Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 437f24fb authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

ftrace: add cpu annotation for function graph tracer 



Impact: enhancement for function graph tracer

When run on a SMP box, the function graph tracer is confusing because
it shows the different CPUS as changes in the trace.

This patch adds the annotation of 'CPU[###]' where ### is a three digit
number. The output will look similar to this:

CPU[001]     dput() {
CPU[000] } 726
CPU[001]     } 487
CPU[000] do_softirq() {
CPU[001]   } 2221
CPU[000]   __do_softirq() {
CPU[000]     __local_bh_disable() {
CPU[001]   unroll_tree_refs() {
CPU[000]     } 569
CPU[001]   } 501
CPU[000]     rcu_process_callbacks() {
CPU[001]   kfree() {

What makes this nice is that now you can grep the file and produce
readable format for a particular CPU.

 # cat /debug/tracing/trace > /tmp/trace
 # grep '^CPU\[000\]' /tmp/trace > /tmp/trace0
 # grep '^CPU\[001\]' /tmp/trace > /tmp/trace1

Will give you:

 # head /tmp/trace0
CPU[000] ------------8<---------- thread sshd-3899 ------------8<----------
CPU[000]     inotify_dentry_parent_queue_event() {
CPU[000]     } 2531
CPU[000]     inotify_inode_queue_event() {
CPU[000]     } 505
CPU[000]   } 69626
CPU[000] } 73089
CPU[000] audit_syscall_exit() {
CPU[000]   path_put() {
CPU[000]     dput() {

 # head /tmp/trace1
CPU[001] ------------8<---------- thread pcscd-3446 ------------8<----------
CPU[001]               } 4186
CPU[001]               dput() {
CPU[001]               } 543
CPU[001]               vfs_permission() {
CPU[001]                 inode_permission() {
CPU[001]                   shmem_permission() {
CPU[001]                     generic_permission() {
CPU[001]                     } 501
CPU[001]                   } 2205

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 660c7f9b

kernel/trace/trace_functions_graph.c

+22 −12
Original line number Original line Diff line number Diff line
@@ -28,7 +28,7 @@ static struct tracer_flags tracer_flags = { 
};

};





/* pid on the last trace processed */

/* pid on the last trace processed */

static pid_t last_pid = -1;

static pid_t last_pid[NR_CPUS] = { [0 ... NR_CPUS-1] = -1 };





static int graph_trace_init(struct trace_array *tr)

static int graph_trace_init(struct trace_array *tr)

{

{
@@ -53,29 +53,34 @@ static void graph_trace_reset(struct trace_array *tr) 
}

}





/* If the pid changed since the last trace, output this event */

/* If the pid changed since the last trace, output this event */

static int verif_pid(struct trace_seq *s, pid_t pid)

static int verif_pid(struct trace_seq *s, pid_t pid, int cpu)

{

{

	char *comm;

	char *comm;





	if (last_pid != -1 && last_pid == pid)

	if (last_pid[cpu] != -1 && last_pid[cpu] == pid)

		return 1;

		return 1;





	last_pid = pid;

	last_pid[cpu] = pid;

	comm = trace_find_cmdline(pid);

	comm = trace_find_cmdline(pid);





	return trace_seq_printf(s, "\n------------8<---------- thread %s-%d"

	return trace_seq_printf(s, "\nCPU[%03d]"

				    " ------------8<---------- thread %s-%d"

				    " ------------8<----------\n\n",

				    " ------------8<----------\n\n",

				    comm, pid);

				    cpu, comm, pid);

}

}





static enum print_line_t

static enum print_line_t

print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,

print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,

		struct trace_entry *ent)

		  struct trace_entry *ent, int cpu)

{

{

	int i;

	int i;

	int ret;

	int ret;





	if (!verif_pid(s, ent->pid))

	if (!verif_pid(s, ent->pid, cpu))

		return TRACE_TYPE_PARTIAL_LINE;



	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {

	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
@@ -96,12 +101,16 @@ print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s, 




static enum print_line_t

static enum print_line_t

print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,

print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,

		   struct trace_entry *ent)

		   struct trace_entry *ent, int cpu)

{

{

	int i;

	int i;

	int ret;

	int ret;





	if (!verif_pid(s, ent->pid))

	if (!verif_pid(s, ent->pid, cpu))

		return TRACE_TYPE_PARTIAL_LINE;



	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {

	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
@@ -137,12 +146,13 @@ print_graph_function(struct trace_iterator *iter) 
	case TRACE_GRAPH_ENT: {

	case TRACE_GRAPH_ENT: {

		struct ftrace_graph_ent_entry *field;

		struct ftrace_graph_ent_entry *field;

		trace_assign_type(field, entry);

		trace_assign_type(field, entry);

		return print_graph_entry(&field->graph_ent, s, entry);

		return print_graph_entry(&field->graph_ent, s, entry,

					 iter->cpu);

	}

	}

	case TRACE_GRAPH_RET: {

	case TRACE_GRAPH_RET: {

		struct ftrace_graph_ret_entry *field;

		struct ftrace_graph_ret_entry *field;

		trace_assign_type(field, entry);

		trace_assign_type(field, entry);

		return print_graph_return(&field->ret, s, entry);

		return print_graph_return(&field->ret, s, entry, iter->cpu);

	}

	}

	default:

	default:

		return TRACE_TYPE_UNHANDLED;

		return TRACE_TYPE_UNHANDLED;