src/third_party/mozjs-45/js/src/perf/pm_linux.cpp - cobalt - Git at Google

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 /* This variant of nsIPerfMeasurement uses the perf_event interface
  * added in Linux 2.6.31.  We key compilation of this file off the
  * existence of <linux/perf_event.h>.
  */

 #include <errno.h>
 #include <linux/perf_event.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <sys/syscall.h>
 #include <unistd.h>

 #include "perf/jsperf.h"

 using namespace js;

 // As of July 2010, this system call has not been added to the
 // C library, so we have to provide our own wrapper function.
 // If this code runs on a kernel that does not implement the
 // system call (2.6.30 or older) nothing unpredictable will
 // happen - it will just always fail and return -1.
 static int
 sys_perf_event_open(struct perf_event_attr* attr, pid_t pid, int cpu,
                     int group_fd, unsigned long flags)
 {
     return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
 }

 namespace {

 using JS::PerfMeasurement;
 typedef PerfMeasurement::EventMask EventMask;

 // Additional state required by this implementation.
 struct Impl
 {
     // Each active counter corresponds to an open file descriptor.
     int f_cpu_cycles;
     int f_instructions;
     int f_cache_references;
     int f_cache_misses;
     int f_branch_instructions;
     int f_branch_misses;
     int f_bus_cycles;
     int f_page_faults;
     int f_major_page_faults;
     int f_context_switches;
     int f_cpu_migrations;

     // Counter group leader, for Start and Stop.
     int group_leader;

     // Whether counters are running.
     bool running;

     Impl();
     ~Impl();

     EventMask init(EventMask toMeasure);
     void start();
     void stop(PerfMeasurement* counters);
 };

 // Mapping from our event bitmask to codes passed into the kernel, and
 // to fields in the PerfMeasurement and PerfMeasurement::impl structures.
 static const struct
 {
     EventMask bit;
     uint32_t type;
     uint32_t config;
     uint64_t PerfMeasurement::* counter;
     int Impl::* fd;
 } kSlots[PerfMeasurement::NUM_MEASURABLE_EVENTS] = {
 #define HW(mask, constant, fieldname)                                   \
     { PerfMeasurement::mask, PERF_TYPE_HARDWARE, PERF_COUNT_HW_##constant, \
       &PerfMeasurement::fieldname, &Impl::f_##fieldname }
 #define SW(mask, constant, fieldname)                                   \
     { PerfMeasurement::mask, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_##constant, \
       &PerfMeasurement::fieldname, &Impl::f_##fieldname }

     HW(CPU_CYCLES,          CPU_CYCLES,          cpu_cycles),
     HW(INSTRUCTIONS,        INSTRUCTIONS,        instructions),
     HW(CACHE_REFERENCES,    CACHE_REFERENCES,    cache_references),
     HW(CACHE_MISSES,        CACHE_MISSES,        cache_misses),
     HW(BRANCH_INSTRUCTIONS, BRANCH_INSTRUCTIONS, branch_instructions),
     HW(BRANCH_MISSES,       BRANCH_MISSES,       branch_misses),
     HW(BUS_CYCLES,          BUS_CYCLES,          bus_cycles),
     SW(PAGE_FAULTS,         PAGE_FAULTS,         page_faults),
     SW(MAJOR_PAGE_FAULTS,   PAGE_FAULTS_MAJ,     major_page_faults),
     SW(CONTEXT_SWITCHES,    CONTEXT_SWITCHES,    context_switches),
     SW(CPU_MIGRATIONS,      CPU_MIGRATIONS,      cpu_migrations),

 #undef HW
 #undef SW
 };

 Impl::Impl()
   : f_cpu_cycles(-1),
     f_instructions(-1),
     f_cache_references(-1),
     f_cache_misses(-1),
     f_branch_instructions(-1),
     f_branch_misses(-1),
     f_bus_cycles(-1),
     f_page_faults(-1),
     f_major_page_faults(-1),
     f_context_switches(-1),
     f_cpu_migrations(-1),
     group_leader(-1),
     running(false)
 {
 }

