Re: [PATCH v2 3/3] tracing: add additional marks to signal very large delay

From: Steven Rostedt
Date: Thu Nov 13 2014 - 22:38:12 EST


On Wed, 5 Nov 2014 16:18:46 +0900
byungchul.park@xxxxxxx wrote:

> -static unsigned long preempt_mark_thresh_us = 100;
> +DEFINE_MARK_STRUCT = {
> + DEFINE_MARK(0ULL , ' '), /* 0 usecs */
> + DEFINE_MARK(10000ULL , '+'), /* 10 usecs */
> + DEFINE_MARK(100000ULL , '!'), /* 100 usecs */
> + DEFINE_MARK(1000000ULL , '#'), /* 1000 usecs */
> + DEFINE_MARK(1000000000ULL , '$'), /* 1 sec */
> +};

OK, I see why you did the macro magic here. But it's still obfuscates
the code.

Instead of having that find_trace_mark() be a static function, just
make it defined in trace_output.c that function_graph calls. This code
is used for outputting to userspace and a function call is not going to
be noticed.

As it would now be a global function (although only defined in
kernel/trace), we need to make the name a bit more specific. Instead of
calling it find_trace_mark(), call it trace_duration_mark().

-- Steve

>
> static int
> lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
> @@ -506,8 +512,7 @@ lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
> return trace_seq_printf(
> s, " %4lldus%c: ",
> abs_ts,
> - rel_ts > preempt_mark_thresh_us ? '!' :
> - rel_ts > 1 ? '+' : ' ');
> + MARK(rel_ts * NSEC_PER_USEC));
> } else { /* !verbose && !in_ns */
> return trace_seq_printf(s, " %4lld: ", abs_ts);
> }
> @@ -692,7 +697,7 @@ int register_ftrace_event(struct trace_event *event)
> goto out;
>
> } else {
> -
> +
> event->type = next_event_type++;
> list = &ftrace_event_list;
> }

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