Name: gvC48267 Date: 12/09/97


We profiled java.net.URLEncoder.encode() with the following URL:
"http://bfc9002:40000/not/real/so/do-not/be/fooled/gadamer/atg-design/prototype-
guidelines/index.html"

It takes 22807 instructions and 70 allocations to encode this URL.
30% of the instructions occur in java.io.ByteArrayOutputStream.toString().

We later saw that BitSet.get()/set() are used in this process and are
synchronized when they don't necessarily have to be. We wrote a test with our
own non-synchronized method calls and got the following performance numbers.

We called BitSet.get() 2048000 times and got these results:
Synchronized: 26124 ms
Unsynchronized: 6594 ms

So synchronization makes BitSet.get() take 4 times as long.

The standard implementation of URLEncoder.encode()
makes N calls to BitSet.get(), where N is the length of the
input string.

Using my version of java.util.BitSet without synchronized get() and set()
methods, I compared the overall performance of URLEncoder.encode()
to its performance using the standard BitSet.

I called URLEncoder.encode() 4000 times on a 100-character URL
and got these results:

Synchronized: 24632 ms
Unsynchronized: 21708 ms

So synchronization makes URLEncoder.encode() take about 13% longer.
(Review ID: 21620)
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