diff options
Diffstat (limited to 'tools/profiler/core/platform-linux.cc')
| -rw-r--r-- | tools/profiler/core/platform-linux.cc | 715 |
1 files changed, 715 insertions, 0 deletions
diff --git a/tools/profiler/core/platform-linux.cc b/tools/profiler/core/platform-linux.cc new file mode 100644 index 0000000000..160873c9dc --- /dev/null +++ b/tools/profiler/core/platform-linux.cc @@ -0,0 +1,715 @@ +// 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 "prenv.h" +#include "platform.h" +#include "GeckoProfiler.h" +#include "mozilla/Mutex.h" +#include "mozilla/Atomics.h" +#include "mozilla/LinuxSignal.h" +#include "mozilla/TimeStamp.h" +#include "mozilla/DebugOnly.h" +#include "ProfileEntry.h" +#include "nsThreadUtils.h" +#include "GeckoSampler.h" +#include "ThreadResponsiveness.h" + +#if defined(__ARM_EABI__) && defined(ANDROID) + // Should also work on other Android and ARM Linux, but not tested there yet. +# define USE_EHABI_STACKWALK +# include "EHABIStackWalk.h" +#elif defined(SPS_PLAT_amd64_linux) || defined(SPS_PLAT_x86_linux) +# define USE_LUL_STACKWALK +# include "lul/LulMain.h" +# include "lul/platform-linux-lul.h" +#endif + +// Memory profile +#include "nsMemoryReporterManager.h" + +#include <string.h> +#include <list> + +#define SIGNAL_SAVE_PROFILE SIGUSR2 + +using namespace mozilla; + +#if defined(USE_LUL_STACKWALK) +// A singleton instance of the library. It is initialised at first +// use. Currently only the main thread can call Sampler::Start, so +// there is no need for a mechanism to ensure that it is only +// created once in a multi-thread-use situation. +lul::LUL* sLUL = nullptr; + +// This is the sLUL initialization routine. +static void sLUL_initialization_routine(void) +{ + MOZ_ASSERT(!sLUL); + MOZ_ASSERT(gettid() == getpid()); /* "this is the main thread" */ + sLUL = new lul::LUL(logging_sink_for_LUL); + // Read all the unwind info currently available. + read_procmaps(sLUL); +} +#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) { + // Avoid TSan warning about clobbering errno. + int savedErrno = errno; + + if (!Sampler::GetActiveSampler()) { + sem_post(&sSignalHandlingDone); + errno = savedErrno; + 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); + errno = savedErrno; +} + +} // 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; + } +} + +int tgkill(pid_t tgid, pid_t tid, int signalno) { + return syscall(SYS_tgkill, tgid, tid, signalno); +} + +class PlatformData { + public: + PlatformData() + { + MOZ_COUNT_CTOR(PlatformData); + } + + ~PlatformData() + { + MOZ_COUNT_DTOR(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); + + int vm_tgid_ = getpid(); + DebugOnly<int> my_tid = gettid(); + + unsigned int nSignalsSent = 0; + + TimeDuration lastSleepOverhead = 0; + TimeStamp sampleStart = TimeStamp::Now(); + while (SamplerRegistry::sampler->IsActive()) { + + SamplerRegistry::sampler->HandleSaveRequest(); + SamplerRegistry::sampler->DeleteExpiredMarkers(); + + if (!SamplerRegistry::sampler->IsPaused()) { + ::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() || info->IsPendingDelete()) + continue; + + PseudoStack::SleepState sleeping = info->Stack()->observeSleeping(); + if (sleeping == PseudoStack::SLEEPING_AGAIN) { + info->Profile()->DuplicateLastSample(); + 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(); + MOZ_ASSERT(threadId != my_tid); + + // 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(); +#else + continue; +#endif + } + + // Wait for the signal handler to run before moving on to the next one + sem_wait(&sSignalHandlingDone); + isFirstProfiledThread = false; + + // The LUL unwind object accumulates frame statistics. + // Periodically we should poke it to give it a chance to print + // those statistics. This