summaryrefslogtreecommitdiffstats
path: root/kernel/trace/trace.c
diff options
context:
space:
mode:
authorSteven Rostedt <rostedt@goodmis.org>2008-11-12 17:52:38 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-13 09:49:24 +0100
commit12ef7d448613ead2babd41c3ebfa1fe03c20edef (patch)
tree252b12211d2bbf96e4a90625f0c6116c9a4bd7de /kernel/trace/trace.c
parentee6bce52276c0717ed3e63296e5d9465d339e923 (diff)
downloadop-kernel-dev-12ef7d448613ead2babd41c3ebfa1fe03c20edef.zip
op-kernel-dev-12ef7d448613ead2babd41c3ebfa1fe03c20edef.tar.gz
ftrace: CPU buffer start annotation clean ups
Impact: better handling of CPU buffer start annotation Because of the confusion with the per CPU buffers wrapping where one CPU might be more active at the end of the trace than the other CPUs causing that one CPU to have a shorter history. Kernel developers were confused by the "missing" data of that one CPU at the beginning of the trace output. An annotation was added to the trace output to show that the buffer had started: # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | ##### CPU 3 buffer started #### <idle>-0 [003] 158.192959: smp_apic_timer_interrupt [...] <idle>-0 [003] 161.556520: default_idle ##### CPU 1 buffer started #### <idle>-0 [001] 161.592494: hrtimer_force_reprogram [etc] But this annotation gets a bit messy when tracers do not fill the buffers. This patch does a couple of things: One) it adds a flag to trace_options to disable these annotations Two) it does not annotate if the tracer did not overflow its buffer. This makes the output much cleaner. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r--kernel/trace/trace.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 240423a..4a90462 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -205,7 +205,8 @@ static DEFINE_MUTEX(trace_types_lock);
static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
/* trace_flags holds trace_options default values */
-unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK;
+unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
+ TRACE_ITER_ANNOTATE;
/**
* trace_wake_up - wake up tasks waiting for trace input
@@ -261,6 +262,7 @@ static const char *trace_options[] = {
#ifdef CONFIG_BRANCH_TRACER
"branch",
#endif
+ "annotate",
NULL
};
@@ -1113,6 +1115,7 @@ void tracing_stop_function_trace(void)
enum trace_file_type {
TRACE_FILE_LAT_FMT = 1,
+ TRACE_FILE_ANNOTATE = 2,
};
static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
@@ -1532,6 +1535,12 @@ static void test_cpu_buff_start(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
+ if (!(trace_flags & TRACE_ITER_ANNOTATE))
+ return;
+
+ if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
+ return;
+
if (cpu_isset(iter->cpu, iter->started))
return;
@@ -2132,6 +2141,11 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
iter->trace = current_trace;
iter->pos = -1;
+ /* Annotate start of buffers if we had overruns */
+ if (ring_buffer_overruns(iter->tr->buffer))
+ iter->iter_flags |= TRACE_FILE_ANNOTATE;
+
+
for_each_tracing_cpu(cpu) {
iter->buffer_iter[cpu] =
OpenPOWER on IntegriCloud