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// -*- mode: C++; c-file-style: "cc-mode" -*-
//=============================================================================
//
// Code available from: https://verilator.org
//
// Copyright 2012-2025 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.
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
//
//=============================================================================
///
/// \file
/// \brief Verilated run-time profiling implementation code
///
//=============================================================================
#include "verilatedos.h"
#include "verilated_profiler.h"
#include "verilated_threads.h"
#include <fstream>
#include <string>
//=============================================================================
// Globals
// Internal note: Globals may multi-construct, see verilated.cpp top.
thread_local VlExecutionProfiler::ExecutionTrace VlExecutionProfiler::t_trace;
constexpr const char* const VlExecutionRecord::s_ascii[];
//=============================================================================
// VlExecutionProfiler implementation
template <size_t N>
static size_t roundUptoMultipleOf(size_t value) {
static_assert((N & (N - 1)) == 0, "'N' must be a power of 2");
size_t mask = N - 1;
return (value + mask) & ~mask;
}
VlExecutionProfiler::VlExecutionProfiler(VerilatedContext& context)
: m_context{context} {
// Setup profiling on main thread
setupThread(0);
}
void VlExecutionProfiler::configure() {
if (VL_UNLIKELY(m_enabled)) {
--m_windowCount;
if (VL_UNLIKELY(m_windowCount == m_context.profExecWindow())) {
VL_DEBUG_IF(VL_DBG_MSGF("+ profile start collection\n"););
clear(); // Clear the profile after the cache warm-up cycles.
m_tickBegin = VL_CPU_TICK();
} else if (VL_UNLIKELY(m_windowCount == 0)) {
const uint64_t tickEnd = VL_CPU_TICK();
VL_DEBUG_IF(VL_DBG_MSGF("+ profile end\n"););
const std::string& fileName = m_context.profExecFilename();
dump(fileName.c_str(), tickEnd);
m_enabled = false;
}
return;
}
const uint64_t startReq = m_context.profExecStart() + 1; // + 1, so we can start at time 0
if (VL_UNLIKELY(m_lastStartReq < startReq && VL_TIME_Q() >= m_context.profExecStart())) {
VL_DEBUG_IF(VL_DBG_MSGF("+ profile start warmup\n"););
VL_DEBUG_IF(assert(m_windowCount == 0););
m_enabled = true;
m_windowCount = m_context.profExecWindow() * 2;
m_lastStartReq = startReq;
}
}
VerilatedVirtualBase* VlExecutionProfiler::construct(VerilatedContext& context) {
VlExecutionProfiler* const selfp = new VlExecutionProfiler{context};
if (VlThreadPool* const threadPoolp = static_cast<VlThreadPool*>(context.threadPoolp())) {
for (int i = 0; i < threadPoolp->numThreads(); ++i) {
// Data to pass to worker thread initialization
struct Data final {
VlExecutionProfiler* const selfp;
const uint32_t threadId;
} data{selfp, static_cast<uint32_t>(i + 1)};
// Initialize worker thread
threadPoolp->workerp(i)->addTask(
[](void* userp, bool) {
Data* const datap = static_cast<Data*>(userp);
datap->selfp->setupThread(datap->threadId);
},
&data);
// Wait until initialization is complete
threadPoolp->workerp(i)->wait();
}
}
return selfp;
}
void VlExecutionProfiler::setupThread(uint32_t threadId) {
// Reserve some space in the thread-local profiling buffer, in order to try to avoid malloc
// while profiling.
t_trace.reserve(RESERVED_TRACE_CAPACITY);
// Register thread-local buffer in list of all buffers
bool exists;
{
const VerilatedLockGuard lock{m_mutex};
exists = !m_traceps.emplace(threadId, &t_trace).second;
}
if (VL_UNLIKELY(exists)) {
VL_FATAL_MT(__FILE__, __LINE__, "", "multiple initialization of profiler on some thread");
}
}
void VlExecutionProfiler::clear() VL_MT_SAFE_EXCLUDES(m_mutex) {
const VerilatedLockGuard lock{m_mutex};
for (const auto& pair : m_traceps) {
ExecutionTrace* const tracep = pair.second;
const size_t reserve = roundUptoMultipleOf<RESERVED_TRACE_CAPACITY>(tracep->size());
tracep->clear();
tracep->reserve(reserve);
}
}
void VlExecutionProfiler::dump(const char* filenamep, uint64_t tickEnd)
VL_MT_SAFE_EXCLUDES(m_mutex) {
const VerilatedLockGuard lock{m_mutex};
VL_DEBUG_IF(VL_DBG_MSGF("+prof+exec writing to '%s'\n", filenamep););
FILE* const fp = std::fopen(filenamep, "w");
if (VL_UNLIKELY(!fp)) VL_FATAL_MT(filenamep, 0, "", "+prof+exec+file file not writable");
// TODO Perhaps merge with verilated_coverage output format, so can
// have a common merging and reporting tool, etc.
