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tracing/function-graph-tracer: improve duration output 

Impact: better trace output of duration for long calls

The old duration output didn't exceeded 9999.999 us to fit the column
and the nanosecs were always 3 numbers. As Ingo suggested, it's better
to have the whole microseconds elapsed time and shift the nanosecs precision
if needed to fit the maximum 7 numbers. And usec need more number, the case
should be rare and important enough to break a bit the column alignment to
show it.

So, depending of the duration value, we now have these patterns:

    u.nnn us
   uu.nnn us
  uuu.nnn us
 uuuu.nnn us
 uuuuu.nn us
 uuuuuu.n us
 uuuuuuuu..... us

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
5bit-waveforms
Frederic Weisbecker 2008-12-03 02:32:12 +01:00 committed by Ingo Molnar
parent 11e84acc40
commit 166d3c7994
1 changed files with 43 additions and 12 deletions
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55
kernel/trace/trace_functions_graph.c
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@ -232,11 +232,50 @@ trace_branch_is_leaf(struct trace_iterator *iter,
}
static inline int
static enum print_line_t
print_graph_duration(unsigned long long duration, struct trace_seq *s)
{
unsigned long nsecs_rem = do_div(duration, 1000);
return trace_seq_printf(s, "%4llu.%3lu us | ", duration, nsecs_rem);
/* log10(ULONG_MAX) + '\0' */
char msecs_str[21];
char nsecs_str[5];
int ret, len;
int i;
sprintf(msecs_str, "%lu", (unsigned long) duration);
/* Print msecs */
ret = trace_seq_printf(s, msecs_str);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
len = strlen(msecs_str);
/* Print nsecs (we don't want to exceed 7 numbers) */
if (len < 7) {
snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
ret = trace_seq_printf(s, ".%s", nsecs_str);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
len += strlen(nsecs_str);
}
ret = trace_seq_printf(s, " us ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
/* Print remaining spaces to fit the row's width */
for (i = len; i < 7; i++) {
ret = trace_seq_printf(s, " ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_printf(s, "| ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
return TRACE_TYPE_HANDLED;
}
/* Signal a overhead of time execution to the output */
@ -273,10 +312,6 @@ 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 */
if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
ret = print_graph_overhead(duration, s);
@ -286,7 +321,7 @@ print_graph_entry_leaf(struct trace_iterator *iter,
/* Duration */
ret = print_graph_duration(duration, s);
if (!ret)
if (ret == TRACE_TYPE_PARTIAL_LINE)
return TRACE_TYPE_PARTIAL_LINE;
/* Function */
@ -387,10 +422,6 @@ 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) == TRACE_TYPE_PARTIAL_LINE)
return TRACE_TYPE_PARTIAL_LINE;
@ -422,7 +453,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
/* Duration */
ret = print_graph_duration(duration, s);
if (!ret)
if (ret == TRACE_TYPE_PARTIAL_LINE)
return TRACE_TYPE_PARTIAL_LINE;
/* Closing brace */