Android的最佳缓冲区大小 [英] Android Optimal Buffer Size

问题描述

在Java中的32 KB的最佳缓冲区大小是所使用的CPU架构完全基于。在Android手机并Dalvik虚拟机动态地了解CPU，以获得最大的缓冲区大小无关的许多不同的手机在那里的正确缓存？如果是的话，我将如何可以认识到这一点在运行时？

In java there is an optimal buffer size of 32 Kb which is based solely on the cpu architecture being used. On Android phones does the Dalvik VM dynamically know the proper cache of the cpu to get the largest buffer size independent of the many different phones out there? If so how would I figure that out at runtime?

说，我想通过使缓冲最大的也可以是，也以最快的速度优化录音活动。我知道你可以得到关于最佳尺寸的最小尺寸，但什么呢？

Say I want to optimize a audio recording activity by making the buffer the largest it can be and also the fastest. I know you can get the minimal size for it but what about the optimal size?

推荐答案

也许这取决于你拥有或心灵什么设备。

Maybe it depends on what device you have or mind.

然而，实验， 8K＆LT;缓冲区的大小和LT; 32K 确实运作良好，有8K下显著的性能提升。有些有趣的是，与缓存一些数据> 64K显示，在64K缓冲区

However, experimentally, 8K < buffer size < 32K does work well and there are significant performance improvements under 8K. Somewhat interesting is that some data with buffer > 64K showed poorer performance than data with under 64K buffer

（我已经在几款Android设备的测试，并试图读取各种缓冲区大小为20MB的二进制文件。）

(I've tested on several android devices and tried to read 20MB binary file with various buffer size.)

下面是EXP的结果，你会更好，如果你想转换成数据，pretty的形式将它们粘贴至S preadsheet。头装置的的缓冲区大小的和单位的毫秒的

Here's exp result and you'd better to paste them to spreadsheet if you wanna convert data in pretty form. header means buffer size and units are millisecond

图：<一href="http://fb.com/photo.php?fbid=468345876512381">http://fb.com/photo.php?fbid=468345876512381

                   128     256     512     1K      2K      4K      8K      16K     32K     64K     128K    256K    512K    1M      2M      4M      8M      16M
    Galaxy S       4047    3060    269     155     100     65      64      52      51      45      47      50      49      43      44      46      45      58
    Optimus LTE    1178    617     322     172     101     65      47      42      41      35      36      39      44      61      56      51      72      60
    HTC EVO        3971    1884    941     480     251     141     95      69      56      50      48      55      50      49      48      48      48      47         
    Galaxy S2      750     383     210     123     74      50      41      37      35      34      34      37      39      44      46      44      45      44
    Galaxy Nexus   2272    1216    659     341     187     108     70      52      41      38      38      45      44      54      56      66      68      58
    Galaxy Note    1549    799     404     220     127     75      58      54      52      56      52      45      44      62      43      39      44      46

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InputStream in = openFileInput(FILE_NAME);
startTime = System.currentTimeMillis();

while (in.read(buffer) > 0) {
    readCount++;
}

elapsedTime = System.currentTimeMillis() - startTime;

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