Messages in this thread | | | Date | Tue, 30 Aug 2016 10:08:38 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v4 2/3] tracing: Add trace_irqsoff tracepoints |
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On Tue, 30 Aug 2016 15:58:43 +0530 Binoy Jayan <binoy.jayan@linaro.org> wrote:
> This work is based on work by Daniel Wagner. A few tracepoints are added > at the end of the critical section. With the hist trigger in place, the > hist trigger plots may be generated, with per-cpu breakdown of events > captured. It is based on linux kernel's event infrastructure. > > The following filter(s) may be used > > 'hist:key=latency.log2:val=hitcount:sort=latency' > 'hist:key=ltype,latency:val=hitcount:sort=latency if cpu==1' > 'hist:key=ltype:val=latency:sort=ltype if ltype==0 && cpu==2' > > Where ltype is > 0: IRQSOFF latency > 1: PREEMPTOFF Latency > 2: Critical Timings > > This captures only the latencies introduced by disabled irqs and > preemption. Additional per process data has to be captured to calculate > the effective latencies introduced for individual processes. > > Initial work - latency.patch > > [1] https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit/?h=v3.14-rt-rebase&id=56d50cc34943bbba12b8c5942ee1ae3b29f73acb > > Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org> > --- > include/trace/events/latency.h | 35 +++++++++++++++++++++++++++++++++++ > kernel/trace/trace_irqsoff.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 77 insertions(+) > create mode 100644 include/trace/events/latency.h > > diff --git a/include/trace/events/latency.h b/include/trace/events/latency.h > new file mode 100644 > index 0000000..e89be12 > --- /dev/null > +++ b/include/trace/events/latency.h > @@ -0,0 +1,35 @@ > +#undef TRACE_SYSTEM > +#define TRACE_SYSTEM latency > + > +#if !defined(_TRACE_HIST_H) || defined(TRACE_HEADER_MULTI_READ) > +#define _TRACE_HIST_H > + > +#include <linux/tracepoint.h> > + > +DECLARE_EVENT_CLASS(latency_template, > + TP_PROTO(int ltype, cycles_t latency), > + > + TP_ARGS(ltype, latency), > + > + TP_STRUCT__entry( > + __field(int, ltype) > + __field(cycles_t, latency) > + ), > + > + TP_fast_assign( > + __entry->ltype = ltype; > + __entry->latency = latency; > + ), > + > + TP_printk("ltype=%d, latency=%lu", > + __entry->ltype, (unsigned long) __entry->latency)
The print of ltype should be text and not a number. Well, you could have both text and a number, but a number is useless for those looking at traces.
There's infrastructure to do this, see __print_symbolic() and TRACE_DEFINE_ENUM().
-- Steve
> +); > + > +DEFINE_EVENT(latency_template, latency_preempt, > + TP_PROTO(int ltype, cycles_t latency), > + TP_ARGS(ltype, latency)); > + > +#endif /* _TRACE_HIST_H */ > +
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