 Impl::~Impl()
 {
     // Close all active counter descriptors.  Take care to do the group
     // leader last (this may not be necessary, but it's unclear what
     // happens if you close the group leader out from under a group).
     for (int i = 0; i < PerfMeasurement::NUM_MEASURABLE_EVENTS; i++) {
         int fd = this->*(kSlots[i].fd);
         if (fd != -1 && fd != group_leader)
             close(fd);
     }

     if (group_leader != -1)
         close(group_leader);
 }

 EventMask
 Impl::init(EventMask toMeasure)
 {
     MOZ_ASSERT(group_leader == -1);
     if (!toMeasure)
         return EventMask(0);

     EventMask measured = EventMask(0);
     struct perf_event_attr attr;
     for (int i = 0; i < PerfMeasurement::NUM_MEASURABLE_EVENTS; i++) {
         if (!(toMeasure & kSlots[i].bit))
             continue;

         memset(&attr, 0, sizeof(attr));
         attr.size = sizeof(attr);

         // Set the type and config fields to indicate the counter we
         // want to enable.  We want read format 0, and we're not using
         // sampling, so leave those fields unset.
         attr.type = kSlots[i].type;
         attr.config = kSlots[i].config;

         // If this will be the group leader it should start off
         // disabled.  Otherwise it should start off enabled (but blocked
         // on the group leader).
         if (group_leader == -1)
             attr.disabled = 1;

         // The rest of the bit fields are really poorly documented.
         // For instance, I have *no idea* whether we should be setting
         // the inherit, inherit_stat, or task flags.  I'm pretty sure
         // we do want to set mmap and comm, and not any of the ones I
         // haven't mentioned.
         attr.mmap = 1;
         attr.comm = 1;

         int fd = sys_perf_event_open(&attr,
                                      0 /* trace self */,
                                      -1 /* on any cpu */,
                                      group_leader,
                                      0 /* no flags presently defined */);
         if (fd == -1)
             continue;

         measured = EventMask(measured | kSlots[i].bit);
         this->*(kSlots[i].fd) = fd;
         if (group_leader == -1)
             group_leader = fd;
     }
     return measured;
 }

 void
 Impl::start()
 {
     if (running || group_leader == -1)
         return;

     running = true;
     ioctl(group_leader, PERF_EVENT_IOC_ENABLE, 0);
 }

 void
 Impl::stop(PerfMeasurement* counters)
 {
     // This scratch buffer is to ensure that we have read all the
     // available data, even if that's more than we expect.
     unsigned char buf[1024];

     if (!running || group_leader == -1)
         return;

     ioctl(group_leader, PERF_EVENT_IOC_DISABLE, 0);
     running = false;

     // read out and reset all the counter values
     for (int i = 0; i < PerfMeasurement::NUM_MEASURABLE_EVENTS; i++) {
         int fd = this->*(kSlots[i].fd);
         if (fd == -1)
             continue;

         if (read(fd, buf, sizeof(buf)) == sizeof(uint64_t)) {
             uint64_t cur;
             memcpy(&cur, buf, sizeof(uint64_t));
             counters->*(kSlots[i].counter) += cur;
         }

         // Reset the counter regardless of whether the read did what
         // we expected.
         ioctl(fd, PERF_EVENT_IOC_RESET, 0);
     }
 }

 } // namespace


 namespace JS {

 #define initCtr(flag) ((eventsMeasured & flag) ? 0 : -1)

 PerfMeasurement::PerfMeasurement(PerfMeasurement::EventMask toMeasure)
   : impl(js_new<Impl>()),
     eventsMeasured(impl ? static_cast<Impl*>(impl)->init(toMeasure)
                    : EventMask(0)),
     cpu_cycles(initCtr(CPU_CYCLES)),
     instructions(initCtr(INSTRUCTIONS)),
     cache_references(initCtr(CACHE_REFERENCES)),
     cache_misses(initCtr(CACHE_MISSES)),
     branch_instructions(initCtr(BRANCH_INSTRUCTIONS)),
     branch_misses(initCtr(BRANCH_MISSES)),
     bus_cycles(initCtr(BUS_CYCLES)),
     page_faults(initCtr(PAGE_FAULTS)),
     major_page_faults(initCtr(MAJOR_PAGE_FAULTS)),
     context_switches(initCtr(CONTEXT_SWITCHES)),
     cpu_migrations(initCtr(CPU_MIGRATIONS))
 {
 }

