On Wed, Nov 19, 2014 at 01:35:15PM -0500, Steven Rostedt wrote:
> On Tue, 18 Nov 2014 14:57:26 +0900
> byungchul.p...@lge.com wrote:
>
> > From: Byungchul Park <byungchul.p...@lge.com>
> >
> > Currently, some tracers tracing latency print "!" or "+" just after time
> > to signal overhead, depending on the interval between events. Even it is
> > usually enough to do that, we sometimes need to be signaled for bigger
> > interval than 100 micro seconds.
> >
> > Signed-off-by: Byungchul Park <byungchul.p...@lge.com>
> > ---
> > Documentation/trace/ftrace.txt | 8 +++++---
> > kernel/trace/trace_output.c | 23 ++++++++++++++++++-----
> > 2 files changed, 23 insertions(+), 8 deletions(-)
> >
> > diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
> > index f827e2f..64efb3e 100644
> > --- a/Documentation/trace/ftrace.txt
> > +++ b/Documentation/trace/ftrace.txt
> > @@ -680,9 +680,11 @@ The above is mostly meaningful for kernel developers.
> > needs to be fixed to be only relative to the same CPU.
> > The marks are determined by the difference between this
> > current trace and the next trace.
> > - '!' - greater than preempt_mark_thresh (default 100)
> > - '+' - greater than 1 microsecond
> > - ' ' - less than or equal to 1 microsecond.
> > + '$' - greater than 1 second
> > + '#' - greater than 1000 microsecond
> > + '!' - greater than 100 microsecond
> > + '+' - greater than 10 microsecond
> > + ' ' - less than or equal to 10 microsecond.
> >
> > The rest is the same as the 'trace' file.
> >
> > diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> > index c6977d5..3fd3017 100644
> > --- a/kernel/trace/trace_output.c
> > +++ b/kernel/trace/trace_output.c
> > @@ -124,7 +124,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned
> > long val,
> >
> > if (ret == (const char *)(trace_seq_buffer_ptr(p)))
> > trace_seq_printf(p, "0x%lx", val);
> > -
> > +
> > trace_seq_putc(p, 0);
> >
> > return ret;
> > @@ -471,7 +471,21 @@ lat_print_generic(struct trace_seq *s, struct
> > trace_entry *entry, int cpu)
> > return trace_print_lat_fmt(s, entry);
> > }
> >
> > -static unsigned long preempt_mark_thresh_us = 100;
> > +#undef MARK
> > +#define MARK(v, s) {.val = v, .sym = s}
> > +static const struct trace_mark mark[] = {
> > + MARK(1000000000ULL , '$'), /* 1 sec */
> > + MARK(1000000ULL , '#'), /* 1000 usecs */
> > + MARK(100000ULL , '!'), /* 100 usecs */
> > + MARK(10000ULL , '+'), /* 10 usecs */
> > + MARK(0ULL , ' '), /* 0 usecs */
> > +};
> > +#undef MARK
> > +
> > +static inline char find_trace_mark(unsigned long long d)
> > +{
> > + return trace_duration_mark(d, mark, ARRAY_SIZE(mark));
> > +}
>
> This is the exact same code as in function_graph tracer. Nuke the one
> from function graph and make this one a non static function, and have
> function graph tracer use it. trace_output.c is always compiled with
> tracing.
>
> In fact, remove all the code from trace.h, and move it here. Just
> have this function be global and rename it to:
>
> trace_find_mark()
>
> -- Steve
OK. I will do that.
Thank you,
BYungchul
>
>
> >
> > static int
> > lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
> > @@ -506,8 +520,7 @@ 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 ? '+' : ' ');
> > + find_trace_mark(rel_ts * NSEC_PER_USEC));
> > } else { /* !verbose && !in_ns */
> > return trace_seq_printf(s, " %4lld: ", abs_ts);
> > }
> > @@ -692,7 +705,7 @@ int register_ftrace_event(struct trace_event *event)
> > goto out;
> >
> > } else {
> > -
> > +
> > event->type = next_event_type++;
> > list = &ftrace_event_list;
> > }
>
> --
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