perf_counter: track task-comm data
Similar to the mmap data stream, add one that tracks the task COMM field,
so that the userspace reporting knows what to call a task.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090408130409.127422406@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/fs/exec.c b/fs/exec.c
index e015c0b..bf47ed0 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -951,6 +951,7 @@
task_lock(tsk);
strlcpy(tsk->comm, buf, sizeof(tsk->comm));
task_unlock(tsk);
+ perf_counter_comm(tsk);
}
int flush_old_exec(struct linux_binprm * bprm)
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 8bf764fc..a70a55f 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -142,8 +142,9 @@
exclude_idle : 1, /* don't count when idle */
mmap : 1, /* include mmap data */
munmap : 1, /* include munmap data */
+ comm : 1, /* include comm data */
- __reserved_1 : 53;
+ __reserved_1 : 52;
__u32 extra_config_len;
__u32 wakeup_events; /* wakeup every n events */
@@ -231,6 +232,16 @@
PERF_EVENT_MUNMAP = 2,
/*
+ * struct {
+ * struct perf_event_header header;
+ *
+ * u32 pid, tid;
+ * char comm[];
+ * };
+ */
+ PERF_EVENT_COMM = 3,
+
+ /*
* When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
* will be PERF_RECORD_*
*
@@ -545,6 +556,8 @@
extern void perf_counter_munmap(unsigned long addr, unsigned long len,
unsigned long pgoff, struct file *file);
+extern void perf_counter_comm(struct task_struct *tsk);
+
#define MAX_STACK_DEPTH 255
struct perf_callchain_entry {
@@ -583,6 +596,7 @@
perf_counter_munmap(unsigned long addr, unsigned long len,
unsigned long pgoff, struct file *file) { }
+static inline void perf_counter_comm(struct task_struct *tsk) { }
#endif
#endif /* __KERNEL__ */
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index bf12df6..2d4aebb 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1917,6 +1917,99 @@
}
/*
+ * comm tracking
+ */
+
+struct perf_comm_event {
+ struct task_struct *task;
+ char *comm;
+ int comm_size;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+ } event;
+};
+
+static void perf_counter_comm_output(struct perf_counter *counter,
+ struct perf_comm_event *comm_event)
+{
+ struct perf_output_handle handle;
+ int size = comm_event->event.header.size;
+ int ret = perf_output_begin(&handle, counter, size, 0, 0);
+
+ if (ret)
+ return;
+
+ perf_output_put(&handle, comm_event->event);
+ perf_output_copy(&handle, comm_event->comm,
+ comm_event->comm_size);
+ perf_output_end(&handle);
+}
+
+static int perf_counter_comm_match(struct perf_counter *counter,
+ struct perf_comm_event *comm_event)
+{
+ if (counter->hw_event.comm &&
+ comm_event->event.header.type == PERF_EVENT_COMM)
+ return 1;
+
+ return 0;
+}
+
+static void perf_counter_comm_ctx(struct perf_counter_context *ctx,
+ struct perf_comm_event *comm_event)
+{
+ struct perf_counter *counter;
+
+ if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
+ if (perf_counter_comm_match(counter, comm_event))
+ perf_counter_comm_output(counter, comm_event);
+ }
+ rcu_read_unlock();
+}
+
+static void perf_counter_comm_event(struct perf_comm_event *comm_event)
+{
+ struct perf_cpu_context *cpuctx;
+ unsigned int size;
+ char *comm = comm_event->task->comm;
+
+ size = ALIGN(strlen(comm), sizeof(u64));
+
+ comm_event->comm = comm;
+ comm_event->comm_size = size;
+
+ comm_event->event.header.size = sizeof(comm_event->event) + size;
+
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_counter_comm_ctx(&cpuctx->ctx, comm_event);
+ put_cpu_var(perf_cpu_context);
+
+ perf_counter_comm_ctx(¤t->perf_counter_ctx, comm_event);
+}
+
+void perf_counter_comm(struct task_struct *task)
+{
+ struct perf_comm_event comm_event = {
+ .task = task,
+ .event = {
+ .header = { .type = PERF_EVENT_COMM, },
+ .pid = task->group_leader->pid,
+ .tid = task->pid,
+ },
+ };
+
+ perf_counter_comm_event(&comm_event);
+}
+
+/*
* mmap tracking
*/