 #undef initCtr

 PerfMeasurement::~PerfMeasurement()
 {
     js_delete(static_cast<Impl*>(impl));
 }

 void
 PerfMeasurement::start()
 {
     if (impl)
         static_cast<Impl*>(impl)->start();
 }

 void
 PerfMeasurement::stop()
 {
     if (impl)
         static_cast<Impl*>(impl)->stop(this);
 }

 void
 PerfMeasurement::reset()
 {
     for (int i = 0; i < NUM_MEASURABLE_EVENTS; i++) {
         if (eventsMeasured & kSlots[i].bit)
             this->*(kSlots[i].counter) = 0;
         else
             this->*(kSlots[i].counter) = -1;
     }
 }

 bool
 PerfMeasurement::canMeasureSomething()
 {
     // Find out if the kernel implements the performance measurement
     // API.  If it doesn't, syscall(__NR_perf_event_open, ...) is
     // guaranteed to return -1 and set errno to ENOSYS.
     //
     // We set up input parameters that should provoke an EINVAL error
     // from a kernel that does implement perf_event_open, but we can't
     // be sure it will (newer kernels might add more event types), so
     // we have to take care to close any valid fd it might return.

     struct perf_event_attr attr;
     memset(&attr, 0, sizeof(attr));
     attr.size = sizeof(attr);
     attr.type = PERF_TYPE_MAX;

     int fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
     if (fd >= 0) {
         close(fd);
         return true;
     } else {
         return errno != ENOSYS;
     }
 }

 } // namespace JS
	/* -- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -- */
	/* This Source Code Form is subject to the terms of the Mozilla Public
	* License, v. 2.0. If a copy of the MPL was not distributed with this
	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

	/* This variant of nsIPerfMeasurement uses the perf_event interface
	* added in Linux 2.6.31. We key compilation of this file off the
	* existence of <linux/perf_event.h>.
	*/

	#include <errno.h>
	#include <linux/perf_event.h>
	#include <string.h>
	#include <sys/ioctl.h>
	#include <sys/syscall.h>
	#include <unistd.h>

	#include "perf/jsperf.h"

	using namespace js;

	// As of July 2010, this system call has not been added to the
	// C library, so we have to provide our own wrapper function.
	// If this code runs on a kernel that does not implement the
	// system call (2.6.30 or older) nothing unpredictable will
	// happen - it will just always fail and return -1.
	static int
	sys_perf_event_open(struct perf_event_attr* attr, pid_t pid, int cpu,
	int group_fd, unsigned long flags)
	{
	return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
	}

	namespace {

	using JS::PerfMeasurement;
	typedef PerfMeasurement::EventMask EventMask;

	// Additional state required by this implementation.
	struct Impl
	{
	// Each active counter corresponds to an open file descriptor.
	int f_cpu_cycles;
	int f_instructions;
	int f_cache_references;
	int f_cache_misses;
	int f_branch_instructions;
	int f_branch_misses;
	int f_bus_cycles;
	int f_page_faults;
	int f_major_page_faults;
	int f_context_switches;
	int f_cpu_migrations;

	// Counter group leader, for Start and Stop.
	int group_leader;

	// Whether counters are running.
	bool running;

	Impl();
	~Impl();

	EventMask init(EventMask toMeasure);
	void start();
	void stop(PerfMeasurement* counters);
	};

