Re: [jira] Commented: (HARMONY-6045) [classlib] [luni] Optimize java.lang.String.toUpperCase(), String.toLowerCase() and String sharing for more performance gains

[Regis]

I found at String:619, it should be
return codePoint - ('a' - 'A');
and at String:595, it should be
return (char) (ch + ('a' - 'A'));

Is it right? And for private char compareValue, could we return directly if it's 
ASCII lower case, like:
    private char compareValue(char ch) {
        if (ch < 128) {
            if ('A' <= ch && ch <= 'Z') {
                return (char) (ch + ('a' - 'A'));
            }
            return ch;
        }
        return Character.toLowerCase(Character.toUpperCase(ch));
    }

Regis wrote:
Kevin Zhou wrote:
It looks good! :)

Not so good, it cause test failures. seems most of them are failed in 
compareToIgnoreCase and toUpperCase. Would you please take a look at it?


On Mon, Apr 20, 2009 at 1:53 PM, Regis <xu.re...@gmail.com> wrote:

Regis wrote:

Kevin Zhou wrote:

Previously, it is proved by using benchmarks like Specjbb.
Since it's been a long time I don't really remember the accurate
statistics
of how much improvements it brings.

All right, I will try to write some micro benchmarks :)

I have attached a very simple micro benchmark for converting case of 
ASCII
character. The patch seems great:

* before the patch HARMONY-6045v2.diff:
String.toUpperCase
count per cycle: 1000000
2779 2727 2706 2768 2745
String.toLowerCase
count per cycle: 1000000
1929 1934 1940 1963 1911

* after the patch:
String.toUpperCase
count per cycle: 1000000
1380 1350 1355 1359 1423
String.toLowerCase
count per cycle: 1000000
1182 1189 1189 1177 1171

* RI 1.5:
String.toUpperCase
count per cycle: 1000000
3123 3181 3132 3117 3156
String.toLowerCase
count per cycle: 1000000
3375 3328 3394 3336 3390

for String.toUpperCase, average from 2745 to 1373.4, improve almost 100%
for String.toLowerCase, average from 1935.4 to 1181.6, improve 64%

But I noticed there are tests failed after patch:
org.apache.harmony.luni.tests.java.lang.Character_UnicodeBlockTest
org.apache.harmony.luni.tests.java.lang.String2Test

org.apache.harmony.luni.tests.internal.net.www.protocol.file.FileURLConnectionTest 

org.apache.harmony.luni.tests.java.util.Arrays2Test
org.apache.harmony.luni.tests.java.net.URITest
org.apache.harmony.luni.tests.java.net.URLConnectionTest


--
Best Regards,
Regis.






--
Best Regards,
Regis.