Method FindOrCreatePresent

PresentData/PresentMonTraceConsumer.cpp:2497–2554

}

std::shared_ptr<PresentEvent> PMTraceConsumer::FindOrCreatePresent(EVENT_HEADER const& hdr)
{
    // First, we check if there is an in-progress present that was last
    // operated on from this same thread.
    auto present = FindPresentByThreadId(hdr.ThreadId);
    if (present != nullptr) {
        return present;
    }

    // Next, we look for the oldest present from the same process that may have
    // been deferred by the driver and submitted on a different thread.  Such
    // presents should have only seen present start/stop events so should not
    // have a known PresentMode, etc. yet.
    auto presentsByThisProcess = &mOrderedPresentsByProcessId[hdr.ProcessId];
    for (auto const& pr : *presentsByThisProcess) {
        present = pr.second;
        if (present->DriverThreadId == 0 &&
            present->SeenDxgkPresent == false &&
            present->SeenWin32KEvents == false &&
            present->PresentMode == PresentMode::Unknown) {
            VerboseTraceBeforeModifyingPresent(present.get());
            present->DriverThreadId = hdr.ThreadId;

            // Set this present as the one the driver thread is working on.  We
            // leave it assigned to the one the application thread is working
            // on as well, in case we haven't yet seen application events such
            // as Present::Stop.
            SetThreadPresent(hdr.ThreadId, present);

            return present;
        }
    }

    // If we couldn't find an in-progress present on the same thread/process,
    // then we create a new one and start tracking it from here (unless the
    // user is filtering this process out).
    //
    // This can happen if there was a lost event, or if the present didn't
    // originate from a runtime whose events we're tracking (i.e., DXGI or
    // D3D9) in which case a DxgKrnl event will be the first present-related
    // event we ever see.
    if (IsProcessTrackedForFiltering(hdr.ProcessId)) {
        present = std::make_shared<PresentEvent>();

        VerboseTraceBeforeModifyingPresent(present.get());
        present->PresentStartTime = *(uint64_t*) &hdr.TimeStamp;
        present->ProcessId = hdr.ProcessId;
        present->ThreadId = hdr.ThreadId;

        ApplyPresentFrameType(present);

        TrackPresent(present, presentsByThisProcess);

        return present;
    }

    return nullptr;
}