MAJOR: Add multithreaded model generation.

include/verilated_threads.cpp

@@ -0,0 +1,229 @@
+// -*- mode: C++; c-file-style: "cc-mode" -*-
+//=============================================================================
+//
+// THIS MODULE IS PUBLICLY LICENSED
+//
+// Copyright 2012-2018 by Wilson Snyder.  This program is free software;
+// you can redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License Version 2.0.
+//
+// This is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+//
+//=============================================================================
+///
+/// \file
+/// \brief Thread pool for verilated modules
+///
+//=============================================================================
+
+#include "verilatedos.h"
+#include "verilated_threads.h"
+#include <cstdio>
+
+std::atomic<vluint64_t> VlNotification::s_yields;
+
+VL_THREAD_LOCAL VlThreadPool::ProfileTrace* VlThreadPool::t_profilep = NULL;
+
+//=============================================================================
+// VlMTaskVertex
+
+VlMTaskVertex::VlMTaskVertex(vluint32_t upstreamDepCount)
+    : m_upstreamDepsDone(0),
+      m_upstreamDepCount(upstreamDepCount) {
+    assert(atomic_is_lock_free(&m_upstreamDepsDone));
+}
+
+//=============================================================================
+// VlWorkerThread
+
+VlWorkerThread::VlWorkerThread(VlThreadPool* poolp, bool profiling)
+    : m_poolp(poolp)
+    , m_profiling(profiling)
+    , m_exiting(false)
+      // Must init this last -- after setting up fields that it might read:
+    , m_cthread(startWorker, this) {}
+
+VlWorkerThread::~VlWorkerThread() {
+    m_exiting.store(true, std::memory_order_release);
+    {
+        VerilatedLockGuard lk(m_mutex);
+        if (sleeping()) {
+            wakeUp();
+        }
+    }
+    // The thread should exit; join it.
+    m_cthread.join();
+}
+
+void VlWorkerThread::workerLoop() {
+    if (VL_UNLIKELY(m_profiling)) {
+        m_poolp->setupProfilingClientThread();
+    }
+
+    VlNotification alarm;
+    ExecRec work;
+    work.m_fnp = NULL;
+
+    while (1) {
+        bool sleep = false;
+        if (VL_UNLIKELY(!work.m_fnp)) {
+            // Look for work
+            VerilatedLockGuard lk(m_mutex);
+            if (VL_LIKELY(!m_ready.empty())) {
+                dequeWork(&work);
+            } else {
+                // No work available, prepare to sleep. Pass alarm/work
+                // into m_sleepAlarm so wakeUp will tall this function.
+                //
+                // Must modify m_sleepAlarm in the same critical section as
+                // the check for ready work, otherwise we could race with
+                // another thread enqueueing work and never be awoken.
+                m_sleepAlarm.first = &alarm;
+                m_sleepAlarm.second = &work;
+                sleep = true;
+            }
+        }
+
+        // Do this here, not above, to avoid a race with the destructor.
+        if (VL_UNLIKELY(m_exiting.load(std::memory_order_acquire)))
+            break;
+
+        if (VL_UNLIKELY(sleep)) {
+            alarm.waitForNotification();  // ZZZzzzzz
+            alarm.reset();
+        }
+        if (VL_LIKELY(work.m_fnp)) {
+            work.m_fnp(work.m_evenCycle, work.m_sym);
+            work.m_fnp = NULL;
+        }
+    }
+
+    if (VL_UNLIKELY(m_profiling)) {
+        m_poolp->tearDownProfilingClientThread();
+    }
+}
+
+void VlWorkerThread::startWorker(VlWorkerThread* workerp) {
+    workerp->workerLoop();
+}
+
+//=============================================================================
+// VlThreadPool
+
+VlThreadPool::VlThreadPool(int nThreads, bool profiling)
+    : m_profiling(profiling) {
+    // --threads N passes nThreads=N-1, as the "main" threads counts as 1
+    unsigned cpus = std::thread::hardware_concurrency();
+    if (cpus < nThreads+1) {
+        VL_PRINTF_MT("%%Warning: System has %u CPUs but model Verilated with"
+                     " --threads %d; may run slow.\n", cpus, nThreads+1);
+    }
+    // Create'em
+    for (int i=0; i<nThreads; ++i) {
+        m_workers.push_back(new VlWorkerThread(this, profiling));
+    }
+    // Set up a profile buffer for the current thread too -- on the
+    // assumption that it's the same thread that calls eval and may be
+    // donated to run mtasks during the eval.
