gecko-dev/tools/profiler/platform-linux.cc

657 lines
19 KiB
C++

// Copyright (c) 2006-2011 The Chromium Authors. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google, Inc. nor the names of its contributors
// may be used to endorse or promote products derived from this
// software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
/*
# vim: sw=2
*/
#include <stdio.h>
#include <math.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/prctl.h> // set name
#include <stdlib.h>
#include <sched.h>
#ifdef ANDROID
#include <android/log.h>
#else
#define __android_log_print(a, ...)
#endif
#include <ucontext.h>
// Ubuntu Dapper requires memory pages to be marked as
// executable. Otherwise, OS raises an exception when executing code
// in that page.
#include <sys/types.h> // mmap & munmap
#include <sys/mman.h> // mmap & munmap
#include <sys/stat.h> // open
#include <fcntl.h> // open
#include <unistd.h> // sysconf
#include <semaphore.h>
#ifdef __GLIBC__
#include <execinfo.h> // backtrace, backtrace_symbols
#endif // def __GLIBC__
#include <strings.h> // index
#include <errno.h>
#include <stdarg.h>
#include "platform.h"
#include "GeckoProfiler.h"
#include "mozilla/Mutex.h"
#include "mozilla/Atomics.h"
#include "mozilla/LinuxSignal.h"
#include "ProfileEntry.h"
#include "nsThreadUtils.h"
#include "TableTicker.h"
#include "ThreadResponsiveness.h"
#include "UnwinderThread2.h"
#if defined(__ARM_EABI__) && defined(MOZ_WIDGET_GONK)
// Should also work on other Android and ARM Linux, but not tested there yet.
#define USE_EHABI_STACKWALK
#include "EHABIStackWalk.h"
#endif
// Memory profile
#include "nsMemoryReporterManager.h"
#include <string.h>
#include <stdio.h>
#include <list>
#ifdef MOZ_NUWA_PROCESS
#include "ipc/Nuwa.h"
#endif
#define SIGNAL_SAVE_PROFILE SIGUSR2
#if defined(__GLIBC__)
// glibc doesn't implement gettid(2).
#include <sys/syscall.h>
pid_t gettid()
{
return (pid_t) syscall(SYS_gettid);
}
#endif
/* static */ Thread::tid_t
Thread::GetCurrentId()
{
return gettid();
}
#if !defined(ANDROID)
// Keep track of when any of our threads calls fork(), so we can
// temporarily disable signal delivery during the fork() call. Not
// doing so appears to cause a kind of race, in which signals keep
// getting delivered to the thread doing fork(), which keeps causing
// it to fail and be restarted; hence forward progress is delayed a
// great deal. A side effect of this is to permanently disable
// sampling in the child process. See bug 837390.
// Unfortunately this is only doable on non-Android, since Bionic
// doesn't have pthread_atfork.
// This records the current state at the time we paused it.
static bool was_paused = false;
// In the parent, just before the fork, record the pausedness state,
// and then pause.
static void paf_prepare(void) {
if (Sampler::GetActiveSampler()) {
was_paused = Sampler::GetActiveSampler()->IsPaused();
Sampler::GetActiveSampler()->SetPaused(true);
} else {
was_paused = false;
}
}
// In the parent, just after the fork, return pausedness to the
// pre-fork state.
static void paf_parent(void) {
if (Sampler::GetActiveSampler())
Sampler::GetActiveSampler()->SetPaused(was_paused);
}
// Set up the fork handlers.
static void* setup_atfork() {
pthread_atfork(paf_prepare, paf_parent, NULL);
return NULL;
}
#endif /* !defined(ANDROID) */
struct SamplerRegistry {
static void AddActiveSampler(Sampler *sampler) {
ASSERT(!SamplerRegistry::sampler);
SamplerRegistry::sampler = sampler;
}
static void RemoveActiveSampler(Sampler *sampler) {
SamplerRegistry::sampler = NULL;
}
static Sampler *sampler;
};
Sampler *SamplerRegistry::sampler = NULL;
static mozilla::Atomic<ThreadProfile*> sCurrentThreadProfile;
static sem_t sSignalHandlingDone;
static void ProfilerSaveSignalHandler(int signal, siginfo_t* info, void* context) {
Sampler::GetActiveSampler()->RequestSave();
}
static void SetSampleContext(TickSample* sample, void* context)
{
// Extracting the sample from the context is extremely machine dependent.
ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
mcontext_t& mcontext = ucontext->uc_mcontext;
#if V8_HOST_ARCH_IA32
sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
#elif V8_HOST_ARCH_X64
sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
#elif V8_HOST_ARCH_ARM
// An undefined macro evaluates to 0, so this applies to Android's Bionic also.
