Update perf counter ABI

[lttng-modules.git] / lttng-context-perf-counters.c

diff --git a/lttng-context-perf-counters.c b/lttng-context-perf-counters.c
new file mode 100644 (file)
index 0000000..e9a5788
--- /dev/null
+++ b/lttng-context-perf-counters.c
@@ -0,0 +1,160 @@
+/*
+ * (C) Copyright       2009-2011 -
+ *             Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * LTTng performance monitoring counters (perf-counters) integration module.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/perf_event.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include "ltt-events.h"
+#include "wrapper/ringbuffer/frontend_types.h"
+#include "wrapper/vmalloc.h"
+#include "ltt-tracer.h"
+
+/*
+ * TODO: Add CPU hotplug support.
+ */
+
+static DEFINE_MUTEX(perf_counter_mutex);
+static LIST_HEAD(perf_counter_contexts);
+
+static
+size_t perf_counter_get_size(size_t offset)
+{
+       size_t size = 0;
+
+       size += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));
+       size += sizeof(uint64_t);
+       return size;
+}
+
+static
+void perf_counter_record(struct lttng_ctx_field *field,
+                        struct lib_ring_buffer_ctx *ctx,
+                        struct ltt_channel *chan)
+{
+       struct perf_event *event;
+       uint64_t value;
+
+       event = field->u.perf_counter.e[ctx->cpu];
+       event->pmu->read(event);
+       value = local64_read(&event->count);
+       lib_ring_buffer_align_ctx(ctx, ltt_alignof(value));
+       chan->ops->event_write(ctx, &value, sizeof(value));
+}
+
+static
+void overflow_callback(struct perf_event *event, int nmi,
+                      struct perf_sample_data *data,
+                      struct pt_regs *regs)
+{
+}
+
+static
+void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field)
+{
+       struct perf_event **events = field->u.perf_counter.e;
+       int cpu;
+
+       mutex_lock(&perf_counter_mutex);
+       list_del(&field->u.perf_counter.head);
+       for_each_online_cpu(cpu)
+               perf_event_release_kernel(events[cpu]);
+       mutex_unlock(&perf_counter_mutex);
+       kfree(field->event_field.name);
+       kfree(field->u.perf_counter.attr);
+       kfree(events);
+}
+
+int lttng_add_perf_counter_to_ctx(uint32_t type,
+                                 uint64_t config,
+                                 const char *name,
+                                 struct lttng_ctx **ctx)
+{
+       struct lttng_ctx_field *field;
+       struct perf_event **events;
+       struct perf_event_attr *attr;
+       int ret;
+       int cpu;
+       char *name_alloc;
+
+       events = kzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL);
+       if (!events)
+               return -ENOMEM;
+
+       attr = kzalloc(sizeof(*field->u.perf_counter.attr), GFP_KERNEL);
+       if (!attr) {
+               ret = -ENOMEM;
+               goto error_attr;
+       }
+
+       attr->type = type;
+       attr->config = config;
+       attr->size = sizeof(struct perf_event_attr);
+       attr->pinned = 1;
+       attr->disabled = 0;
+
+       mutex_lock(&perf_counter_mutex);
+
+       for_each_online_cpu(cpu) {
+               events[cpu] = perf_event_create_kernel_counter(attr,
+                                       cpu, NULL, overflow_callback);
+               if (!events[cpu]) {
+                       ret = -EINVAL;
+                       goto error;
+               }
+       }
+
+       name_alloc = kstrdup(name, GFP_KERNEL);
+       if (!field->event_field.name)
+               goto name_alloc_error;
+
+       field = lttng_append_context(ctx);
+       if (!field) {
+               ret = -ENOMEM;
+               goto error;
+       }
+       field->destroy = lttng_destroy_perf_counter_field;
+
+       field->event_field.name = name_alloc;
+       field->event_field.type.atype = atype_integer;
+       field->event_field.type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+       field->event_field.type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
+       field->event_field.type.u.basic.integer.signedness = is_signed_type(unsigned long);
+       field->event_field.type.u.basic.integer.reverse_byte_order = 0;
+       field->event_field.type.u.basic.integer.base = 10;
+       field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
+       field->get_size = perf_counter_get_size;
+       field->record = perf_counter_record;
+       field->u.perf_counter.e = events;
+       field->u.perf_counter.attr = attr;
+
+       list_add(&field->u.perf_counter.head, &perf_counter_contexts);
+       mutex_unlock(&perf_counter_mutex);
+
+       wrapper_vmalloc_sync_all();
+       return 0;
+
+error:
+       kfree(name_alloc);
+name_alloc_error:
+       for_each_online_cpu(cpu) {
+               if (events[cpu])
+                       perf_event_release_kernel(events[cpu]);
+       }
+       mutex_unlock(&perf_counter_mutex);
+       kfree(attr);
+error_attr:
+       kfree(events);
+       return ret;
+}
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support");