Messages in this thread | | | Subject | Re: [PATCH v3 2/3] tracing: Add trace_irqsoff tracepoints | From | Daniel Wagner <> | Date | Mon, 29 Aug 2016 11:43:50 +0200 |
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Hi Binoy,
Some minor nitpicking.
On 08/29/2016 08:55 AM, Binoy Jayan wrote: > +DECLARE_EVENT_CLASS(latency_template, > + TP_PROTO(int ltype, int cpu, cycles_t latency), > + > + TP_ARGS(ltype, cpu, latency), > + > + TP_STRUCT__entry( > + __field(int, ltype) > + __field(int, cpu) > + __field(cycles_t, latency) > + ), > + > + TP_fast_assign( > + __entry->ltype = ltype; > + __entry->cpu = cpu; > + __entry->latency = latency; > + ), > + > + TP_printk("ltype=%d, cpu=%d, latency=%lu", > + __entry->ltype, __entry->cpu, (unsigned long) __entry->latency) > +);
As Steven already pointed out, the cpu field is available in all traces. It's one of the predefined fields (see kernel/trace/trace_events.c/trace_define_generic_fields()). Just drop it.
> + > +DEFINE_EVENT(latency_template, latency_preempt, > + TP_PROTO(int ltype, int cpu, cycles_t latency), > + TP_ARGS(ltype, cpu, latency)); > + > +#endif /* _TRACE_HIST_H */ > + > +/* This part must be outside protection */ > +#include <trace/define_trace.h> > diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c > index 03cdff8..d4f2b25 100644 > --- a/kernel/trace/trace_irqsoff.c > +++ b/kernel/trace/trace_irqsoff.c > @@ -13,14 +13,27 @@ > #include <linux/uaccess.h> > #include <linux/module.h> > #include <linux/ftrace.h> > +#include <linux/percpu-defs.h> > + > +#include <trace/events/sched.h> > > #include "trace.h" > > +#define CREATE_TRACE_POINTS > +#include <trace/events/latency.h> > + > static struct trace_array *irqsoff_trace __read_mostly; > static int tracer_enabled __read_mostly; > > -static DEFINE_PER_CPU(int, tracing_cpu); > +enum latency_type { > + TS_IRQ, > + TS_PREEMPT, > + TS_CRITTIME, > + TS_MAX > +};
Come to think of it, the TS_ prefix doesn't really make sense, maybe LT_ would be more consistent (short hand for latency type).
> +static DEFINE_PER_CPU(int, tracing_cpu); > +static DEFINE_PER_CPU(cycle_t, lat_ts[TS_MAX]); > static DEFINE_RAW_SPINLOCK(max_trace_lock); > > enum { > @@ -419,9 +432,19 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) > atomic_dec(&data->disabled); > } > > +static inline void latency_trace(enum latency_type type) > +{ > + trace_latency_preempt(type, raw_smp_processor_id(), > + (cycle_t) trace_clock_local() - this_cpu_read(lat_ts[type])); > + > +}
empty line here
> /* start and stop critical timings used to for stoppage (in idle) */ > void start_critical_timings(void) > { > + if (trace_latency_preempt_enabled()) > + this_cpu_write(lat_ts[TS_CRITTIME], > + (cycle_t) trace_clock_local()); > +
Introduce a inline function like the latency_trace() function. No need to open code this logic 3 times.
> if (preempt_trace() || irq_trace()) > start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); > } > @@ -431,6 +454,10 @@ void stop_critical_timings(void) > { > if (preempt_trace() || irq_trace()) > stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); > + > + if (trace_latency_preempt_enabled()) > + latency_trace(TS_CRITTIME); > + > } > EXPORT_SYMBOL_GPL(stop_critical_timings); > > @@ -438,6 +465,9 @@ EXPORT_SYMBOL_GPL(stop_critical_timings); > #ifdef CONFIG_PROVE_LOCKING > void time_hardirqs_on(unsigned long a0, unsigned long a1) > { > + if (trace_latency_preempt_enabled()) { > + latency_trace(TS_IRQ); > + }
Please follow the style of the rest of the file. Just drop the brackets.
> if (!preempt_trace() && irq_trace()) > stop_critical_timing(a0, a1); > } > @@ -446,6 +476,11 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1) > { > if (!preempt_trace() && irq_trace()) > start_critical_timing(a0, a1); > + > + if (trace_latency_preempt_enabled()) { > + this_cpu_write(lat_ts[TS_IRQ], > + (cycle_t) trace_clock_local()); > + }
Same thing.
> } > > #else /* !CONFIG_PROVE_LOCKING */ > @@ -503,6 +538,9 @@ EXPORT_SYMBOL(trace_hardirqs_off_caller); > #ifdef CONFIG_PREEMPT_TRACER > void trace_preempt_on(unsigned long a0, unsigned long a1) > { > + if (trace_latency_preempt_enabled()) > + latency_trace(TS_PREEMPT); > + > if (preempt_trace() && !irq_trace()) > stop_critical_timing(a0, a1); > } > @@ -511,6 +549,11 @@ void trace_preempt_off(unsigned long a0, unsigned long a1) > { > if (preempt_trace() && !irq_trace()) > start_critical_timing(a0, a1); > + > + if (trace_latency_preempt_enabled()) { > + this_cpu_write(lat_ts[TS_PREEMPT], > + (cycle_t) trace_clock_local()); > + }
And here too.
> } > #endif /* CONFIG_PREEMPT_TRACER */
cheers, daniel
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