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>
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 23e19d2..c66578f 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -232,11 +232,50 @@
}
-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 @@
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 @@
/* 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 @@
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 @@
/* Duration */
ret = print_graph_duration(duration, s);
- if (!ret)
+ if (ret == TRACE_TYPE_PARTIAL_LINE)
return TRACE_TYPE_PARTIAL_LINE;
/* Closing brace */