#if !defined(ANDROID) && (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
sample->pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
sample->sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
sample->fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
#ifdef ENABLE_ARM_LR_SAVING
sample->lr = reinterpret_cast<Address>(mcontext.gregs[R14]);
#endif
#else
sample->pc = reinterpret_cast<Address>(mcontext.arm_pc);
sample->sp = reinterpret_cast<Address>(mcontext.arm_sp);
sample->fp = reinterpret_cast<Address>(mcontext.arm_fp);
#ifdef ENABLE_ARM_LR_SAVING
sample->lr = reinterpret_cast<Address>(mcontext.arm_lr);
#endif
#endif
#elif V8_HOST_ARCH_MIPS
// Implement this on MIPS.
UNIMPLEMENTED();
#endif
}
#ifdef ANDROID
#define V8_HOST_ARCH_ARM 1
#define SYS_gettid __NR_gettid
#define SYS_tgkill __NR_tgkill
#else
#define V8_HOST_ARCH_X64 1
#endif
namespace {
void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
if (!Sampler::GetActiveSampler()) {
sem_post(&sSignalHandlingDone);
return;
}
TickSample sample_obj;
TickSample* sample = &sample_obj;
sample->context = context;
// If profiling, we extract the current pc and sp.
if (Sampler::GetActiveSampler()->IsProfiling()) {
SetSampleContext(sample, context);
}
sample->threadProfile = sCurrentThreadProfile;
sample->timestamp = mozilla::TimeStamp::Now();
sample->rssMemory = sample->threadProfile->mRssMemory;
sample->ussMemory = sample->threadProfile->mUssMemory;
Sampler::GetActiveSampler()->Tick(sample);
sCurrentThreadProfile = NULL;
sem_post(&sSignalHandlingDone);
}
} // namespace
static void ProfilerSignalThread(ThreadProfile *profile,
bool isFirstProfiledThread)
{
if (isFirstProfiledThread && Sampler::GetActiveSampler()->ProfileMemory()) {
profile->mRssMemory = nsMemoryReporterManager::ResidentFast();
profile->mUssMemory = nsMemoryReporterManager::ResidentUnique();
} else {
profile->mRssMemory = 0;
profile->mUssMemory = 0;
}
}
// If the Nuwa process is enabled, we need to use the wrapper of tgkill() to
// perform the mapping of thread ID.
#ifdef MOZ_NUWA_PROCESS
extern "C" MFBT_API int tgkill(pid_t tgid, pid_t tid, int signalno);
#else
int tgkill(pid_t tgid, pid_t tid, int signalno) {
return syscall(SYS_tgkill, tgid, tid, signalno);
}
#endif
class PlatformData : public Malloced {
public:
PlatformData()
{}
};
/* static */ PlatformData*
Sampler::AllocPlatformData(int aThreadId)
{
return new PlatformData;
}
/* static */ void
Sampler::FreePlatformData(PlatformData* aData)
{
delete aData;
}
static void* SignalSender(void* arg) {
// Taken from platform_thread_posix.cc
prctl(PR_SET_NAME, "SamplerThread", 0, 0, 0);
#ifdef MOZ_NUWA_PROCESS
// If the Nuwa process is enabled, we need to mark and freeze the sampler
// thread in the Nuwa process and have this thread recreated in the spawned
// child.
if(IsNuwaProcess()) {
NuwaMarkCurrentThread(nullptr, nullptr);
// Freeze the thread here so the spawned child will get the correct tgid
// from the getpid() call below.
NuwaFreezeCurrentThread();
}
#endif
int vm_tgid_ = getpid();
while (SamplerRegistry::sampler->IsActive()) {
SamplerRegistry::sampler->HandleSaveRequest();
if (!SamplerRegistry::sampler->IsPaused()) {
mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
std::vector<ThreadInfo*> threads =
SamplerRegistry::sampler->GetRegisteredThreads();
bool isFirstProfiledThread = true;
for (uint32_t i = 0; i < threads.size(); i++) {
ThreadInfo* info = threads[i];
// This will be null if we're not interested in profiling this thread.
if (!info->Profile())
continue;
PseudoStack::SleepState sleeping = info->Stack()->observeSleeping();
if (sleeping == PseudoStack::SLEEPING_AGAIN) {
info->Profile()->DuplicateLastSample();
//XXX: This causes flushes regardless of jank-only mode
info->Profile()->flush();
continue;
}
info->Profile()->GetThreadResponsiveness()->Update();
// We use sCurrentThreadProfile the ThreadProfile for the
// thread we're profiling to the signal handler
sCurrentThreadProfile = info->Profile();
int threadId = info->ThreadId();
// Profile from the signal sender for information which is not signal
// safe, and will have low variation between the emission of the signal
// and the signal handler catch.
