trace: better manage the context info for events
Impact: make trace_event more convenient for tracers
All tracers (for the moment) that use the struct trace_event want to
have the context info printed before their own output: the pid/cmdline,
cpu, and timestamp.
But some other tracers that want to implement their trace_event
callbacks will not necessary need these information or they may want to
format them as they want.
This patch adds a new default-enabled trace option:
TRACE_ITER_CONTEXT_INFO When disabled through:
echo nocontext-info > /debugfs/tracing/trace_options
The pid, cpu and timestamps headers will not be printed.
IE with the sched_switch tracer with context-info (default):
bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle>
<idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0
<idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0
events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle>
Without context-info:
2935:120:S ==> [001] 0:140:R <idle>
0:140:R + [000] 11:115:S events/0
0:140:R ==> [000] 11:115:R events/0
11:115:S ==> [000] 0:140:R <idle>
A tracer can disable it at runtime by clearing the bit
TRACE_ITER_CONTEXT_INFO in trace_flags.
The print routines were renamed to trace_print_context and
trace_print_lat_context, so that they can be used by tracers if they
want to use them for one of the trace_event callbacks.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2f8ac1f..5ec49c3 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -227,7 +227,7 @@
/* trace_flags holds trace_options default values */
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
- TRACE_ITER_ANNOTATE;
+ TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
/**
* trace_wake_up - wake up tasks waiting for trace input
@@ -285,6 +285,7 @@
"userstacktrace",
"sym-userobj",
"printk-msg-only",
+ "context-info",
NULL
};
@@ -1171,8 +1172,8 @@
}
/* Find the next real entry, without updating the iterator itself */
-static struct trace_entry *
-find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
+struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
+ int *ent_cpu, u64 *ent_ts)
{
return __find_next_entry(iter, ent_cpu, ent_ts);
}
@@ -1351,57 +1352,6 @@
seq_puts(m, "\n");
}
-static void
-lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
-{
- int hardirq, softirq;
- char *comm;
-
- comm = trace_find_cmdline(entry->pid);
-
- trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
- trace_seq_printf(s, "%3d", cpu);
- trace_seq_printf(s, "%c%c",
- (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
- (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
- ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
-
- hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
- softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
- if (hardirq && softirq) {
- trace_seq_putc(s, 'H');
- } else {
- if (hardirq) {
- trace_seq_putc(s, 'h');
- } else {
- if (softirq)
- trace_seq_putc(s, 's');
- else
- trace_seq_putc(s, '.');
- }
- }
-
- if (entry->preempt_count)
- trace_seq_printf(s, "%x", entry->preempt_count);
- else
- trace_seq_puts(s, ".");
-}
-
-unsigned long preempt_mark_thresh = 100;
-
-static void
-lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
- unsigned long rel_usecs)
-{
- trace_seq_printf(s, " %4lldus", abs_usecs);
- if (rel_usecs > preempt_mark_thresh)
- trace_seq_puts(s, "!: ");
- else if (rel_usecs > 1)
- trace_seq_puts(s, "+: ");
- else
- trace_seq_puts(s, " : ");
-}
-
static void test_cpu_buff_start(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
@@ -1419,46 +1369,24 @@
trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
}
-static enum print_line_t
-print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
+static enum print_line_t print_lat_fmt(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
- struct trace_entry *next_entry;
struct trace_event *event;
- unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
struct trace_entry *entry = iter->ent;
- unsigned long abs_usecs;
- unsigned long rel_usecs;
- u64 next_ts;
- char *comm;
int ret;
test_cpu_buff_start(iter);
- next_entry = find_next_entry(iter, NULL, &next_ts);
- if (!next_entry)
- next_ts = iter->ts;
- rel_usecs = ns2usecs(next_ts - iter->ts);
- abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
+ event = ftrace_find_event(entry->type);
- if (verbose) {
- comm = trace_find_cmdline(entry->pid);
- trace_seq_printf(s, "%16s %5d %3d %d %08x %08x [%08lx]"
- " %ld.%03ldms (+%ld.%03ldms): ",
- comm,
- entry->pid, cpu, entry->flags,
- entry->preempt_count, trace_idx,
- ns2usecs(iter->ts),
- abs_usecs/1000,
- abs_usecs % 1000, rel_usecs/1000,
- rel_usecs % 1000);
- } else {
- lat_print_generic(s, entry, cpu);
- lat_print_timestamp(s, abs_usecs, rel_usecs);
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ ret = trace_print_lat_context(iter);
+ if (ret)
+ return ret;
}
- event = ftrace_find_event(entry->type);
if (event && event->latency_trace) {
ret = event->latency_trace(s, entry, sym_flags);
if (ret)
@@ -1476,33 +1404,20 @@
unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
struct trace_entry *entry;
struct trace_event *event;
- unsigned long usec_rem;
- unsigned long long t;
- unsigned long secs;
- char *comm;
int ret;
entry = iter->ent;
test_cpu_buff_start(iter);
- comm = trace_find_cmdline(iter->ent->pid);
-
- t = ns2usecs(iter->ts);
- usec_rem = do_div(t, 1000000ULL);
- secs = (unsigned long)t;
-
- ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
-
event = ftrace_find_event(entry->type);
+
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ ret = trace_print_context(iter);
+ if (ret)
+ return ret;
+ }
+
if (event && event->trace) {
ret = event->trace(s, entry, sym_flags);
if (ret)
@@ -1525,10 +1440,12 @@
entry = iter->ent;
- ret = trace_seq_printf(s, "%d %d %llu ",
- entry->pid, iter->cpu, iter->ts);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ ret = trace_seq_printf(s, "%d %d %llu ",
+ entry->pid, iter->cpu, iter->ts);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ }
event = ftrace_find_event(entry->type);
if (event && event->raw) {
@@ -1553,9 +1470,11 @@
entry = iter->ent;
- SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
- SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
- SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
+ SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
+ SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+ }
event = ftrace_find_event(entry->type);
if (event && event->hex)
@@ -1575,7 +1494,7 @@
trace_assign_type(field, entry);
- ret = trace_seq_printf(s, field->buf);
+ ret = trace_seq_printf(s, "%s", field->buf);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
@@ -1590,9 +1509,11 @@
entry = iter->ent;
- SEQ_PUT_FIELD_RET(s, entry->pid);
- SEQ_PUT_FIELD_RET(s, entry->cpu);
- SEQ_PUT_FIELD_RET(s, iter->ts);
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ SEQ_PUT_FIELD_RET(s, entry->pid);
+ SEQ_PUT_FIELD_RET(s, entry->cpu);
+ SEQ_PUT_FIELD_RET(s, iter->ts);
+ }
event = ftrace_find_event(entry->type);
if (event && event->binary)
@@ -1643,7 +1564,7 @@
return print_raw_fmt(iter);
if (iter->iter_flags & TRACE_FILE_LAT_FMT)
- return print_lat_fmt(iter, iter->idx, iter->cpu);
+ return print_lat_fmt(iter);
return print_trace_fmt(iter);
}