 |
Sun, bullets, and feet
Posted by jacksjpt on February 04, 2004 at 11:23 AM | Comments (3)
In January's Java Performance Tuning newsletter there are several interesting news items. Of course we had the usual range of tool vendor and benchmark announcements; what I consider to be "background news", because they are usually there each month. (Naturally we only list the performance announcements, and even there only the interesting ones.) Apart from those announcements, there was the 9 language benchmark which didn't show Java as overall the fastest language only because Sun shot itself in the performance foot by insisting on not addressing the "strict" Math performance for so many years. They've known about it for years, and even designed more efficient support into the core classes, but neglected to turn on support for the efficient mode. Of course, Sun has limited resources, so some things will always slip by them. But in this case they clearly understood they were making Math functions inefficient, they added the underlying support for an efficient alternative, and didn't enable it even though quite a few comments have pointed it out. Which is pretty annoying.
For me, the most interesting of items in the news was the server side discussion which floated the idea of pushing NIO support into J2EE. What a wealth of information. NIO select support costing 5% to 30% overhead compared to the blocked multi-thread model came as a real surprise to me. Though maybe it shouldn't since a blocked thread mostly only takes up non-CPU resources, while the Select multiplexing model explicitly exchanges those per-thread resources with active socket set management. I think the 5% mark is probably the more accurate though, because excellent as a product Jetty is, I've noticed several inefficiencies that it has, along with many webservers (see this old study if you want to understand how even minor effects can dramatically affect the scalability of webservers). In fact we use Jetty in our performance training classes, and profiling the socket transfers is quite instructive for our students. And that's not to say I wouldn't use it in production. On the contrary, if it fitted the functional requirements I'd certainly test its performance against the other possible solutions.
Other than that, you might also want to check out the fail fast article if you haven't noticed the ConcurrentModificationException possibilities inherent in using the List iterators, and our other columns are also quite interesting:
- We list all the latest Java performance related news and articles
- "more proof that Java is going from strength to strength. Now that's a nice way to start 2004."
- Learning From Code: Fast Fail Iterators.
- "What is a mysterious field called
modCount doing in the List Iterator classes? How can we efficiently handle iterating over collections when another thread may be updating the collection at the same time? Read on ..."
- The roundup of performance discussions over the last month. Kirk covers session beans, timing distributed calls, garbage collection and more
- "Yet more proof that the engineers at Sun fully realized that optimizers such as HotSpot are sensitive to coding style and with that realization, built HotSpot with good coding practices in mind "
- Javva The Hutt rambles through performance past, present and future. This month Javva has a "wow!" moment, and gets visted by Agent Smith
- "Agent Smith visited us. You know, the one from the Matrix? Black shades, wire coil hanging behind his ear, precise speech patterns, shady motives."
- This month's interview with Bela Ban, lead for JBossCache
- "what we want to do here is to use our transactional replicated cache to actually keep the cached entity beans in memory. This will greatly improve performance"
- Question of the Month asks about profiling J2EE applications
- "J2EE applications are often of such complexity that there can be bottlenecks which are difficult to identify without jumping through hoops"
- All the lastest Java performance tips extracted in concise form
- "Some small optimizations (like turning logging down) can yield huge gains"
- A new cartoon by "profiler". This month: Lazy Initialization
Bookmark blog post: del.icio.us Digg DZone Furl Reddit
Comments
Comments are listed in date ascending order (oldest first) | Post Comment
-
Can we switch "faster math" on?
"they added the underlying support for an efficient alternative, and didn't enable it even though quite a few comments have pointed it out. "
Jack, is there a way to switch to faster math? Math vs. StrictMath hasn't made a speed difference for me (jsdk 1.4.1).
Thanks,
Dave
Posted by: dwalend on February 09, 2004 at 08:27 AM
-
wow power leveling
wow powerleveling
wow power leveling
wow gold
wow items
feelingame.com
wow tips
Most Valuable WOW Power Leveling Service
wow power leveling faq
cheap wow power leveling
wow power leveling
wow powerleveling
wow power lvl
Posted by: wowleveling11 on December 14, 2007 at 07:32 PM
-
网络营销软件
网络营销软件
网络营销软件
群发软件
群发软件
---
群发软件
网络营销软件
论坛群发软件
网站排名软件
群发软件
推广小助手破解版
论坛群发软件
网站排名软件
群发软件
推荐给你很好的群发软件和信息群发软件和供求群发软件
推荐给你很好的群发软件和信息群发软件和供求群发软件博客群发软件网络营销软件网络营销软件
网站排名软件网站排名软件网站优化软件信息群发软件信息群发软件信息群发软件论坛群发软件网站推广软件网站推广软件博客群发软件博客群发软件
群发软件
网络营销软件
网站推广软件
群发软件群发软件博客群发软件论坛群发软件网络营销软件论坛群发软件
信息群发软件推广软件网站推广软件网络营销软件网站推广软件群发软件网站排名软件网站推广软件博客群发软件论坛群发软件群发软件网站排名软件网站推广软件博客群发软件论坛群发软件
网站排名软件
博客群发软件
网站排名软件
网站推广软件
群发软件信息群发软件
免费论坛群发软件
论坛群发软件
网站排名软件
免费博客群发软件
网站推广软件
群发软件
博客群发软件
网站排名软件
网站推广软件
群发软件信息群发软件
免费论坛群发软件
论坛群发软件
网站排名软件
免费博客群发软件
博客群发软件
信息群发软件
论坛群发软件
信息群发软件
博客群发软件
qq群发软件
邮件群发软件
博客群建软件
企业名录搜索软件
信息群发软件
邮件群发软件
论坛群发软件
博客群发软件
网站推广软件
网络营销软件
全能营销破解版
网络营销软件
论坛群发软件
论坛群发软件
论坛群发软件
网络营销软件
信息群发软件
信息群发软件
信息群发软件
群发软件
论坛群发软件
Posted by: sun98989 on December 30, 2007 at 05:40 AM
|