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Message-ID: <20100324071638.GA1979@jolsa.lab.eng.brq.redhat.com>
Date: Wed, 24 Mar 2010 08:16:38 +0100
From: Jiri Olsa <jolsa@...hat.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 2/4] tracing: graph output support for irqsoff tracer
On Tue, Mar 23, 2010 at 09:19:16PM -0400, Steven Rostedt wrote:
> On Wed, 2010-03-10 at 08:51 +0100, Jiri Olsa wrote:
>
> > @@ -993,14 +991,6 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
> > if (ret != TRACE_TYPE_HANDLED)
> > return ret;
> > break;
> > - default:
> > - event = ftrace_find_event(ent->type);
> > - if (!event)
> > - return TRACE_TYPE_UNHANDLED;
> > -
> > - ret = event->trace(iter, sym_flags);
> > - if (ret != TRACE_TYPE_HANDLED)
> > - return ret;
> > }
> >
>
> This has the same effect as the problem with the first patch:
>
> was:
>
> 2) | _raw_spin_unlock_irqrestore() {
> 2) | /* lock_release: ffffffff816969a8 random_read_wait.lock */
> 2) 6.022 us | }
> 2) + 27.632 us | }
> 2) 2.939 us | kill_fasync();
> 2) | _raw_spin_unlock_irqrestore() {
> 2) | /* lock_release: ffffffff816967f0 &input_pool.lock */
> 2) 5.471 us | }
> 2) + 56.740 us | }
> 2) + 88.357 us | }
> 2) + 94.026 us | }
>
>
> is now:
>
> 2) | _raw_spin_unlock_irqrestore() {
> <idle>-0 [002] 411.798721: lock_release: ffffffff816969a8 random_read_wait.lock
> 2) 6.022 us | }
> 2) + 27.632 us | }
> 2) 2.939 us | kill_fasync();
> 2) | _raw_spin_unlock_irqrestore() {
> <idle>-0 [002] 411.798741: lock_release: ffffffff816967f0 &input_pool.lock
> 2) 5.471 us | }
> 2) + 56.740 us | }
> 2) + 88.357 us | }
> 2) + 94.026 us | }
>
>
> Please, before you apply any patch do the following:
>
> (assuming debugfs is at /debug)
>
> # echo 1 > /debug/tracing/events/enable
> # echo function_graph > /debug/tracing/current_tracer
> # cat /debug/tracing/trace
>
> Examine what you see.
>
> Then apply all your patches, and repeat the above. Make sure the
> formatting is the same.
hi,
shoot, looks like I forgot about comments... sending new version soon :)
thanks,
jirka
>
> Thanks,
>
> -- Steve
>
>
> > /* Strip ending newline */
> > @@ -1066,8 +1056,11 @@ print_graph_function(struct trace_iterator *iter)
> > trace_assign_type(field, entry);
> > return print_graph_return(&field->ret, s, entry, iter);
> > }
> > - default:
> > + case TRACE_BPRINT:
> > + case TRACE_PRINT:
> > return print_graph_comment(s, entry, iter);
> > + default:
> > + return TRACE_TYPE_UNHANDLED;
> > }
> >
> > return TRACE_TYPE_HANDLED;
> > @@ -1101,7 +1094,7 @@ static void print_lat_header(struct seq_file *s)
> > seq_printf(s, "#%.*s|||| / \n", size, spaces);
> > }
> >
> > -static void print_graph_headers(struct seq_file *s)
> > +void print_graph_headers(struct seq_file *s)
> > {
> > int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
> >
> > @@ -1137,7 +1130,7 @@ static void print_graph_headers(struct seq_file *s)
> > seq_printf(s, " | | | |\n");
> > }
> >
> > -static void graph_trace_open(struct trace_iterator *iter)
> > +void graph_trace_open(struct trace_iterator *iter)
> > {
> > /* pid and depth on the last trace processed */
> > struct fgraph_data *data;
> > @@ -1172,7 +1165,7 @@ static void graph_trace_open(struct trace_iterator *iter)
> > pr_warning("function graph tracer: not enough memory\n");
> > }
> >
> > -static void graph_trace_close(struct trace_iterator *iter)
> > +void graph_trace_close(struct trace_iterator *iter)
> > {
> > struct fgraph_data *data = iter->private;
> >
> > diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
> > index 2974bc7..d0c6d6c 100644
> > --- a/kernel/trace/trace_irqsoff.c
> > +++ b/kernel/trace/trace_irqsoff.c
> > @@ -34,6 +34,9 @@ static int trace_type __read_mostly;
> >
> > static int save_lat_flag;
> >
> > +static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
> > +static int start_irqsoff_tracer(struct trace_array *tr, int graph);
> > +
> > #ifdef CONFIG_PREEMPT_TRACER
> > static inline int
> > preempt_trace(void)
> > @@ -55,6 +58,23 @@ irq_trace(void)
> > # define irq_trace() (0)
> > #endif
> >
> > +#define TRACE_DISPLAY_GRAPH 1
> > +
> > +static struct tracer_opt trace_opts[] = {
> > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > + /* display latency trace as call graph */
> > + { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
> > +#endif
> > + { } /* Empty entry */
> > +};
> > +
> > +static struct tracer_flags tracer_flags = {
> > + .val = 0,
> > + .opts = trace_opts,
> > +};
> > +
> > +#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
> > +
> > /*
> > * Sequence count - we record it when starting a measurement and
> > * skip the latency if the sequence has changed - some other section
> > @@ -108,6 +128,109 @@ static struct ftrace_ops trace_ops __read_mostly =
> > };
> > #endif /* CONFIG_FUNCTION_TRACER */
> >
> > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > +static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