+    if (VL_UNLIKELY(m_profiling)) {
+        setupProfilingClientThread();
+    }
+}
+
+VlThreadPool::~VlThreadPool() {
+    for (int i = 0; i < m_workers.size(); ++i) {
+        // Each ~WorkerThread will wait for its thread to exit.
+        delete m_workers[i];
+    }
+    if (VL_UNLIKELY(m_profiling)) {
+        tearDownProfilingClientThread();
+    }
+}
+
+void VlThreadPool::tearDownProfilingClientThread() {
+    assert(t_profilep);
+    delete t_profilep;
+    t_profilep = NULL;
+}
+
+void VlThreadPool::setupProfilingClientThread() {
+    assert(!t_profilep);
+    t_profilep = new ProfileTrace;
+    // Reserve some space in the thread-local profiling buffer;
+    // try not to malloc while collecting profiling.
+    t_profilep->reserve(4096);
+    {
+        VerilatedLockGuard lk(m_mutex);
+        m_allProfiles.insert(t_profilep);
+    }
+}
+
+void VlThreadPool::profileAppendAll(const VlProfileRec& rec) {
+    VerilatedLockGuard lk(m_mutex);
+    for (ProfileSet::iterator it = m_allProfiles.begin();
+         it != m_allProfiles.end(); ++it) {
+        // Every thread's profile trace gets a copy of rec.
+        (*it)->emplace_back(rec);
+    }
+}
+
+void VlThreadPool::profileDump(const char* filenamep, vluint64_t ticksElapsed) {
+    VerilatedLockGuard lk(m_mutex);
+    VL_DEBUG_IF(VL_DBG_MSGF("+prof+threads writing to '%s'\n", filenamep););
+
+    FILE* fp = fopen(filenamep, "w");
+    if (VL_UNLIKELY(!fp)) {
+        VL_FATAL_MT(filenamep, 0, "", "+prof+threads+file file not writable");
+        return;
+    }
+
+    // TODO Perhaps merge with verilated_coverage output format, so can
+    // have a common merging and reporting tool, etc.
+    fprintf(fp, "VLPROFTHREAD 1.0 # Verilator thread profile dump version 1.0\n");
+    fprintf(fp, "VLPROF arg --threads %" VL_PRI64 "u\n",
+            vluint64_t(m_workers.size()+1));
+    fprintf(fp, "VLPROF arg +verilator+prof+threads+start+%" VL_PRI64 "u\n",
+            Verilated::profThreadsStart());
+    fprintf(fp, "VLPROF arg +verilator+prof+threads+window+%u\n",
+            Verilated::profThreadsWindow());
+    fprintf(fp, "VLPROF stat yields %" VL_PRI64 "u\n",
+            VlNotification::yields());
+
+    vluint32_t thread_id = 0;
+    for (ProfileSet::iterator pit = m_allProfiles.begin();
+         pit != m_allProfiles.end(); ++pit) {
+        ++thread_id;
+
+        bool printing = false;  // False while in warmup phase
+        for (ProfileTrace::iterator eit = (*pit)->begin();
+             eit != (*pit)->end(); ++eit) {
+            switch (eit->m_type) {
+            case VlProfileRec::TYPE_BARRIER:
+                printing = true;
+                break;
+            case VlProfileRec::TYPE_MTASK_RUN:
+                if (!printing) break;
+                fprintf(fp, "VLPROF mtask %d"
+                        " start %" VL_PRI64"u end %" VL_PRI64"u elapsed %" VL_PRI64 "u"
+                        " predict_time %u cpu %u on thread %u\n",
+                        eit->m_mtaskId,
+                        eit->m_startTime,
+                        eit->m_endTime,
+                        (eit->m_endTime - eit->m_startTime),
+                        eit->m_predictTime,
+                        eit->m_cpu,
+                        thread_id);
+                break;
+            default: assert(false);
+                break;
+            }
+        }
+    }
+    fprintf(fp, "VLPROF stat ticks %" VL_PRI64 "u\n",
+            ticksElapsed);
+
+    fclose(fp);
+}