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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#include "mozilla/ProfilerThreadRegistration.h"
#include "mozilla/ProfilerMarkers.h"
#include "mozilla/ProfilerThreadRegistry.h"
#include "nsString.h"
#ifdef MOZ_GECKO_PROFILER
# include "platform.h"
#else
# define profiler_mark_thread_awake()
# define profiler_mark_thread_asleep()
#endif
namespace mozilla::profiler {
/* static */
MOZ_THREAD_LOCAL(ThreadRegistration*) ThreadRegistration::tlsThreadRegistration;
ThreadRegistration::ThreadRegistration(const char* aName, const void* aStackTop)
: mData(aName, aStackTop) {
auto* tls = GetTLS();
if (MOZ_UNLIKELY(!tls)) {
// No TLS, nothing can be done without it.
return;
}
if (ThreadRegistration* rootRegistration = tls->get(); rootRegistration) {
// This is a nested ThreadRegistration object, so the thread is already
// registered in the TLS and ThreadRegistry and we don't need to register
// again.
MOZ_ASSERT(
mData.Info().ThreadId() == rootRegistration->mData.Info().ThreadId(),
"Thread being re-registered has changed its TID");
// TODO: Use new name. This is currently not possible because the
// TLS-stored RegisteredThread's ThreadInfo cannot be changed.
// In the meantime, we record a marker that could be used in the frontend.
PROFILER_MARKER_TEXT("Nested ThreadRegistration()", OTHER_Profiling,
MarkerOptions{},
ProfilerString8View::WrapNullTerminatedString(aName));
return;
}
tls->set(this);
ThreadRegistry::Register(OnThreadRef{*this});
profiler_mark_thread_awake();
}
ThreadRegistration::~ThreadRegistration() {
MOZ_ASSERT(profiler_current_thread_id() == mData.mInfo.ThreadId(),
"ThreadRegistration must be destroyed on its thread");
MOZ_ASSERT(!mDataMutex.IsLockedOnCurrentThread(),
"Mutex shouldn't be locked here, as it's about to be destroyed "
"in ~ThreadRegistration()");
auto* tls = GetTLS();
if (MOZ_UNLIKELY(!tls)) {
// No TLS, nothing can be done without it.
return;
}
if (ThreadRegistration* rootRegistration = tls->get(); rootRegistration) {
if (rootRegistration != this) {
// `this` is not in the TLS, so it was a nested registration, there is
// nothing to unregister yet.
PROFILER_MARKER_TEXT(
"Nested ~ThreadRegistration()", OTHER_Profiling, MarkerOptions{},
ProfilerString8View::WrapNullTerminatedString(mData.Info().Name()));
return;
}
profiler_mark_thread_asleep();
#ifdef NIGHTLY_BUILD
mData.RecordWakeCount();
#endif
ThreadRegistry::Unregister(OnThreadRef{*this});
#ifdef DEBUG
// After ThreadRegistry::Unregister, other threads should not be able to
// find this ThreadRegistration, and shouldn't have kept any reference to
// it across the ThreadRegistry mutex.
MOZ_ASSERT(mDataMutex.TryLock(),
"Mutex shouldn't be locked in any thread, as it's about to be "
"destroyed in ~ThreadRegistration()");
// Undo the above successful TryLock.
mDataMutex.Unlock();
#endif // DEBUG
tls->set(nullptr);
return;
}
// Already removed from the TLS!? This could happen with improperly-nested
// register/unregister calls, and the first ThreadRegistration has already
// been unregistered.
// We cannot record a marker on this thread because it was already
// unregistered. Send it to the main thread (unless this *is* already the
// main thread, which has been unregistered); this may be useful to catch
// mismatched register/unregister pairs in Firefox.
if (!profiler_is_main_thread()) {
nsAutoCString threadId("thread id: ");
threadId.AppendInt(profiler_current_thread_id().ToNumber());
threadId.AppendLiteral(", name: \"");
threadId.AppendASCII(mData.Info().Name());
threadId.AppendLiteral("\"");
PROFILER_MARKER_TEXT(
"~ThreadRegistration() but TLS is empty", OTHER_Profiling,
MarkerOptions(MarkerThreadId::MainThread(), MarkerStack::Capture()),
threadId);
}
}
/* static */
ProfilingStack* ThreadRegistration::RegisterThread(const char* aName,
const void* aStackTop) {
auto* tls = GetTLS();
if (MOZ_UNLIKELY(!tls)) {
// No TLS, nothing can be done without it.
return nullptr;
}
if (ThreadRegistration* rootRegistration = tls->get(); rootRegistration) {
// Already registered, record the extra depth to ignore the matching
// UnregisterThread.
++rootRegistration->mOtherRegistrations;
// TODO: Use new name. This is currently not possible because the
// TLS-stored RegisteredThread's ThreadInfo cannot be changed.
// In the meantime, we record a marker that could be used in the frontend.
PROFILER_MARKER_TEXT("Nested ThreadRegistration::RegisterThread()",
OTHER_Profiling, MarkerOptions{},
ProfilerString8View::WrapNullTerminatedString(aName));
return &rootRegistration->mData.mProfilingStack;
}
// Create on heap, it self-registers with the TLS (its effective owner, so
// we can forget the pointer after this), and with the Profiler.
ThreadRegistration* tr = new ThreadRegistration(aName, aStackTop);
tr->mIsOnHeap = true;
return &tr->mData.mProfilingStack;
}
/* static */
void ThreadRegistration::UnregisterThread() {
auto* tls = GetTLS();
if (MOZ_UNLIKELY(!tls)) {
// No TLS, nothing can be done without it.
return;
}
if (ThreadRegistration* rootRegistration = tls->get(); rootRegistration) {
if (rootRegistration->mOtherRegistrations != 0) {
// This is assumed to be a matching UnregisterThread() for a nested
// RegisterThread(). Decrease depth and we're done.
--rootRegistration->mOtherRegistrations;
// We don't know what name was used in the related RegisterThread().
PROFILER_MARKER_UNTYPED("Nested ThreadRegistration::UnregisterThread()",
OTHER_Profiling);
return;
}
if (!rootRegistration->mIsOnHeap) {
// The root registration was not added by `RegisterThread()`, so it
// shouldn't be deleted!
// This could happen if there are un-paired `UnregisterThread` calls when
// the initial registration (still alive) was done on the stack. We don't
// know what name was used in the related RegisterThread().
PROFILER_MARKER_UNTYPED("Excess ThreadRegistration::UnregisterThread()",
OTHER_Profiling, MarkerStack::Capture());
return;
}
// This is the last `UnregisterThread()` that should match the first
// `RegisterThread()` that created this ThreadRegistration on the heap.
// Just delete this root registration, it will de-register itself from the
// TLS (and from the Profiler).
delete rootRegistration;
return;
}
// There is no known ThreadRegistration for this thread, ignore this
// request. We cannot record a marker on this thread because it was already
// unregistered. Send it to the main thread (unless this *is* already the
// main thread, which has been unregistered); this may be useful to catch
// mismatched register/unregister pairs in Firefox.
if (!profiler_is_main_thread()) {
nsAutoCString threadId("thread id: ");
threadId.AppendInt(profiler_current_thread_id().ToNumber());
PROFILER_MARKER_TEXT(
"ThreadRegistration::UnregisterThread() but TLS is empty",
OTHER_Profiling,
MarkerOptions(MarkerThreadId::MainThread(), MarkerStack::Capture()),
threadId);
}
}
} // namespace mozilla::profiler
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