ProfilerSignalThread(sCurrentThreadProfile, isFirstProfiledThread);
// Profile from the signal handler for information which is signal safe
// and needs to be precise too, such as the stack of the interrupted
// thread.
if (tgkill(vm_tgid_, threadId, SIGPROF) != 0) {
printf_stderr("profiler failed to signal tid=%d\n", threadId);
#ifdef DEBUG
abort();
#endif
continue;
}
// Wait for the signal handler to run before moving on to the next one
sem_wait(&sSignalHandlingDone);
isFirstProfiledThread = false;
}
}
// Convert ms to us and subtract 100 us to compensate delays
// occuring during signal delivery.
// TODO measure and confirm this.
int interval = floor(SamplerRegistry::sampler->interval() * 1000 + 0.5) - 100;
if (interval <= 0) {
interval = 1;
}
OS::SleepMicro(interval);
}
return 0;
}
Sampler::Sampler(double interval, bool profiling, int entrySize)
: interval_(interval),
profiling_(profiling),
paused_(false),
active_(false),
entrySize_(entrySize) {
}
Sampler::~Sampler() {
ASSERT(!signal_sender_launched_);
}
void Sampler::Start() {
LOG("Sampler started");
#ifdef USE_EHABI_STACKWALK
mozilla::EHABIStackWalkInit();
#endif
SamplerRegistry::AddActiveSampler(this);
// Initialize signal handler communication
sCurrentThreadProfile = NULL;
if (sem_init(&sSignalHandlingDone, /* pshared: */ 0, /* value: */ 0) != 0) {
LOG("Error initializing semaphore");
return;
}
// Request profiling signals.
LOG("Request signal");
struct sigaction sa;
sa.sa_sigaction = MOZ_SIGNAL_TRAMPOLINE(ProfilerSignalHandler);
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART | SA_SIGINFO;
if (sigaction(SIGPROF, &sa, &old_sigprof_signal_handler_) != 0) {
LOG("Error installing signal");
return;
}
// Request save profile signals
struct sigaction sa2;
sa2.sa_sigaction = ProfilerSaveSignalHandler;
sigemptyset(&sa2.sa_mask);
sa2.sa_flags = SA_RESTART | SA_SIGINFO;
if (sigaction(SIGNAL_SAVE_PROFILE, &sa2, &old_sigsave_signal_handler_) != 0) {
LOG("Error installing start signal");
return;
}
LOG("Signal installed");
signal_handler_installed_ = true;
// Start a thread that sends SIGPROF signal to VM thread.
// Sending the signal ourselves instead of relying on itimer provides
// much better accuracy.
SetActive(true);
if (pthread_create(
&signal_sender_thread_, NULL, SignalSender, NULL) == 0) {
signal_sender_launched_ = true;
}
LOG("Profiler thread started");
}
void Sampler::Stop() {
SetActive(false);
// Wait for signal sender termination (it will exit after setting
// active_ to false).
if (signal_sender_launched_) {
pthread_join(signal_sender_thread_, NULL);
signal_sender_launched_ = false;
}
SamplerRegistry::RemoveActiveSampler(this);
// Restore old signal handler
if (signal_handler_installed_) {
sigaction(SIGNAL_SAVE_PROFILE, &old_sigsave_signal_handler_, 0);
sigaction(SIGPROF, &old_sigprof_signal_handler_, 0);
signal_handler_installed_ = false;
}
}
bool Sampler::RegisterCurrentThread(const char* aName,
PseudoStack* aPseudoStack,
bool aIsMainThread, void* stackTop)
{
if (!Sampler::sRegisteredThreadsMutex)
return false;
mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
int id = gettid();
for (uint32_t i = 0; i < sRegisteredThreads->size(); i++) {
ThreadInfo* info = sRegisteredThreads->at(i);
if (info->ThreadId() == id) {
// Thread already registered. This means the first unregister will be
// too early.
