Commit 1a056155 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar

tracing/function-graph-tracer: adjustments of the trace informations

Impact: increase the visual qualities of the call-graph-tracer output

This patch applies various trace output formatting changes:

 - CPU is now a decimal number, followed by a parenthesis.

 - Overhead is now on the second column (gives a good visibility)

 - Cost is now on the third column, can't exceed 9999.99 us. It is
   followed by a virtual line based on a "|" character.

 - Functions calls are now the last column on the right. This way, we
   haven't dynamic column (which flow is harder to follow) on its right.

 - CPU and Overhead have their own option flag. They are default-on but you
   can disable them easily:

      echo nofuncgraph-cpu > trace_options
      echo nofuncgraph-overhead > trace_options

TODO:

_ Refactoring of the thread switch output.
_ Give a default-off option to output the thread and its pid on each row.
_ Provide headers
_ ....

Here is an example of the new trace style:

0)           |             mutex_unlock() {
0)      0.639 us |           __mutex_unlock_slowpath();
0)      1.607 us |         }
0)           |             remove_wait_queue() {
0)      0.616 us |           _spin_lock_irqsave();
0)      0.616 us |           _spin_unlock_irqrestore();
0)      2.779 us |         }
0)      0.495 us |         n_tty_set_room();
0) ! 9999.999 us |       }
0)           |           tty_ldisc_deref() {
0)      0.615 us |         _spin_lock_irqsave();
0)      0.616 us |         _spin_unlock_irqrestore();
0)      2.793 us |       }
0)           |           current_fs_time() {
0)      0.488 us |         current_kernel_time();
0)      0.495 us |         timespec_trunc();
0)      2.486 us |       }
0) ! 9999.999 us |     }
0) ! 9999.999 us |   }
0) ! 9999.999 us | }
0)           |     sys_read() {
0)      0.796 us |   fget_light();
0)           |       vfs_read() {
0)           |         rw_verify_area() {
0)           |           security_file_permission() {
0)      0.488 us |         cap_file_permission();
0)      1.720 us |       }
0)      3.  4 us |     }
0)           |         tty_read() {
0)      0.488 us |       tty_paranoia_check();
0)           |           tty_ldisc_ref_wait() {
0)           |             tty_ldisc_try() {
0)      0.615 us |           _spin_lock_irqsave();
0)      0.615 us |           _spin_unlock_irqrestore();
0)      5.436 us |         }
0)      6.427 us |       }
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 83a8df61
......@@ -14,20 +14,25 @@
#include "trace.h"
#define TRACE_GRAPH_INDENT 2
/* Spaces between function call and time duration */
#define TRACE_GRAPH_TIMESPACE_ENTRY " "
/* Spaces between function call and closing braces */
#define TRACE_GRAPH_TIMESPACE_RET " "
/* Flag options */
#define TRACE_GRAPH_PRINT_OVERRUN 0x1
#define TRACE_GRAPH_PRINT_CPU 0x2
#define TRACE_GRAPH_PRINT_OVERHEAD 0x4
static struct tracer_opt trace_opts[] = {
/* Display overruns or not */
{ TRACER_OPT(overrun, TRACE_GRAPH_PRINT_OVERRUN) },
/* Display overruns ? */
{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
/* Display CPU ? */
{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
/* Display Overhead ? */
{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
{ } /* Empty entry */
};
static struct tracer_flags tracer_flags = {
.val = 0, /* Don't display overruns by default */
/* Don't display overruns by default */
.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD,
.opts = trace_opts
};
......@@ -56,6 +61,36 @@ static void graph_trace_reset(struct trace_array *tr)
unregister_ftrace_graph();
}
static inline int log10_cpu(int nb)
{
if (nb / 100)
return 3;
if (nb / 10)
return 2;
return 1;
}
static enum print_line_t
print_graph_cpu(struct trace_seq *s, int cpu)
{
int i;
int ret;
int log10_this = log10_cpu(cpu);
int log10_all = log10_cpu(cpus_weight_nr(cpu_online_map));
for (i = 0; i < log10_all - log10_this; i++) {
ret = trace_seq_printf(s, " ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_printf(s, "%d) ", cpu);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
return TRACE_TYPE_HANDLED;
}
/* If the pid changed since the last trace, output this event */
static int verif_pid(struct trace_seq *s, pid_t pid, int cpu)
{
......@@ -67,8 +102,7 @@ static int verif_pid(struct trace_seq *s, pid_t pid, int cpu)
last_pid[cpu] = pid;
comm = trace_find_cmdline(pid);
return trace_seq_printf(s, "\nCPU[%03d] "
" ------------8<---------- thread %s-%d"