	// Mapping from our event bitmask to codes passed into the kernel, and
	// to fields in the PerfMeasurement and PerfMeasurement::impl structures.
	static const struct
	{
	EventMask bit;
	uint32_t type;
	uint32_t config;
	uint64_t PerfMeasurement::* counter;
	int Impl::* fd;
	} kSlots[PerfMeasurement::NUM_MEASURABLE_EVENTS] = {
	#define HW(mask, constant, fieldname) \
	{ PerfMeasurement::mask, PERF_TYPE_HARDWARE, PERF_COUNT_HW_##constant, \
	&PerfMeasurement::fieldname, &Impl::f_##fieldname }
	#define SW(mask, constant, fieldname) \
	{ PerfMeasurement::mask, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_##constant, \
	&PerfMeasurement::fieldname, &Impl::f_##fieldname }

	HW(CPU_CYCLES, CPU_CYCLES, cpu_cycles),
	HW(INSTRUCTIONS, INSTRUCTIONS, instructions),
	HW(CACHE_REFERENCES, CACHE_REFERENCES, cache_references),
	HW(CACHE_MISSES, CACHE_MISSES, cache_misses),
	HW(BRANCH_INSTRUCTIONS, BRANCH_INSTRUCTIONS, branch_instructions),
	HW(BRANCH_MISSES, BRANCH_MISSES, branch_misses),
	HW(BUS_CYCLES, BUS_CYCLES, bus_cycles),
	SW(PAGE_FAULTS, PAGE_FAULTS, page_faults),
	SW(MAJOR_PAGE_FAULTS, PAGE_FAULTS_MAJ, major_page_faults),
	SW(CONTEXT_SWITCHES, CONTEXT_SWITCHES, context_switches),
	SW(CPU_MIGRATIONS, CPU_MIGRATIONS, cpu_migrations),

	#undef HW
	#undef SW
	};

	Impl::Impl()
	: f_cpu_cycles(-1),
	f_instructions(-1),
	f_cache_references(-1),
	f_cache_misses(-1),
	f_branch_instructions(-1),
	f_branch_misses(-1),
	f_bus_cycles(-1),
	f_page_faults(-1),
	f_major_page_faults(-1),
	f_context_switches(-1),
	f_cpu_migrations(-1),
	group_leader(-1),
	running(false)
	{
	}

	Impl::~Impl()
	{
	// Close all active counter descriptors. Take care to do the group
	// leader last (this may not be necessary, but it's unclear what
	// happens if you close the group leader out from under a group).
	for (int i = 0; i < PerfMeasurement::NUM_MEASURABLE_EVENTS; i++) {
	int fd = this->*(kSlots[i].fd);
	if (fd != -1 && fd != group_leader)
	close(fd);
	}

	if (group_leader != -1)
	close(group_leader);
	}

	EventMask
	Impl::init(EventMask toMeasure)
	{
	MOZ_ASSERT(group_leader == -1);
	if (!toMeasure)
	return EventMask(0);

	EventMask measured = EventMask(0);
	struct perf_event_attr attr;
	for (int i = 0; i < PerfMeasurement::NUM_MEASURABLE_EVENTS; i++) {
	if (!(toMeasure & kSlots[i].bit))
	continue;

	memset(&attr, 0, sizeof(attr));
	attr.size = sizeof(attr);

	// Set the type and config fields to indicate the counter we
	// want to enable. We want read format 0, and we're not using
	// sampling, so leave those fields unset.
	attr.type = kSlots[i].type;
	attr.config = kSlots[i].config;

	// If this will be the group leader it should start off
	// disabled. Otherwise it should start off enabled (but blocked
	// on the group leader).
	if (group_leader == -1)
	attr.disabled = 1;

