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c267d99198
Implement a ring buffer that is not thread-safe and preallocate its internal buffers. The intention is that the internal data is preallocate to any thread and then read/write operations will take place in a single thread using the memory in a ring manner. Differential Revision: https://phabricator.services.mozilla.com/D74882
78 lines
2.3 KiB
C++
78 lines
2.3 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include <csignal>
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#include <cerrno>
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#include <pthread.h>
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#include <mozilla/Sprintf.h>
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#include <mozilla/Atomics.h>
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#include "audio_thread_priority.h"
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#include "nsDebug.h"
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namespace mozilla {
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Atomic<bool, MemoryOrdering::ReleaseAcquire> gRealtimeLimitReached;
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void UnderrunHandler(int signum) { gRealtimeLimitReached = true; }
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bool SoftRealTimeLimitReached() { return gRealtimeLimitReached; }
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void InstallSoftRealTimeLimitHandler() {
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struct sigaction action, previous;
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action.sa_handler = UnderrunHandler;
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sigemptyset(&action.sa_mask);
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action.sa_flags = 0;
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int rv = sigaction(SIGXCPU, &action, &previous);
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if (rv != 0) {
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char buf[256];
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SprintfLiteral(buf, "sigaction(SIGXCPU, ...): %s", strerror(errno));
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NS_WARNING(buf);
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return;
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}
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void* previous_handler = previous.sa_flags == SA_SIGINFO
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? reinterpret_cast<void*>(previous.sa_sigaction)
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: reinterpret_cast<void*>(previous.sa_handler);
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MOZ_ASSERT(previous_handler != UnderrunHandler,
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"Only install the SIGXCPU handler once per process.");
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if (previous_handler != SIG_DFL && previous_handler != UnderrunHandler) {
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NS_WARNING(
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"SIGXCPU handler was already set by something else, dropping real-time "
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"priority.");
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rv = sigaction(SIGXCPU, &previous, nullptr);
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if (rv != 0) {
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NS_WARNING("Could not restore previous handler for SIGXCPU.");
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}
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gRealtimeLimitReached = true;
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return;
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}
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gRealtimeLimitReached = false;
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}
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void DemoteThreadFromRealTime() {
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atp_thread_info* info = atp_get_current_thread_info();
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if (!info) {
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NS_WARNING("Could not get current thread info when demoting thread.");
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return;
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}
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int rv = atp_demote_thread_from_real_time(info);
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if (rv) {
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NS_WARNING("Could not demote thread from real-time.");
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return;
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}
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rv = atp_free_thread_info(info);
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if (rv) {
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NS_WARNING("Could not free atp_thread_info struct");
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}
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gRealtimeLimitReached = false;
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}
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} // namespace mozilla
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