFIG_PPC64) += $(obj64-y) > diff --git a/arch/powerpc/perf/vpa-pmu.c b/arch/powerpc/perf/vpa-pmu.c > new file mode 100644 > index 000000000000..2c785eee2f71 > --- /dev/null > +++ b/arch/powerpc/perf/vpa-pmu.c > @@ -0,0 +1,197 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Performance monitoring support for Virtual Processor Area(VPA) based counters > + * > + * Copyright (C) 2024 IBM Corporation > + */ > +#define pr_fmt(fmt) "vpa_pmu: " fmt > + > +#include <linux/module.h> > +#include <linux/perf_event.h> > +#include <asm/kvm_ppc.h> > +#include <asm/kvm_book3s_64.h> > + > +#define MODULE_VERS "1.0" > +#define MODULE_NAME "pseries_vpa_pmu" > + > +#define EVENT(_name, _code) enum{_name = _code} > + > +#define VPA_PMU_EVENT_VAR(_id) event_attr_##_id > +#define VPA_PMU_EVENT_PTR(_id) (&event_attr_##_id.attr.attr) > + > +static ssize_t vpa_pmu_events_sysfs_show(struct device *dev, > + struct device_attribute *attr, char *page) > +{ > + struct perf_pmu_events_attr *pmu_attr; > + > + pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); > + > + return sprintf(page, "event=0x%02llx\n", pmu_attr->id); > +} > + > +#define VPA_PMU_EVENT_ATTR(_name, _id) \ > + PMU_EVENT_ATTR(_name, VPA_PMU_EVENT_VAR(_id), _id, \ > + vpa_pmu_events_sysfs_show) > + > +EVENT(L1_TO_L2_CS_LAT, 0x1); > +EVENT(L2_TO_L1_CS_LAT, 0x2); > +EVENT(L2_RUNTIME_AGG, 0x3); > + > +VPA_PMU_EVENT_ATTR(l1_to_l2_lat, L1_TO_L2_CS_LAT); > +VPA_PMU_EVENT_ATTR(l2_to_l1_lat, L2_TO_L1_CS_LAT); > +VPA_PMU_EVENT_ATTR(l2_runtime_agg, L2_RUNTIME_AGG); > + > +static struct attribute *vpa_pmu_events_attr[] = { > + VPA_PMU_EVENT_PTR(L1_TO_L2_CS_LAT), > + VPA_PMU_EVENT_PTR(L2_TO_L1_CS_LAT), > + VPA_PMU_EVENT_PTR(L2_RUNTIME_AGG), > + NULL > +}; > + > +static const struct attribute_group vpa_pmu_events_group = { > + .name = "events", > + .attrs = vpa_pmu_events_attr, > +}; > + > +PMU_FORMAT_ATTR(event, "config:0-31"); > +static struct attribute *vpa_pmu_format_attr[] = { > + &format_attr_event.attr, > + NULL, > +}; > + > +static struct attribute_group vpa_pmu_format_group = { > + .name = "format", > + .attrs = vpa_pmu_format_attr, > +}; > + > +static const struct attribute_group *vpa_pmu_attr_groups[] = { > + &vpa_pmu_events_group, > + &vpa_pmu_format_group, > + NULL > +}; > + > +static int vpa_pmu_event_init(struct perf_event *event) > +{ > + if (event->attr.type != event->pmu->type) > + return -ENOENT; > + > + /* it does not support event sampling mode */ > + if (is_sampling_event(event)) > + return -EOPNOTSUPP; > + > + /* no branch sampling */ > + if (has_branch_stack(event)) > + return -EOPNOTSUPP; > + > + /* Invalid event code */ > + if ((event->attr.config <= 0) || (event->attr.config > 3)) > + return -EINVAL; > + > + return 0; > +} > + > +static unsigned long get_counter_data(struct perf_event *event) > +{ > + unsigned int config = event->attr.config; > + u64 data; > + > + switch (config) { > + case L1_TO_L2_CS_LAT: > + data = kvmhv_get_l1_to_l2_cs_time(); > + break; > + case L2_TO_L1_CS_LAT: > + data = kvmhv_get_l2_to_l1_cs_time(); > + break; > + case L2_RUNTIME_AGG: > + data = kvmhv_get_l2_runtime_agg(); > + break; > + default: > + data = 0; > + break; > + } > + > + return data; > +} > + > +static int vpa_pmu_add(struct perf_event *event, int flags) > +{ > + u64 data; > + > + kvmhv_set_l2_counters_status( > + smp_processor_id(), true); > + > + data = get_counter_data(event); > + local64_set(&event->hw.prev_count, data); > + > + return 0; > +} > + > +static void vpa_pmu_read(struct perf_event *event) > +{ > + u64 prev_data, new_data, final_data; > + > + prev_data = local64_read(&event->hw.prev_count); > + new_data = get_counter_data(event); > + final_data = new_data - prev_data; > + > + local64_add(final_data, &event->count); > +} > + > +static void vpa_pmu_del(struct perf_event *event, int flags) > +{ > + vpa_pmu_read(event); > + > + /* > + * Disable vpa counter accumulation > + */ > + kvmhv_set_l2_counters_status( > + smp_processor_id(), false); > +} > + This won't work well with the kvm_hv:kvmppc_vcpu_stats tracepoint. Consider the below scenario: 1. I start recording data with the kvmppc_vcpu_stats tracepoint (with trace-cmd) and while the data is being recorded, I start using the vpa_pmu driver as well. 2. I now stop the vpa_pmu driver. This disables the l2_counters_enable counter in lppaca. (The VPA flag can be disabled for 1 or more cpus depending on the pid/tid options specified) 3. When I hit ctrl^c on the trace-cmd capture, I see partial data with 'trace-cmd report'. To get around this, we can use the fact that the 'l2_counters_enable' flag in lppaca supports all non-zero values. So we can see if we can use that as a counter instead of just using 0/1 to enable/disable recording of data. This may need some brainstorming to get right. I see the patches have been pulled in already, but I think we need to consider the above points. Thanks, Gautam
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h index 11065313d4c1..f620e3126d68 100644 --- a/arch/powerpc/include/asm/kvm_book3s_64.h +++ b/arch/powerpc/include/asm/kvm_book3s_64.h @@ -688,6 +688,9 @@ int kvmhv_counters_tracepoint_regfunc(void); void kvmhv_counters_tracepoint_unregfunc(void); int kvmhv_get_l2_counters_status(void); void kvmhv_set_l2_counters_status(int cpu, bool status); +u64 kvmhv_get_l1_to_l2_cs_time(void); +u64 kvmhv_get_l2_to_l1_cs_time(void); +u64 kvmhv_get_l2_runtime_agg(void); #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */ diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index d575f7c7ab38..e618533dfc4b 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4153,6 +4153,7 @@ void kvmhv_set_l2_counters_status(int cpu, bool status) else lppaca_of(cpu).l2_counters_enable = 0; } +EXPORT_SYMBOL(kvmhv_set_l2_counters_status); int kvmhv_counters_tracepoint_regfunc(void) { @@ -4192,6 +4193,24 @@ static void do_trace_nested_cs_time(struct kvm_vcpu *vcpu) *l2_runtime_agg_ptr = l2_runtime_ns; } +u64 kvmhv_get_l1_to_l2_cs_time(void) +{ + return tb_to_ns(be64_to_cpu(get_lppaca()->l1_to_l2_cs_tb)); +} +EXPORT_SYMBOL(kvmhv_get_l1_to_l2_cs_time); + +u64 kvmhv_get_l2_to_l1_cs_time(void) +{ + return tb_to_ns(be64_to_cpu(get_lppaca()->l2_to_l1_cs_tb)); +} +EXPORT_SYMBOL(kvmhv_get_l2_to_l1_cs_time); + +u64 kvmhv_get_l2_runtime_agg(void) +{ + return tb_to_ns(be64_to_cpu(get_lppaca()->l2_runtime_tb)); +} +EXPORT_SYMBOL(kvmhv_get_l2_runtime_agg); + #else int kvmhv_get_l2_counters_status(void) { diff --git a/arch/powerpc/perf/Makefile b/arch/powerpc/perf/Makefile index 4f53d0b97539..ac2cf58d62db 100644 --- a/arch/powerpc/perf/Makefile +++ b/arch/powerpc/perf/Makefile @@ -16,6 +16,8 @@ obj-$(CONFIG_FSL_EMB_PERF_EVENT_E500) += e500-pmu.o e6500-pmu.o obj-$(CONFIG_HV_PERF_CTRS) += hv-24x7.o hv-gpci.o hv-common.o +obj-$(CONFIG_VPA_PMU) += vpa-pmu.o + obj-$(CONFIG_PPC_8xx) += 8xx-pmu.o obj-$(CONFIG_PPC64) += $(obj64-y) diff --git a/arch/powerpc/perf/vpa-pmu.c b/arch/powerpc/perf/vpa-pmu.c new file mode 100644 index 000000000000..2c785eee2f71 --- /dev/null +++ b/arch/powerpc/perf/vpa-pmu.