	// The rest of the bit fields are really poorly documented.
	// For instance, I have no idea whether we should be setting
	// the inherit, inherit_stat, or task flags. I'm pretty sure
	// we do want to set mmap and comm, and not any of the ones I
	// haven't mentioned.
	attr.mmap = 1;
	attr.comm = 1;

	int fd = sys_perf_event_open(&attr,
	0 /* trace self */,
	-1 /* on any cpu */,
	group_leader,
	0 /* no flags presently defined */);
	if (fd == -1)
	continue;

	measured = EventMask(measured \| kSlots[i].bit);
	this->*(kSlots[i].fd) = fd;
	if (group_leader == -1)
	group_leader = fd;
	}
	return measured;
	}

	void
	Impl::start()
	{
	if (running \|\| group_leader == -1)
	return;

	running = true;
	ioctl(group_leader, PERF_EVENT_IOC_ENABLE, 0);
	}

	void
	Impl::stop(PerfMeasurement* counters)
	{
	// This scratch buffer is to ensure that we have read all the
	// available data, even if that's more than we expect.
	unsigned char buf[1024];

	if (!running \|\| group_leader == -1)
	return;

	ioctl(group_leader, PERF_EVENT_IOC_DISABLE, 0);
	running = false;

	// read out and reset all the counter values
	for (int i = 0; i < PerfMeasurement::NUM_MEASURABLE_EVENTS; i++) {
	int fd = this->*(kSlots[i].fd);
	if (fd == -1)
	continue;

	if (read(fd, buf, sizeof(buf)) == sizeof(uint64_t)) {
	uint64_t cur;
	memcpy(&cur, buf, sizeof(uint64_t));
	counters->*(kSlots[i].counter) += cur;
	}

	// Reset the counter regardless of whether the read did what
	// we expected.
	ioctl(fd, PERF_EVENT_IOC_RESET, 0);
	}
	}

	} // namespace


	namespace JS {

	#define initCtr(flag) ((eventsMeasured & flag) ? 0 : -1)

	PerfMeasurement::PerfMeasurement(PerfMeasurement::EventMask toMeasure)
	: impl(js_new<Impl>()),
	eventsMeasured(impl ? static_cast<Impl*>(impl)->init(toMeasure)
	: EventMask(0)),
	cpu_cycles(initCtr(CPU_CYCLES)),
	instructions(initCtr(INSTRUCTIONS)),
	cache_references(initCtr(CACHE_REFERENCES)),
	cache_misses(initCtr(CACHE_MISSES)),
	branch_instructions(initCtr(BRANCH_INSTRUCTIONS)),
	branch_misses(initCtr(BRANCH_MISSES)),
	bus_cycles(initCtr(BUS_CYCLES)),
	page_faults(initCtr(PAGE_FAULTS)),
	major_page_faults(initCtr(MAJOR_PAGE_FAULTS)),
	context_switches(initCtr(CONTEXT_SWITCHES)),
	cpu_migrations(initCtr(CPU_MIGRATIONS))
	{
	}

	#undef initCtr

	PerfMeasurement::~PerfMeasurement()
	{
	js_delete(static_cast<Impl*>(impl));
	}

	void
	PerfMeasurement::start()
	{
	if (impl)
	static_cast<Impl*>(impl)->start();
	}

	void
	PerfMeasurement::stop()
	{
	if (impl)
	static_cast<Impl*>(impl)->stop(this);
	}

	void
	PerfMeasurement::reset()
	{
	for (int i = 0; i < NUM_MEASURABLE_EVENTS; i++) {
	if (eventsMeasured & kSlots[i].bit)
	this->*(kSlots[i].counter) = 0;
	else
	this->*(kSlots[i].counter) = -1;
	}
	}

	bool
	PerfMeasurement::canMeasureSomething()
	{
	// Find out if the kernel implements the performance measurement
	// API. If it doesn't, syscall(__NR_perf_event_open, ...) is
	// guaranteed to return -1 and set errno to ENOSYS.
	//
	// We set up input parameters that should provoke an EINVAL error
	// from a kernel that does implement perf_event_open, but we can't
	// be sure it will (newer kernels might add more event types), so
	// we have to take care to close any valid fd it might return.

	struct perf_event_attr attr;
	memset(&attr, 0, sizeof(attr));
	attr.size = sizeof(attr);
	attr.type = PERF_TYPE_MAX;

	int fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
	if (fd >= 0) {
	close(fd);
	return true;
	} else {
	return errno != ENOSYS;
	}
	}

	} // namespace JS