// This value is specified in number of frames.  Log frame stats at most
// every half hour.
enum { LOG_FRAME_STATS_PERIOD =  30*60*60 };

void SurfaceFlinger::postFrame() {
    const auto display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
    if (display && getHwComposer().isConnected(display->getPhysicalId())) {
        uint32_t flipCount = display->getPageFlipCount();
        if (flipCount % LOG_FRAME_STATS_PERIOD == 0) {
            logFrameStats();
        }
    }
}

• 最快每半小时调用 logFrameStats()。
• 60 帧/秒，306060/60 = 1800 秒。