[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

On Case and Performance

  • From: Tim Bray <tbray@t...>
  • To: xml-dev@i...
  • Date: Sat, 06 Sep 1997 14:06:53 -0700

touppercase performance
Recently, I whined:

>What we need is a truly good profiler.  Anyone with a good Java profiler 
>experience to share?  I speeded Lark up substantially with 0.91, just by 
>code-walking and guessing.  This is not the right way to do it. -T.

Disgusted with myself, I went and found the Java Workshop Beta from
java.sun.com, downloaded it (16M!) and ran its profiler.  Well well, 
surprise, Lark was spending 91% of its time in this little routine
that looks up a GI to see if we've seen it before.  And in that 
routine, it was spending most of its time in Character.toUpperCase.

Ouch. The code used to be:
 for (i = 0; i < name.length; i++)
   name[i] = sToUpper[name[i]];

Now it says

 for (i = 0; i < name.length; i++)
   if (name[i] < 127)
     name[i] = sToUpper[name[i]]; // 127-entry upcasing table
   else 
     name[i] = Character.toUpperCase(name[i]);

Note that toUpperCase is called only in the case when non-ASCII 
characters show up in GI/Attribute/Entity names.

Resulting performance improvement in Lark, in processing the XML spec:
a factor of 11.9.

The Sun profiler is not quite as slick as gprof of yore, but it's
not bad at all. -T.



xml-dev: A list for W3C XML Developers
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/
To unsubscribe, send to majordomo@i... the following message;
unsubscribe xml-dev
List coordinator, Henry Rzepa (rzepa@i...)


PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
Email
First Name
Last Name
Company
Subscribe in XML format
RSS 2.0
Atom 0.3
 

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.


Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.