fprintf(fp, "VLPROFVERSION 2.2 # Verilator execution profile version 2.2\n");
fprintf(fp, "VLPROF arg +verilator+prof+exec+start+%" PRIu64 "\n",
Verilated::threadContextp()->profExecStart());
fprintf(fp, "VLPROF arg +verilator+prof+exec+window+%u\n",
Verilated::threadContextp()->profExecWindow());
std::string numa = "no threads";
if (VlThreadPool* const threadPoolp
= static_cast<VlThreadPool*>(Verilated::threadContextp()->threadPoolp())) {
numa = threadPoolp->numaStatus();
}
fprintf(fp, "VLPROF info numa %s\n", numa.c_str());
// Note that VerilatedContext will by default create as many threads as there are hardware
// processors, but not all of them might be utilized. Report the actual number that has trace
// entries to avoid over-counting.
unsigned threads = 0;
for (const auto& pair : m_traceps) {
if (!pair.second->empty()) ++threads;
}
fprintf(fp, "VLPROF stat threads %u\n", threads);
fprintf(fp, "VLPROF stat yields %" PRIu64 "\n", VlMTaskVertex::yields());
// Copy /proc/cpuinfo into this output so verilator_gantt can be run on
// a different machine
{
const std::unique_ptr<std::ifstream> ifp{new std::ifstream{"/proc/cpuinfo"}};
if (!ifp->fail()) {
std::string line;
while (std::getline(*ifp, line)) { fprintf(fp, "VLPROFPROC %s\n", line.c_str()); }
}
}
for (const auto& pair : m_traceps) {
const uint32_t threadId = pair.first;
ExecutionTrace* const tracep = pair.second;
if (tracep->empty()) continue;
fprintf(fp, "VLPROFTHREAD %" PRIu32 "\n", threadId);
for (const VlExecutionRecord& er : *tracep) {
const char* const name = VlExecutionRecord::s_ascii[static_cast<uint8_t>(er.m_type)];
const uint64_t time = er.m_tick - m_tickBegin;
fprintf(fp, "VLPROFEXEC %s %" PRIu64, name, time);
switch (er.m_type) {
case VlExecutionRecord::Type::SECTION_POP:
case VlExecutionRecord::Type::EXEC_GRAPH_BEGIN:
case VlExecutionRecord::Type::EXEC_GRAPH_END:
// No payload
fprintf(fp, "\n");
break;
case VlExecutionRecord::Type::MTASK_BEGIN: {
const auto& payload = er.m_payload.mtaskBegin;
if (payload.m_hierBlock[0] != '\0') {
fprintf(fp, " id %u predictStart %u cpu %u hierBlock %s\n", payload.m_id,
payload.m_predictStart, payload.m_cpu, payload.m_hierBlock);
} else {
fprintf(fp, " id %u predictStart %u cpu %u\n", payload.m_id,
payload.m_predictStart, payload.m_cpu);
}
break;
}
case VlExecutionRecord::Type::MTASK_END: {
const auto& payload = er.m_payload.mtaskEnd;
fprintf(fp, " predictCost %u\n", payload.m_predictCost);
break;
}
case VlExecutionRecord::Type::THREAD_SCHEDULE_WAIT_BEGIN:
case VlExecutionRecord::Type::THREAD_SCHEDULE_WAIT_END: {
const auto& payload = er.m_payload.threadScheduleWait;
fprintf(fp, " cpu %u\n", payload.m_cpu);
break;
}
case VlExecutionRecord::Type::SECTION_PUSH: {
const auto& payload = er.m_payload.sectionPush;
fprintf(fp, " %s\n", payload.m_name);
break;
}
default: abort(); // LCOV_EXCL_LINE
}
}
}
fprintf(fp, "VLPROF stat ticks %" PRIu64 "\n", tickEnd - m_tickBegin);
std::fclose(fp);
}
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