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
>
> 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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