重用object fields以加速Java處理器之執行效率

Abstract

在Java處理器執行Java程式時，需要很多的執行時間和計憶體的存取來完成object field access的動作。在此篇論文中，我們提出對於object field access的加速方法是利用一硬體的緩衝區，稱作object cache，來儲存先前已經被存取過的object field的值。這種object cache不但能加速object field access的動作，並且支援garbage collection，保證在發生garbage collection時，依然可由object cache拿到正確的資料。藉由透過Trace-driven的方式對SPECjvm98標竿程式進行模擬，結果顯示在昇陽的picoJava-II處理器中加入我們所提出的object cache，將可使object field access的速度提升3.3倍。

The operations of object field accesses in the Java processor require many clock cycles and memory references. Our approach of improving the performance of object field accesses is to cache the values of object fields of previous execution in hardware buffers, called object cache. In this thesis, object cache that can reduce the object field access time and support garbage collection, is proposed. A detailed trace-driven simulation of the proposed method on SPECjvm98 benchmark show that our proposed method can achieve 3.3 speedup over Sun’s picoJava-II on object field accesses.