Re: [PATCH v13 5/5] powerpc/perf: Add thread imc pmu support
From: Madhavan Srinivasan
Date: Sat Jul 22 2017 - 03:14:41 EST
my bad, missed to change the authership of this patch.
From: Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx>
On Wednesday 19 July 2017 03:06 AM, Madhavan Srinivasan wrote:
Add support to register Thread In-Memory Collection pmu counters.
Patch adds thread imc specific data structures, along with memory
init functions and cpuhotplug support.
Signed-off-by: Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Hemant Kumar <hemant@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/perf/imc-pmu.c | 269 +++++++++++++++++++++++++++++++++++++++++++-
include/linux/cpuhotplug.h | 1 +
2 files changed, 266 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index cd8ba3b98d29..d9a4a7ab5281 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -34,6 +34,11 @@ static cpumask_t core_imc_cpumask;
struct imc_pmu_ref *core_imc_refc;
static struct imc_pmu *core_imc_pmu;
+//Thread imc data structs and variables
+static DEFINE_PER_CPU(u64 *, thread_imc_mem);
+static struct imc_pmu *thread_imc_pmu;
+static int thread_imc_mem_size;
+
struct imc_pmu *imc_event_to_pmu(struct perf_event *event)
{
return container_of(event->pmu, struct imc_pmu, pmu);
@@ -725,15 +730,188 @@ static int core_imc_event_init(struct perf_event *event)
return 0;
}
-static u64 * get_event_base_addr(struct perf_event *event)
+/*
+ * Allocates a page of memory for each of the online cpus, and write the
+ * physical base address of that page to the LDBAR for that cpu.
+ *
+ * LDBAR Register Layout:
+ *
+ * 0 4 8 12 16 20 24 28
+ * | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - |
+ * | | [ ] [ Counter Address [8:50]
+ * | * Mode |
+ * | * PB Scope
+ * * Enable/Disable
+ *
+ * 32 36 40 44 48 52 56 60
+ * | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - |
+ * Counter Address [8:50] ]
+ *
+ */
+static int thread_imc_mem_alloc(int cpu_id, int size)
+{
+ u64 ldbar_value, *local_mem = per_cpu(thread_imc_mem, cpu_id);
+ int phys_id = topology_physical_package_id(cpu_id);
+
+ if (!local_mem) {
+ /*
+ * This case could happen only once at start, since we dont
+ * free the memory in cpu offline path.
+ */
+ local_mem = page_address(alloc_pages_node(phys_id,
+ GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
+ get_order(size)));
+ if (!local_mem)
+ return -ENOMEM;
+
+ per_cpu(thread_imc_mem, cpu_id) = local_mem;
+ }
+
+ ldbar_value = ((u64)local_mem & THREAD_IMC_LDBAR_MASK) | THREAD_IMC_ENABLE;
+
+ mtspr(SPRN_LDBAR, ldbar_value);
+ return 0;
+}
+
+static int ppc_thread_imc_cpu_online(unsigned int cpu)
{
+ return thread_imc_mem_alloc(cpu, thread_imc_mem_size);
+}
+
+static int ppc_thread_imc_cpu_offline(unsigned int cpu)
+{
+ mtspr(SPRN_LDBAR, 0);
+ return 0;
+}
+
+static int thread_imc_cpu_init(void)
+{
+ return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
+ "perf/powerpc/imc_thread:online",
+ ppc_thread_imc_cpu_online,
+ ppc_thread_imc_cpu_offline);
+}
+
+void thread_imc_pmu_sched_task(struct perf_event_context *ctx,
+ bool sched_in)
+{
+ int core_id;
+ struct imc_pmu_ref *ref;
+
+ if (!is_core_imc_mem_inited(smp_processor_id()))
+ return;
+
+ core_id = smp_processor_id() / threads_per_core;
/*
- * Subsequent patch will add code to detect caller imc pmu
- * and return accordingly.
+ * imc pmus are enabled only when it is used.
+ * See if this is triggered for the first time.
+ * If yes, take the mutex lock and enable the counters.