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Performance monitoring support for Virtual Processor Area(VPA) based counters + * + * Copyright (C) 2024 IBM Corporation + */ +#define pr_fmt(fmt) "vpa_pmu: " fmt + +#include <linux/module.h> +#include <linux/perf_event.h> +#include <asm/kvm_ppc.h> +#include <asm/kvm_book3s_64.h> + +#define MODULE_VERS "1.0" +#define MODULE_NAME "pseries_vpa_pmu" + +#define EVENT(_name, _code) enum{_name = _code} + +#define VPA_PMU_EVENT_VAR(_id) event_attr_##_id +#define VPA_PMU_EVENT_PTR(_id) (&event_attr_##_id.attr.attr) + +static ssize_t vpa_pmu_events_sysfs_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct perf_pmu_events_attr *pmu_attr; + + pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); + + return sprintf(page, "event=0x%02llx\n", pmu_attr->id); +} + +#define VPA_PMU_EVENT_ATTR(_name, _id) \ + PMU_EVENT_ATTR(_name, VPA_PMU_EVENT_VAR(_id), _id, \ + vpa_pmu_events_sysfs_show) + +EVENT(L1_TO_L2_CS_LAT, 0x1); +EVENT(L2_TO_L1_CS_LAT, 0x2); +EVENT(L2_RUNTIME_AGG, 0x3); + +VPA_PMU_EVENT_ATTR(l1_to_l2_lat, L1_TO_L2_CS_LAT); +VPA_PMU_EVENT_ATTR(l2_to_l1_lat, L2_TO_L1_CS_LAT); +VPA_PMU_EVENT_ATTR(l2_runtime_agg, L2_RUNTIME_AGG); + +static struct attribute *vpa_pmu_events_attr[] = { + VPA_PMU_EVENT_PTR(L1_TO_L2_CS_LAT), + VPA_PMU_EVENT_PTR(L2_TO_L1_CS_LAT), + VPA_PMU_EVENT_PTR(L2_RUNTIME_AGG), + NULL +}; + +static const struct attribute_group vpa_pmu_events_group = { + .name = "events", + .attrs = vpa_pmu_events_attr, +}; + +PMU_FORMAT_ATTR(event, "config:0-31"); +static struct attribute *vpa_pmu_format_attr[] = { + &format_attr_event.attr, + NULL, +}; + +static struct attribute_group vpa_pmu_format_group = { + .name = "format", + .attrs = vpa_pmu_format_attr, +}; + +static const struct attribute_group *vpa_pmu_attr_groups[] = { + &vpa_pmu_events_group, + &vpa_pmu_format_group, + NULL +}; + +static int vpa_pmu_event_init(struct perf_event *event) +{ + if (event->attr.type != event->pmu->type) + return -ENOENT; + + /* it does not support event sampling mode */ + if (is_sampling_event(event)) + return -EOPNOTSUPP; + + /* no branch sampling */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + /* Invalid event code */ + if ((event->attr.config <= 0) || (event->attr.config > 3)) + return -EINVAL; + + return 0; +} + +static unsigned long get_counter_data(struct perf_event *event) +{ + unsigned int config = event->attr.config; + u64 data; + + switch (config) { + case L1_TO_L2_CS_LAT: + data = kvmhv_get_l1_to_l2_cs_time(); + break; + case L2_TO_L1_CS_LAT: + data = kvmhv_get_l2_to_l1_cs_time(); + break; + case L2_RUNTIME_AGG: + data = kvmhv_get_l2_runtime_agg(); + break; + default: + data = 0; + break; + } + + return data; +} + +static int vpa_pmu_add(struct perf_event *event, int flags) +{ + u64 data; + + kvmhv_set_l2_counters_status( + smp_processor_id(), true); + + data = get_counter_data(event); + local64_set(&event->hw.prev_count, data); + + return 0; +} + +static void vpa_pmu_read(struct perf_event *event) +{ + u64 prev_data, new_data, final_data; + + prev_data = local64_read(&event->hw.prev_count); + new_data = get_counter_data(event); + final_data = new_data - prev_data; + + local64_add(final_data, &event->count); +} + +static void vpa_pmu_del(struct perf_event *event, int flags) +{ + vpa_pmu_read(event); + + /* + * Disable vpa counter accumulation + */ + kvmhv_set_l2_counters_status( + smp_processor_id(), false); +} + +static struct pmu vpa_pmu = { + .task_ctx_nr = perf_sw_context, + .name = "vpa_pmu", + .event_init = vpa_pmu_event_init, + .add = vpa_pmu_add, + .del = vpa_pmu_del, + .read = vpa_pmu_read, + .attr_groups = vpa_pmu_attr_groups, + .capabilities = PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT, +}; + +static int __init pseries_vpa_pmu_init(void) +{ + + /* + * List of current Linux on Power platforms and + * this driver is supported only in PowerVM LPAR + * (L1) platform. + * + * Enabled Linux on Power Platforms + * ---------------------------------------- + * [X] PowerVM LPAR (L1) + * [ ] KVM Guest On PowerVM KoP(L2) + * [ ] Baremetal(PowerNV) + * [ ] KVM Guest On PowerNV + */ + if (!firmware_has_feature(FW_FEATURE_LPAR) || is_kvm_guest()) + return -ENODEV; + + perf_pmu_register(&vpa_pmu, vpa_pmu.name, -1); + pr_info("Virtual Processor Area PMU registered.