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Message-ID: <1348684250.22822.59.camel@gandalf.local.home>
Date: Wed, 26 Sep 2012 14:30:50 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: David Sharp <dhsharp@...gle.com>
Cc: linux-kernel@...r.kernel.org,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Subject: Re: [PATCH v4 3/3] tracing: format non-nanosec times from tsc clock
without a decimal point.
On Tue, 2012-09-25 at 15:29 -0700, David Sharp wrote:
> static int
> -lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
> - unsigned long rel_usecs)
> +lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
> {
> - return trace_seq_printf(s, " %4lldus%c: ", abs_usecs,
> - rel_usecs > preempt_mark_thresh ? '!' :
> - rel_usecs > 1 ? '+' : ' ');
> + unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
> + unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
> + unsigned long long abs_ts = iter->ts - iter->tr->time_start;
> + unsigned long long rel_ts = next_ts - iter->ts;
> + struct trace_seq *s = &iter->seq;
> + unsigned long mark_thresh;
> + int ret;
> +
> + if (in_ns) {
> + abs_ts = ns2usecs(abs_ts);
> + rel_ts = ns2usecs(rel_ts);
> + mark_thresh = preempt_mark_thresh_us;
> + } else
> + mark_thresh = preempt_mark_thresh_cycles;
> +
> + if (verbose && in_ns) {
> + unsigned long abs_msec = abs_ts;
> + unsigned long abs_usec = do_div(abs_msec, USEC_PER_MSEC);
> + unsigned long rel_msec = rel_ts;
> + unsigned long rel_usec = do_div(rel_msec, USEC_PER_MSEC);
> +
> + ret = trace_seq_printf(
> + s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
> + ns2usecs(iter->ts),
> + abs_msec, abs_usec,
> + rel_msec, rel_usec);
> + } else if (verbose && !in_ns) {
> + ret = trace_seq_printf(
> + s, "[%016llx] %lld (+%lld): ",
> + iter->ts, abs_ts, rel_ts);
> + } else { /* !verbose */
> + ret = trace_seq_printf(
> + s, " %4lld%s%c: ",
> + abs_ts,
> + in_ns ? "us" : "",
> + rel_ts > mark_thresh ? '!' :
> + rel_ts > 1 ? '+' : ' ');
I still think the annotations are meaningless for counters. Even if the
counter is a timer like the tsc, as it does not coincide with real time
(us), I say just don't print it for counters.
This is not helpful:
<idle>-0 0d..1 168+: trace_hardirqs_off_thunk <-apic_timer_interrupt
<idle>-0 0d..1 672+: smp_apic_timer_interrupt <-apic_timer_interrupt
<idle>-0 0d..1 1224+: irq_enter <-smp_apic_timer_interrupt
<idle>-0 0d..1 1720+: rcu_irq_enter <-irq_enter
<idle>-0 0d..1 2328+: rcu_idle_exit_common.isra.38 <-rcu_irq_enter
<idle>-0 0d..1 3016+: local_bh_disable <-irq_enter
<idle>-0 0d..1 3512+: __local_bh_disable <-irq_enter
<idle>-0 0d.s1 4120+: tick_check_idle <-irq_enter
<idle>-0 0d.s1 4632+: tick_check_oneshot_broadcast <-tick_check_idle
<idle>-0 0d.s1 5296+: ktime_get <-tick_check_idle
<idle>-0 0d.s1 6104+: tick_nohz_stop_idle <-tick_check_idle
<idle>-0 0d.s1 6616+: update_ts_time_stats <-tick_nohz_stop_idle
<idle>-0 0d.s1 7144+: nr_iowait_cpu <-update_ts_time_stats
<idle>-0 0d.s1 7720+: ktime_get <-sched_clock_tick
<idle>-0 0d.s1 8480+: touch_softlockup_watchdog <-tick_check_idle
<idle>-0 0d.s1 9120+: tick_do_update_jiffies64 <-tick_check_idle
<idle>-0 0d.s1 9648+: _raw_spin_lock <-tick_do_update_jiffies64
> + }
> + return ret;
> }
>
> int trace_print_context(struct trace_iterator *iter)
> {
> struct trace_seq *s = &iter->seq;
> struct trace_entry *entry = iter->ent;
> - unsigned long long t = ns2usecs(iter->ts);
> - unsigned long usec_rem = do_div(t, USEC_PER_SEC);
> - unsigned long secs = (unsigned long)t;
> + unsigned long long t;
> + unsigned long secs, usec_rem;
> char comm[TASK_COMM_LEN];
> int ret;
>
> @@ -644,8 +680,13 @@ int trace_print_context(struct trace_iterator *iter)
> return 0;
> }
>
> - return trace_seq_printf(s, " %5lu.%06lu: ",
> - secs, usec_rem);
> + if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
> + t = ns2usecs(iter->ts);
> + usec_rem = do_div(t, USEC_PER_SEC);
> + secs = (unsigned long)t;
> + return trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
You took away the space before %5.
> + } else
> + return trace_seq_printf(s, "%12llu: ", iter->ts);
here too.
We end up with this:
<idle>-0 [002] d.h11968173392984: _raw_spin_lock_irqsave <-try_to_wake_up
<idle>-0 [002] d.h11968173393704: add_preempt_count <-_raw_spin_lock_irqsave
<idle>-0 [002] d.h21968173394568: task_waking_fair <-try_to_wake_up
<idle>-0 [002] d.h21968173395488: select_task_rq_fair <-select_task_rq
<idle>-0 [002] d.h21968173396240: __rcu_read_lock <-select_task_rq_fair
<idle>-0 [002] d.h21968173397136: idle_cpu <-select_task_rq_fair
<idle>-0 [002] d.h21968173397816: __rcu_read_unlock <-select_task_rq_fair
<idle>-0 [002] d.h21968173398608: cpus_share_cache <-try_to_wake_up
<idle>-0 [002] d.h21968173399272: _raw_spin_lock <-try_to_wake_up
<idle>-0 [002] d.h21968173399888: add_preempt_count <-_raw_spin_lock
<idle>-0 [002] d.h31968173400608: ttwu_do_activate.constprop.87 <-try_to_wake_up
<idle>-0 [002] d.h31968173401272: activate_task <-ttwu_do_activate.constprop.87
<idle>-0 [002] d.h31968173401912: enqueue_task <-ttwu_do_activate.constprop.87
-- Steve
> }
>
> int trace_print_lat_context(struct trace_iterator *iter)
> @@ -659,36 +700,29 @@ int trace_print_lat_context(struct trace_iterator *iter)
> *next_entry = trace_find_next_entry(iter, NULL,
> &next_ts);
> unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
> - unsigned long abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
> - unsigned long rel_usecs;
>
> /* Restore the original ent_size */
> iter->ent_size = ent_size;
>
> if (!next_entry)
> next_ts = iter->ts;
> - rel_usecs = ns2usecs(next_ts - iter->ts);
--
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