+ * If not, just increment the count in ref count struct.
*/
+ ref = &core_imc_refc[core_id];
+ if (!ref)
+ return;
+
+ if (sched_in) {
+ mutex_lock(&ref->lock);
+ if (ref->refc == 0) {
+ if (opal_imc_counters_start(OPAL_IMC_COUNTERS_CORE,
+ get_hard_smp_processor_id(smp_processor_id()))) {
+ mutex_unlock(&ref->lock);
+ pr_err("thread-imc: Unable to start the counter\
+ for core %d\n", core_id);
+ return;
+ }
+ }
+ ++ref->refc;
+ mutex_unlock(&ref->lock);
+ } else {
+ mutex_lock(&ref->lock);
+ ref->refc--;
+ if (ref->refc == 0) {
+ if (opal_imc_counters_stop(OPAL_IMC_COUNTERS_CORE,
+ get_hard_smp_processor_id(smp_processor_id()))) {
+ mutex_unlock(&ref->lock);
+ pr_err("thread-imc: Unable to stop the counters\
+ for core %d\n", core_id);
+ return;
+ }
+ } else if (ref->refc < 0) {
+ ref->refc = 0;
+ }
+ mutex_unlock(&ref->lock);
+ }
+
+ return;
+}
+
+static int thread_imc_event_init(struct perf_event *event)
+{
+ u32 config = event->attr.config;
+ struct task_struct *target;
+ struct imc_pmu *pmu;
+
+ if (event->attr.type != event->pmu->type)
+ return -ENOENT;
+
+ /* Sampling not supported */
+ if (event->hw.sample_period)
+ return -EINVAL;
+
+ event->hw.idx = -1;
+ pmu = imc_event_to_pmu(event);
+
+ /* Sanity check for config offset */
+ if (((config & IMC_EVENT_OFFSET_MASK) > pmu->counter_mem_size))
+ return -EINVAL;
+
+ target = event->hw.target;
+ if (!target)
+ return -EINVAL;
+
+ event->pmu->task_ctx_nr = perf_sw_context;
+ return 0;
+}
+
+static bool is_thread_imc_pmu(struct perf_event *event)
+{
+ if (!strncmp(event->pmu->name, "thread_imc", strlen("thread_imc")))
+ return true;
+
+ return false;
+}
+
+static u64 * get_event_base_addr(struct perf_event *event)
+{
+ u64 addr;
+
+ if (is_thread_imc_pmu(event)) {
+ addr = (u64)per_cpu(thread_imc_mem, smp_processor_id());
+ return (u64 *)(addr + (event->attr.config & IMC_EVENT_OFFSET_MASK));
+ }
+
return (u64 *)event->hw.event_base;
}
+static void thread_imc_pmu_start_txn(struct pmu *pmu,
+ unsigned int txn_flags)
+{
+ if (txn_flags & ~PERF_PMU_TXN_ADD)
+ return;
+ perf_pmu_disable(pmu);
+}
+
+static void thread_imc_pmu_cancel_txn(struct pmu *pmu)
+{
+ perf_pmu_enable(pmu);
+}
+
+static int thread_imc_pmu_commit_txn(struct pmu *pmu)
+{
+ perf_pmu_enable(pmu);
+ return 0;
+}
+
static u64 imc_read_counter(struct perf_event *event)
{
u64 *addr, data;
@@ -791,6 +969,26 @@ static int imc_event_add(struct perf_event *event, int flags)
return 0;
}
+static int thread_imc_event_add(struct perf_event *event, int flags)
+{
+ if (flags & PERF_EF_START)
+ imc_event_start(event, flags);
+
+ /* Enable the sched_task to start the engine */
+ perf_sched_cb_inc(event->ctx->pmu);
+ return 0;
+}
+
+static void thread_imc_event_del(struct perf_event *event, int flags)
+{
+ /*
+ * Take a snapshot and calculate the delta and update
+ * the event counter values.
