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#include "perfetto-tracing.h"
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#ifdef WORKERD_USE_PERFETTO
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#include "protos/perfetto/config/data_source_config.gen.h"
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#include "protos/perfetto/config/trace_config.gen.h"
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#include "protos/perfetto/config/track_event/track_event_config.gen.h"
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#include <fcntl.h>
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#include <perfetto/tracing/track_event_legacy.h>
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#include <kj/debug.h>
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#include <kj/filesystem.h>
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#include <kj/memory.h>
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#include <kj/vector.h>
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PERFETTO_TRACK_EVENT_STATIC_STORAGE_IN_NAMESPACE(workerd::traces);
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namespace workerd {
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namespace {
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kj::OwnFd openTraceFile(kj::StringPtr path) {
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  int fd = open(path.cStr(), O_RDWR | O_CREAT | O_TRUNC, 0600);
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  KJ_REQUIRE(fd >= 0, "Unable to open tracing file");
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  return kj::OwnFd(fd);
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}
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void initializePerfettoOnce() {
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  if (perfetto::Tracing::IsInitialized()) return;
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  perfetto::TracingInitArgs args;
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  args.backends |= perfetto::kInProcessBackend;
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  perfetto::Tracing::Initialize(args);
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  PerfettoSession::registerWorkerdTracks();
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}
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std::unique_ptr<perfetto::TracingSession> createTracingSession(int fd, kj::StringPtr categories) {
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  initializePerfettoOnce();
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  perfetto::protos::gen::TrackEventConfig track_event_cfg;
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  track_event_cfg.add_disabled_categories("*");
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  // The categories is a comma-separated list
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  auto cats = PerfettoSession::parseCategories(categories);
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  for (auto category: cats) {
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    auto view = std::string(category.begin(), category.size());
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    track_event_cfg.add_enabled_categories(view);
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  }
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  perfetto::TraceConfig cfg;
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  cfg.add_buffers()->set_size_kb(1024);  // Record up to 1 MiB.
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  auto* ds_cfg = cfg.add_data_sources()->mutable_config();
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  ds_cfg->set_name("track_event");
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  ds_cfg->set_track_event_config_raw(track_event_cfg.SerializeAsString());
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  std::unique_ptr<perfetto::TracingSession> tracing_session(perfetto::Tracing::NewTrace());
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  tracing_session->Setup(cfg, fd);
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  return kj::mv(tracing_session);
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}
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}  // namespace
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void PerfettoSession::registerWorkerdTracks() {
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  static bool once = true;
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  KJ_ASSERT(once, "workerd perfetto tracks are already registered");
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  if (perfetto::Tracing::IsInitialized()) {
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    workerd::traces::TrackEvent::Register();
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    once = false;
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  }
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}
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kj::Array<kj::ArrayPtr<const char>> PerfettoSession::parseCategories(kj::StringPtr categories) {
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  kj::Vector<kj::ArrayPtr<const char>> results;
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  while (categories.size() > 0) {
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    KJ_IF_SOME(pos, categories.findFirst(',')) {
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      results.add(categories.first(pos));
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      categories = categories.slice(pos + 1);
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    } else {
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      results.add(categories);
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      categories = nullptr;
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    }
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  }
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  return results.releaseAsArray();
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}
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struct PerfettoSession::Impl {
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  kj::OwnFd fd;
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  std::unique_ptr<perfetto::TracingSession> session;
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  Impl(kj::OwnFd dest, kj::StringPtr categories)
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      : fd(kj::mv(dest)),
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        session(createTracingSession(fd.get(), categories)) {
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    session->StartBlocking();
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  }
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};
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PerfettoSession::PerfettoSession(kj::StringPtr path, kj::StringPtr categories)
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    : impl(kj::heap<Impl>(openTraceFile(path), categories)) {}
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PerfettoSession::PerfettoSession(int fd, kj::StringPtr categories)
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    : impl(kj::heap<Impl>(kj::OwnFd(fd), categories)) {}
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PerfettoSession::~PerfettoSession() noexcept(false) {
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  if (impl) {
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    impl->session->FlushBlocking();
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    impl->session->StopBlocking();
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  }
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}
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void PerfettoSession::flush() {
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  if (impl) {
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    impl->session->FlushBlocking();
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  }
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}
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}  // namespace workerd
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#endif  // defined(WORKERD_USE_PERFETTO)