> > +{
> > + int cpu;
> > +
> > + if (!(bit & TRACE_DISPLAY_GRAPH))
> > + return -EINVAL;
> > +
> > + if (!(is_graph() ^ set))
> > + return 0;
> > +
> > + stop_irqsoff_tracer(irqsoff_trace, !set);
> > +
> > + for_each_possible_cpu(cpu)
> > + per_cpu(tracing_cpu, cpu) = 0;
> > +
> > + tracing_max_latency = 0;
> > + tracing_reset_online_cpus(irqsoff_trace);
> > +
> > + return start_irqsoff_tracer(irqsoff_trace, set);
> > +}
> > +
> > +static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
> > +{
> > + struct trace_array *tr = irqsoff_trace;
> > + struct trace_array_cpu *data;
> > + unsigned long flags;
> > + long disabled;
> > + int ret;
> > + int cpu;
> > + int pc;
> > +
> > + cpu = raw_smp_processor_id();
> > + if (likely(!per_cpu(tracing_cpu, cpu)))
> > + return 0;
> > +
> > + local_save_flags(flags);
> > + /* slight chance to get a false positive on tracing_cpu */
> > + if (!irqs_disabled_flags(flags))
> > + return 0;
> > +
> > + data = tr->data[cpu];
> > + disabled = atomic_inc_return(&data->disabled);
> > +
> > + if (likely(disabled == 1)) {
> > + pc = preempt_count();
> > + ret = __trace_graph_entry(tr, trace, flags, pc);
> > + } else
> > + ret = 0;
> > +
> > + atomic_dec(&data->disabled);
> > + return ret;
> > +}
> > +
> > +static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
> > +{
> > + struct trace_array *tr = irqsoff_trace;
> > + struct trace_array_cpu *data;
> > + unsigned long flags;
> > + long disabled;
> > + int cpu;
> > + int pc;
> > +
> > + cpu = raw_smp_processor_id();
> > + if (likely(!per_cpu(tracing_cpu, cpu)))
> > + return;
> > +
> > + local_save_flags(flags);
> > + /* slight chance to get a false positive on tracing_cpu */
> > + if (!irqs_disabled_flags(flags))
> > + return;
> > +
> > + data = tr->data[cpu];
> > + disabled = atomic_inc_return(&data->disabled);
> > +
> > + if (likely(disabled == 1)) {
> > + pc = preempt_count();
> > + __trace_graph_return(tr, trace, flags, pc);
> > + }
> > +
> > + atomic_dec(&data->disabled);
> > +}
> > +
> > +static void irqsoff_trace_open(struct trace_iterator *iter)
> > +{
> > + if (is_graph())
> > + graph_trace_open(iter);
> > +
> > +}
> > +
> > +static void irqsoff_trace_close(struct trace_iterator *iter)
> > +{
> > + if (iter->private)
> > + graph_trace_close(iter);
> > +}
> > +
> > +#else
> > +static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
> > +{
> > + return -EINVAL;
> > +}
> > +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
> > +
> > /*
> > * Should this new latency be reported/recorded?
> > */
> > @@ -347,19 +470,36 @@ void trace_preempt_off(unsigned long a0, unsigned long a1)
> > }
> > #endif /* CONFIG_PREEMPT_TRACER */
> >
> > -static void start_irqsoff_tracer(struct trace_array *tr)
> > +static int start_irqsoff_tracer(struct trace_array *tr, int graph)
> > {
> > - register_ftrace_function(&trace_ops);
> > - if (tracing_is_enabled())
> > + int ret = 0;
> > +
> > + if (!graph)
> > + ret = register_ftrace_function(&trace_ops);
> > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > + else
> > + ret = register_ftrace_graph(&irqsoff_graph_return,
> > + &irqsoff_graph_entry);
> > +#endif
> > +
> > + if (!ret && tracing_is_enabled())
> > tracer_enabled = 1;
> > else
> > tracer_enabled = 0;
> > +
> > + return ret;
> > }
> >
> > -static void stop_irqsoff_tracer(struct trace_array *tr)
> > +static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
> > {
> > tracer_enabled = 0;
> > - unregister_ftrace_function(&trace_ops);
> > +
> > + if (!graph)
> > + unregister_ftrace_function(&trace_ops);
> > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > + else
> > + unregister_ftrace_graph();
> > +#endif
> > }
> >
> > static void __irqsoff_tracer_init(struct trace_array *tr)
> > @@ -372,12 +512,14 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
> > /* make sure that the tracer is visible */
> > smp_wmb();
> > tracing_reset_online_cpus(tr);
> > - start_irqsoff_tracer(tr);
> > +
> > + if (start_irqsoff_tracer(tr, is_graph()))
> > + printk(KERN_ERR "failed to start irqsoff tracer\n");
> > }
> >
> > static void irqsoff_tracer_reset(struct trace_array *tr)
> > {
> > - stop_irqsoff_tracer(tr);
> > + stop_irqsoff_tracer(tr, is_graph());
> >
> > if (!save_lat_flag)
> > trace_flags &= ~TRACE_ITER_LATENCY_FMT;
> > @@ -409,9 +551,15 @@ static struct tracer irqsoff_tracer __read_mostly =
> > .start = irqsoff_tracer_start,
> > .stop = irqsoff_tracer_stop,
> > .print_max = 1,
> > + .flags = &tracer_flags,
> > + .set_flag = irqsoff_set_flag,
> > #ifdef CONFIG_FTRACE_SELFTEST
> > .selftest = trace_selftest_startup_irqsoff,
> > #endif
> > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > + .open = irqsoff_trace_open,
> > + .close = irqsoff_trace_close,
> > +#endif
> > };
> > # define register_irqsoff(trace) register_tracer(&trace)
> > #else
>
>
--
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