ASSERT(false);
return false;
}
}
set_tls_stack_top(stackTop);
ThreadInfo* info = new ThreadInfo(aName, id,
aIsMainThread, aPseudoStack, stackTop);
if (sActiveSampler) {
sActiveSampler->RegisterThread(info);
}
sRegisteredThreads->push_back(info);
uwt__register_thread_for_profiling(stackTop);
return true;
}
void Sampler::UnregisterCurrentThread()
{
if (!Sampler::sRegisteredThreadsMutex)
return;
tlsStackTop.set(nullptr);
mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
int id = gettid();
for (uint32_t i = 0; i < sRegisteredThreads->size(); i++) {
ThreadInfo* info = sRegisteredThreads->at(i);
if (info->ThreadId() == id) {
delete info;
sRegisteredThreads->erase(sRegisteredThreads->begin() + i);
break;
}
}
uwt__unregister_thread_for_profiling();
}
#ifdef ANDROID
static struct sigaction old_sigstart_signal_handler;
const int SIGSTART = SIGUSR2;
static void freeArray(const char** array, int size) {
for (int i = 0; i < size; i++) {
free((void*) array[i]);
}
}
static uint32_t readCSVArray(char* csvList, const char** buffer) {
uint32_t count;
char* savePtr;
int newlinePos = strlen(csvList) - 1;
if (csvList[newlinePos] == '\n') {
csvList[newlinePos] = '\0';
}
char* item = strtok_r(csvList, ",", &savePtr);
for (count = 0; item; item = strtok_r(NULL, ",", &savePtr)) {
int length = strlen(item) + 1; // Include \0
char* newBuf = (char*) malloc(sizeof(char) * length);
buffer[count] = newBuf;
strncpy(newBuf, item, length);
count++;
}
return count;
}
// Currently support only the env variables
// reported in read_profiler_env
static void ReadProfilerVars(const char* fileName, const char** features,
uint32_t* featureCount, const char** threadNames, uint32_t* threadCount) {
FILE* file = fopen(fileName, "r");
const int bufferSize = 1024;
char line[bufferSize];
char* feature;
char* value;
char* savePtr;
if (file) {
while (fgets(line, bufferSize, file) != NULL) {
feature = strtok_r(line, "=", &savePtr);
value = strtok_r(NULL, "", &savePtr);
if (strncmp(feature, PROFILER_MODE, bufferSize) == 0) {
set_profiler_mode(value);
} else if (strncmp(feature, PROFILER_INTERVAL, bufferSize) == 0) {
set_profiler_interval(value);
} else if (strncmp(feature, PROFILER_ENTRIES, bufferSize) == 0) {
set_profiler_entries(value);
} else if (strncmp(feature, PROFILER_STACK, bufferSize) == 0) {
set_profiler_scan(value);
} else if (strncmp(feature, PROFILER_FEATURES, bufferSize) == 0) {
*featureCount = readCSVArray(value, features);
} else if (strncmp(feature, "threads", bufferSize) == 0) {
*threadCount = readCSVArray(value, threadNames);
}
}
fclose(file);
}
}
static void StartSignalHandler(int signal, siginfo_t* info, void* context) {
// XXX: Everything we do here is NOT async signal safe. We risk nasty things
// like deadlocks but we typically only do this once so it tends to be ok.
// See bug 909403
uint32_t featureCount = 0;
uint32_t threadCount = 0;
// Just allocate 10 features for now
// FIXME: these don't really point to const chars*
// So we free them later, but we don't want to change the const char**
// declaration in profiler_start. Annoying but ok for now.
const char* threadNames[10];
const char* features[10];
const char* profilerConfigFile = "/data/local/tmp/profiler.options";
ReadProfilerVars(profilerConfigFile, features, &featureCount, threadNames, &threadCount);
MOZ_ASSERT(featureCount < 10);
MOZ_ASSERT(threadCount < 10);
profiler_start(PROFILE_DEFAULT_ENTRY, 1,
features, featureCount,
threadNames, threadCount);
freeArray(threadNames, threadCount);
freeArray(features, featureCount);
}
void OS::Startup()
{
LOG("Registering start signal");
struct sigaction sa;
sa.sa_sigaction = StartSignalHandler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART | SA_SIGINFO;
if (sigaction(SIGSTART, &sa, &old_sigstart_signal_handler) != 0) {
LOG("Error installing signal");
}
}
#else
void OS::Startup() {
// Set up the fork handlers.
setup_atfork();
}
#endif
void TickSample::PopulateContext(void* aContext)
{
MOZ_ASSERT(aContext);
ucontext_t* pContext = reinterpret_cast<ucontext_t*>(aContext);
if (!getcontext(pContext)) {
context = pContext;
SetSampleContext(this, aContext);
}
}
void OS::SleepMicro(int microseconds)
{
if (MOZ_UNLIKELY(microseconds >= 1000000)) {
// Use usleep for larger intervals, because the nanosleep
// code below only supports intervals < 1 second.
MOZ_ALWAYS_TRUE(!::usleep(microseconds));
return;
}
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = microseconds * 1000UL;
int rv = ::nanosleep(&ts, &ts);
while (rv != 0 && errno == EINTR) {
// Keep waiting in case of interrupt.
// nanosleep puts the remaining time back into ts.
rv = ::nanosleep(&ts, &ts);
}
MOZ_ASSERT(!rv, "nanosleep call failed");
}