1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/perf/jsperf.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,133 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef perf_jsperf_h
1.10 +#define perf_jsperf_h
1.11 +
1.12 +#include "jstypes.h"
1.13 +
1.14 +#include "js/TypeDecls.h"
1.15 +#include "js/Utility.h"
1.16 +
1.17 +namespace JS {
1.18 +
1.19 +/*
1.20 + * JS::PerfMeasurement is a generic way to access detailed performance
1.21 + * measurement APIs provided by your operating system. The details of
1.22 + * exactly how this works and what can be measured are highly
1.23 + * system-specific, but this interface is (one hopes) implementable
1.24 + * on top of all of them.
1.25 + *
1.26 + * To use this API, create a PerfMeasurement object, passing its
1.27 + * constructor a bitmask indicating which events you are interested
1.28 + * in. Thereafter, Start() zeroes all counters and starts timing;
1.29 + * Stop() stops timing again; and the counters for the events you
1.30 + * requested are available as data values after calling Stop(). The
1.31 + * object may be reused for many measurements.
1.32 + */
1.33 +class JS_FRIEND_API(PerfMeasurement)
1.34 +{
1.35 + protected:
1.36 + // Implementation-specific data, if any.
1.37 + void* impl;
1.38 +
1.39 + public:
1.40 + /*
1.41 + * Events that may be measured. Taken directly from the list of
1.42 + * "generalized hardware performance event types" in the Linux
1.43 + * perf_event API, plus some of the "software events".
1.44 + */
1.45 + enum EventMask {
1.46 + CPU_CYCLES = 0x00000001,
1.47 + INSTRUCTIONS = 0x00000002,
1.48 + CACHE_REFERENCES = 0x00000004,
1.49 + CACHE_MISSES = 0x00000008,
1.50 + BRANCH_INSTRUCTIONS = 0x00000010,
1.51 + BRANCH_MISSES = 0x00000020,
1.52 + BUS_CYCLES = 0x00000040,
1.53 + PAGE_FAULTS = 0x00000080,
1.54 + MAJOR_PAGE_FAULTS = 0x00000100,
1.55 + CONTEXT_SWITCHES = 0x00000200,
1.56 + CPU_MIGRATIONS = 0x00000400,
1.57 +
1.58 + ALL = 0x000007ff,
1.59 + NUM_MEASURABLE_EVENTS = 11
1.60 + };
1.61 +
1.62 + /*
1.63 + * Bitmask of events that will be measured when this object is
1.64 + * active (between Start() and Stop()). This may differ from the
1.65 + * bitmask passed to the constructor if the platform does not
1.66 + * support measuring all of the requested events.
1.67 + */
1.68 + const EventMask eventsMeasured;
1.69 +
1.70 + /*
1.71 + * Counters for each measurable event.
1.72 + * Immediately after one of these objects is created, all of the
1.73 + * counters for enabled events will be zero, and all of the
1.74 + * counters for disabled events will be uint64_t(-1).
1.75 + */
1.76 + uint64_t cpu_cycles;
1.77 + uint64_t instructions;
1.78 + uint64_t cache_references;
1.79 + uint64_t cache_misses;
1.80 + uint64_t branch_instructions;
1.81 + uint64_t branch_misses;
1.82 + uint64_t bus_cycles;
1.83 + uint64_t page_faults;
1.84 + uint64_t major_page_faults;
1.85 + uint64_t context_switches;
1.86 + uint64_t cpu_migrations;
1.87 +
1.88 + /*
1.89 + * Prepare to measure the indicated set of events. If not all of
1.90 + * the requested events can be measured on the current platform,
1.91 + * then the eventsMeasured bitmask will only include the subset of
1.92 + * |toMeasure| corresponding to the events that can be measured.
1.93 + */
1.94 + PerfMeasurement(EventMask toMeasure);
1.95 +
1.96 + /* Done with this set of measurements, tear down OS-level state. */
1.97 + ~PerfMeasurement();
1.98 +
1.99 + /* Start a measurement cycle. */
1.100 + void start();
1.101 +
1.102 + /*
1.103 + * End a measurement cycle, and for each enabled counter, add the
1.104 + * number of measured events of that type to the appropriate
1.105 + * visible variable.
1.106 + */
1.107 + void stop();
1.108 +
1.109 + /* Reset all enabled counters to zero. */
1.110 + void reset();
1.111 +
1.112 + /*
1.113 + * True if this platform supports measuring _something_, i.e. it's
1.114 + * not using the stub implementation.
1.115 + */
1.116 + static bool canMeasureSomething();
1.117 +};
1.118 +
1.119 +/* Inject a Javascript wrapper around the above C++ class into the
1.120 + * Javascript object passed as an argument (this will normally be a
1.121 + * global object). The JS-visible API is identical to the C++ API.
1.122 + */
1.123 +extern JS_FRIEND_API(JSObject*)
1.124 + RegisterPerfMeasurement(JSContext *cx, JS::HandleObject global);
1.125 +
1.126 +/*
1.127 + * Given a Value which contains an instance of the aforementioned
1.128 + * wrapper class, extract the C++ object. Returns nullptr if the
1.129 + * Value is not an instance of the wrapper.
1.130 + */
1.131 +extern JS_FRIEND_API(PerfMeasurement*)
1.132 + ExtractPerfMeasurement(Value wrapper);
1.133 +
1.134 +} // namespace JS
1.135 +
1.136 +#endif /* perf_jsperf_h */
