On Tue, 12 Feb 2019 23:23:57 +0100 Lukasz Luba <[email protected]> wrote:
> The patch adds a new file for with trace events for devfreq > framework. They are used for performance analysis of the framework. > It also contains updates in MAINTAINERS file adding new entry for > devfreq maintainers. > > Signed-off-by: Lukasz Luba <[email protected]> > --- > MAINTAINERS | 1 + > include/trace/events/devfreq.h | 39 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 40 insertions(+) > create mode 100644 include/trace/events/devfreq.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index 9919840..c042fda 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -4447,6 +4447,7 @@ S: Maintained > F: drivers/devfreq/ > F: include/linux/devfreq.h > F: Documentation/devicetree/bindings/devfreq/ > +F: include/trace/events/devfreq.h > > DEVICE FREQUENCY EVENT (DEVFREQ-EVENT) > M: Chanwoo Choi <[email protected]> > diff --git a/include/trace/events/devfreq.h b/include/trace/events/devfreq.h > new file mode 100644 > index 0000000..fec9304 > --- /dev/null > +++ b/include/trace/events/devfreq.h > @@ -0,0 +1,39 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#undef TRACE_SYSTEM > +#define TRACE_SYSTEM devfreq > + > +#if !defined(_TRACE_DEVFREQ_H) || defined(TRACE_HEADER_MULTI_READ) > +#define _TRACE_DEVFREQ_H > + > +#include <linux/devfreq.h> > +#include <linux/tracepoint.h> > + > +TRACE_EVENT(devfreq_monitor, > + TP_PROTO(const char *dev_name, unsigned long freq, > + unsigned int polling_ms, unsigned long busy_time, > + unsigned long total_time), > + > + TP_ARGS(dev_name, freq, polling_ms, busy_time, total_time), > + > + TP_STRUCT__entry( > + __string(dev_name, dev_name) > + __field(unsigned long, freq) > + __field(unsigned int, polling_ms) > + __field(unsigned int, load) > + ), > + > + TP_fast_assign( > + __assign_str(dev_name, dev_name); > + __entry->freq = freq; > + __entry->polling_ms = polling_ms; > + __entry->load = (100 * busy_time) / total_time; How critical is the code that this trace event is called in. If it is not that critical (it is a slow path), then this is fine, but if this is not a slow path (something triggered 100 HZ or less), then I would recommend moving the above calculation to TP_printk(). A divide is a slow operation, and is best to do that in the post processing. The current location does the divide at the time of the tracepoint is called. I would also have a check to make sure that total_time is not zero here, otherwise that could be bad. __entry->busy_time = busy_time; __entry->total_time = total_time; > + ), > + > + TP_printk("dev_name=%s freq=%lu polling_ms=%u load=%u", > + __get_str(dev_name), __entry->freq, __entry->polling_ms, __entry->total_time == 0 ? 100 : __entry->busy_time / __entry->total_time) -- Steve > + __entry->load) > +); > +#endif /* _TRACE_DEVFREQ_H */ > + > +/* This part must be outside protection */ > +#include <trace/define_trace.h>