+ */
+ imc_event_update(event);
+ perf_sched_cb_dec(event->ctx->pmu);
+}
+
/* update_pmu_ops : Populate the appropriate operations for "pmu" */
static int update_pmu_ops(struct imc_pmu *pmu)
{
@@ -812,6 +1010,15 @@ static int update_pmu_ops(struct imc_pmu *pmu)
pmu->pmu.event_init = core_imc_event_init;
pmu->attr_groups[IMC_CPUMASK_ATTR] = &imc_pmu_cpumask_attr_group;
break;
+ case IMC_DOMAIN_THREAD:
+ pmu->pmu.event_init = thread_imc_event_init;
+ pmu->pmu.sched_task = thread_imc_pmu_sched_task;
+ pmu->pmu.add = thread_imc_event_add;
+ pmu->pmu.del = thread_imc_event_del;
+ pmu->pmu.start_txn = thread_imc_pmu_start_txn;
+ pmu->pmu.cancel_txn = thread_imc_pmu_cancel_txn;
+ pmu->pmu.commit_txn = thread_imc_pmu_commit_txn;
+ break;
default:
break;
}
@@ -879,6 +1086,31 @@ static void cleanup_all_core_imc_memory(void)
kfree(core_imc_refc);
}
+static void thread_imc_ldbar_disable(void *dummy)
+{
+ /*
+ * By Zeroing LDBAR, we disable thread-imc
+ * updates.
+ */
+ mtspr(SPRN_LDBAR, 0);
+}
+
+void thread_imc_disable(void)
+{
+ on_each_cpu(thread_imc_ldbar_disable, NULL, 1);
+}
+
+static void cleanup_all_thread_imc_memory(void)
+{
+ int i, order = get_order(thread_imc_mem_size);
+
+ for_each_online_cpu(i) {
+ if (per_cpu(thread_imc_mem, i))
+ free_pages((u64)per_cpu(thread_imc_mem, i), order);
+
+ }
+}
+
/*
* Common function to unregister cpu hotplug callback and
* free the memory.
@@ -905,6 +1137,12 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
cleanup_all_core_imc_memory();
}
+ /* Free thread_imc memory */
+ if (pmu_ptr->domain == IMC_DOMAIN_THREAD) {
+ cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE);
+ cleanup_all_thread_imc_memory();
+ }
+
/* Only free the attr_groups which are dynamically allocated */
kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs);
kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]);
@@ -920,7 +1158,7 @@ static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent,
int pmu_index)
{
const char *s;
- int nr_cores;
+ int nr_cores, cpu, res;
if (of_property_read_string(parent, "name", &s))
return -ENODEV;
@@ -956,6 +1194,21 @@ static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent,
core_imc_pmu = pmu_ptr;
break;
+ case IMC_DOMAIN_THREAD:
+ /* Update the pmu name */
+ pmu_ptr->pmu.name = kasprintf(GFP_KERNEL, "%s%s", s, "_imc");
+ if (!pmu_ptr->pmu.name)
+ return -ENOMEM;
+
+ thread_imc_mem_size = pmu_ptr->counter_mem_size;
+ for_each_online_cpu(cpu) {
+ res = thread_imc_mem_alloc(cpu, pmu_ptr->counter_mem_size);
+ if (res)
+ return res;
+ }
+
+ thread_imc_pmu = pmu_ptr;
+ break;
default:
return -EINVAL;
}
@@ -1014,6 +1267,14 @@ int init_imc_pmu(struct device_node *parent, struct imc_pmu *pmu_ptr, int pmu_id
}
break;
+ case IMC_DOMAIN_THREAD:
+ ret = thread_imc_cpu_init();
+ if (ret) {
+ cleanup_all_thread_imc_memory();
+ return ret;
+ }
+
+ break;
default:
return -1; /* Unknown domain */
}
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 1be505db0090..1bc7dcfbf7b3 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -141,6 +141,7 @@ enum cpuhp_state {
CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE,
+ CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
CPUHP_AP_WORKQUEUE_ONLINE,
CPUHP_AP_RCUTREE_ONLINE,
CPUHP_AP_ONLINE_DYN,