\n"); + + return 0; +} + +static void __exit pseries_vpa_pmu_cleanup(void) +{ + perf_pmu_unregister(&vpa_pmu); + pr_info("Virtual Processor Area PMU unregistered.\n"); +} + +module_init(pseries_vpa_pmu_init); +module_exit(pseries_vpa_pmu_cleanup); +MODULE_DESCRIPTION("Perf Driver for pSeries VPA pmu counter"); +MODULE_AUTHOR("Kajol Jain <kjain@linux.ibm.com>"); +MODULE_AUTHOR("Madhavan Srinivasan <maddy@linux.ibm.com>"); +MODULE_LICENSE("GPL"); diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index afc0f6a61337..42fc66e97539 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -140,6 +140,20 @@ config HV_PERF_CTRS If unsure, select Y. +config VPA_PMU + tristate "VPA PMU events" + depends on KVM_BOOK3S_64_HV && HV_PERF_CTRS + help + Enable access to the VPA PMU counters via perf. This enables + code that support measurement for KVM on PowerVM(KoP) feature. + PAPR hypervisor has introduced three new counters in the VPA area + of LPAR CPUs for KVM L2 guest observability. Two for context switches + from host to guest and vice versa, and one counter for getting + the total time spent inside the KVM guest. This config enables code + that access these software counters via perf. + + If unsure, Select N. + config IBMVIO depends on PPC_PSERIES bool
To support performance measurement for KVM on PowerVM(KoP) feature, PowerVM hypervisor has added couple of new software counters in Virtual Process Area(VPA) of the partition. Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add support for reading VPA counters for pseries guests") have updated the paca fields with corresponding changes. Proposed perf interface is to expose these new software counters for monitoring of context switch latencies and runtime aggregate. Perf interface driver is called "vpa_pmu" and it has dependency on KVM and perf, hence added new config called "VPA_PMU" which depends on "CONFIG_KVM_BOOK3S_64_HV" and "CONFIG_HV_PERF_CTRS". Since, kvm and kvm_host are currently compiled as built-in modules, this perf interface takes the same path and registered as a module. vpa_pmu perf interface needs access to some of the kvm functions and structures like kvmhv_get_l2_counters_status(), hence kvm_book3s_64.h and kvm_ppc.h are included. Below are the events added to monitor KoP: vpa_pmu/l1_to_l2_lat/ vpa_pmu/l2_to_l1_lat/ vpa_pmu/l2_runtime_agg/ and vpa_pmu driver supports only per-cpu monitoring with this patch. Example usage: [command]# perf stat -e vpa_pmu/l1_to_l2_lat/ -a -I 1000 1.001017682 727,200 vpa_pmu/l1_to_l2_lat/ 2.003540491 1,118,824 vpa_pmu/l1_to_l2_lat/ 3.005699458 1,919,726 vpa_pmu/l1_to_l2_lat/ 4.007827011 2,364,630 vpa_pmu/l1_to_l2_lat/ Signed-off-by: Kajol Jain <kjain@linux.ibm.com> Co-developed-by: Madhavan Srinivasan <maddy@linux.ibm.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> --- Changelog: v1 -> v2 - Rebase the patch on top of kvm typo fix patch: https://github.com/linuxppc/linux/commit/590d2f9347f7974d7954400e5d937672fd844a8b - Fix the config check reported by kernel test robot: https://lore.kernel.org/oe-kbuild-all/202411171117.Eq9JtACb-lkp@intel.com/ arch/powerpc/include/asm/kvm_book3s_64.h | 3 + arch/powerpc/kvm/book3s_hv.c | 19 +++ arch/powerpc/perf/Makefile | 2 + arch/powerpc/perf/vpa-pmu.c | 197 +++++++++++++++++++++++ arch/powerpc/platforms/pseries/Kconfig | 14 ++ 5 files changed, 235 insertions(+) create mode 100644 arch/powerpc/perf/vpa-pmu.c