involves doing I/O (fprintf, + // __android_log_print, etc) and so can't safely be done from + // the unwinder threads, which is why it is done here. + if ((++nSignalsSent & 0xF) == 0) { +# if defined(USE_LUL_STACKWALK) + sLUL->MaybeShowStats(); +# endif + } + } + } + + TimeStamp targetSleepEndTime = sampleStart + TimeDuration::FromMicroseconds(SamplerRegistry::sampler->interval() * 1000); + TimeStamp beforeSleep = TimeStamp::Now(); + TimeDuration targetSleepDuration = targetSleepEndTime - beforeSleep; + double sleepTime = std::max(0.0, (targetSleepDuration - lastSleepOverhead).ToMicroseconds()); + OS::SleepMicro(sleepTime); + sampleStart = TimeStamp::Now(); + lastSleepOverhead = sampleStart - (beforeSleep + TimeDuration::FromMicroseconds(sleepTime)); + } + return 0; +} + +Sampler::Sampler(double interval, bool profiling, int entrySize) + : interval_(interval), + profiling_(profiling), + paused_(false), + active_(false), + entrySize_(entrySize) { + MOZ_COUNT_CTOR(Sampler); +} + +Sampler::~Sampler() { + MOZ_COUNT_DTOR(Sampler); + ASSERT(!signal_sender_launched_); +} + + +void Sampler::Start() { + LOG("Sampler started"); + +#if defined(USE_EHABI_STACKWALK) + mozilla::EHABIStackWalkInit(); +#elif defined(USE_LUL_STACKWALK) + // NOTE: this isn't thread-safe. But we expect Sampler::Start to be + // called only from the main thread, so this is OK in general. + if (!sLUL) { + sLUL_initialization_routine(); + } +#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; + +#if defined(USE_LUL_STACKWALK) + // Switch into unwind mode. After this point, we can't add or + // remove any unwind info to/from this LUL instance. The only thing + // we can do with it is Unwind() calls. + sLUL->EnableUnwinding(); + + // Has a test been requested? + if (PR_GetEnv("MOZ_PROFILER_LUL_TEST")) { + int nTests = 0, nTestsPassed = 0; + RunLulUnitTests(&nTests, &nTestsPassed, sLUL); + } +#endif + + // 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; + + ::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 && !info->IsPendingDelete()) { + // Thread already registered. This means the first unregister will be + // too early. + ASSERT(false); + return false; + } + } + + set_tls_stack_top(stackTop); + + ThreadInfo* info = new StackOwningThreadInfo(aName, id, + aIsMainThread, aPseudoStack, stackTop); + + if (sActiveSampler) { + sActiveSampler->RegisterThread(info); + } + + sRegisteredThreads->push_back(info); + + return true; +} + +void Sampler::UnregisterCurrentThread() +{ + if (!Sampler::sRegisteredThreadsMutex) + return; + + tlsStackTop.set(nullptr); + + ::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 && !info->IsPendingDelete()) { + if (profiler_is_active()) { + // We still want to show the results of this thread if you + // save the profile shortly after a thread is terminated. + // For now we will defer the delete to profile stop. + info->SetPendingDelete(); + break; + } else { + delete info; + sRegisteredThreads->erase(sRegisteredThreads->begin() + i); + break; + } + } + } +} + +#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_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 DoStartTask() { + 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); +} + +static void StartSignalHandler(int signal, siginfo_t* info, void* context) { + class StartTask : public Runnable { + public: + NS_IMETHOD Run() override { + DoStartTask(); + return NS_OK; + } + }; + // XXX: technically NS_DispatchToMainThread is NOT async signal safe. We risk + // nasty things like deadlocks, but the probability is very low and we + // typically only do this once so it tends to be ok. See bug 909403. + NS_DispatchToMainThread(new StartTask()); +} + +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"); +} |