return trace_seq_printf(s, "\n------------8<---------- thread %s-%d"
" ------------8<----------\n\n",
cpu, comm, pid);
}
......@@ -86,7 +120,7 @@ trace_branch_is_leaf(struct trace_iterator *iter,
if (!ring_iter)
return false;
event = ring_buffer_iter_peek(iter->buffer_iter[iter->cpu], NULL);
event = ring_buffer_iter_peek(ring_iter, NULL);
if (!event)
return false;
......@@ -108,7 +142,7 @@ static inline int
print_graph_duration(unsigned long long duration, struct trace_seq *s)
{
unsigned long nsecs_rem = do_div(duration, 1000);
return trace_seq_printf(s, "+ %llu.%lu us\n", duration, nsecs_rem);
return trace_seq_printf(s, "%4llu.%3lu us | ", duration, nsecs_rem);
}
/* Signal a overhead of time execution to the output */
......@@ -136,8 +170,8 @@ print_graph_entry_leaf(struct trace_iterator *iter,
struct ring_buffer_event *event;
struct ftrace_graph_ent *call;
unsigned long long duration;
int i;
int ret;
int i;
event = ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
ret_entry = ring_buffer_event_data(event);
......@@ -145,8 +179,19 @@ print_graph_entry_leaf(struct trace_iterator *iter,
call = &entry->graph_ent;
duration = graph_ret->rettime - graph_ret->calltime;
/* Must not exceed 8 characters: 9999.999 us */
if (duration > 10000000ULL)
duration = 9999999ULL;
/* Overhead */
ret = print_graph_overhead(duration, s);
if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
ret = print_graph_overhead(duration, s);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* Duration */
ret = print_graph_duration(duration, s);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
......@@ -161,16 +206,7 @@ print_graph_entry_leaf(struct trace_iterator *iter,
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = trace_seq_printf(s, "();");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
/* Duration */
ret = trace_seq_printf(s, TRACE_GRAPH_TIMESPACE_ENTRY);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = print_graph_duration(duration, s);
ret = trace_seq_printf(s, "();\n");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
......@@ -186,9 +222,14 @@ print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
struct ftrace_graph_ent *call = &entry->graph_ent;
/* No overhead */
ret = trace_seq_printf(s, " ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
ret = trace_seq_printf(s, " ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* No time */
ret = trace_seq_printf(s, " | ");
/* Function */
for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
......@@ -201,12 +242,7 @@ print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = trace_seq_printf(s, "() {");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
/* No duration to print at this state */
ret = trace_seq_printf(s, TRACE_GRAPH_TIMESPACE_ENTRY "-\n");
ret = trace_seq_printf(s, "() {\n");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
......@@ -220,12 +256,16 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
int ret;
struct trace_entry *ent = iter->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;
/* Cpu */
if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
ret = print_graph_cpu(s, cpu);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
if (trace_branch_is_leaf(iter, field))
return print_graph_entry_leaf(iter, field, s);
......@@ -242,17 +282,30 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
int ret;
unsigned long long duration = trace->rettime - trace->calltime;
/* Must not exceed 8 characters: xxxx.yyy us */
if (duration > 10000000ULL)
duration = 9999999ULL;
/* Pid */
if (!verif_pid(s, ent->pid, cpu))
return TRACE_TYPE_PARTIAL_LINE;
/* Cpu */
ret = trace_seq_printf(s, "CPU[%03d] ", cpu);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
ret = print_graph_cpu(s, cpu);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* Overhead */
ret = print_graph_overhead(duration, s);
if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
ret = print_graph_overhead(duration, s);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* Duration */
ret = print_graph_duration(duration, s);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
......@@ -263,16 +316,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_printf(s, "} ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
/* Duration */
ret = trace_seq_printf(s, TRACE_GRAPH_TIMESPACE_RET);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = print_graph_duration(duration, s);
ret = trace_seq_printf(s, "}\n");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
......
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