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Commit 8d1b2d93 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent 8740f941

fs/exec.c

+1 −0
Original line number Diff line number Diff line
@@ -951,6 +951,7 @@ void set_task_comm(struct task_struct *tsk, char *buf) 
	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)

include/linux/perf_counter.h

+15 −1
Original line number Diff line number Diff line
@@ -142,8 +142,9 @@ struct perf_counter_hw_event { 
				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 */
@@ -230,6 +231,16 @@ enum perf_event_type { 
	PERF_EVENT_MMAP			= 1,

	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_mmap(unsigned long addr, unsigned long len, 
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 @@ static inline void 
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__ */

kernel/perf_counter.c

+93 −0
Original line number Diff line number Diff line
@@ -1916,6 +1916,99 @@ static void perf_counter_output(struct perf_counter *counter, 
	perf_output_end(&handle);

}



/*

 * 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(&current->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

 */