In MyFaces Core another nice feature was introduced since version 2.1.10. The idea is quite simple, just try to minimize the additional white spaces in a html page to reduce its size. Usually the code generated by renderers does not contains unnecessary spaces, but the code that comes directly from html markup in facelets comes straight from the xhtml or xml file used.
The trick behind this feature is enable/disable it as a do inside facelets compiler option. Just add this into your WEB-INF/faces-config.xml file:
<faces-config xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-facesconfig_2_1.xsd"
version="2.1">
<faces-config-extension>
<facelets-processing>
<file-extension>.xhtml</file-extension>
<process-as>xhtml</process-as>
<oam-compress-spaces>true</oam-compress-spaces>
</facelets-processing>
</faces-config>
That's it. Now, facelets compiler will try to reduce or remove spaces/tabs when they are not necessary, following the rules for html white space compression, to avoid change the apperance of the page. In simple words, this means when necessary it replace multiple continuous spaces with just one or remove all of them. It also try to use '\n' characters when possible, to make easier read the page markup once compressed.
Since this optimization is done in facelets compiler, the effort to reduce white spaces is just done once, so all your pages will not impose additional CPU or memory overhead. It's more, it reduce the memory and CPU resources required to render a page, so this can give a little boost to your application.
Note this only affects the spaces generated by plain html markup, if you have a component renderer that output some spaces, those ones are not preprocessed.
miércoles, 5 de diciembre de 2012
viernes, 18 de mayo de 2012
Understanding JSF 2 and Wicket: Performance Comparison
See the updated comparison for 2013 at JSFCentral:
Suggestions, comments, critics or any discussion about it can be posted below.
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Performance is important in a web
framework, even though it is certainly not the only consideration.
But anyway, it is a topic that deserves an in-deep analysis. This is
not a topic that can be reduced to just some few numbers, instead,
web frameworks try to make a balance performance and other aspects
like usability, extensibility, and much more.
In the last year (2011-2012), a
lot of performance improvements has been done inside Apache MyFaces
JSF Implementation (aka MyFaces Core). To see how good are the
improvements, a comparison was done against a similar Java Web
Framework like Wicket. In order to save some work, the reference
application provided in this link was used:
Fortunately, the
wicket guys have been so kind to updated the original application
running with 1.4.x to version 1.5.x, so we'll compare JSF against
two Wicket versions (1.4.20 and 1.5.5). A comparison against Tapestry
might happen later. In the end, the intention is to look at how JSF
works from a performance perspective, so Wicket will be taken only as
a reference point.
Checking the code
provided in that blog and the related data, some rather serious
problems were discovered. Anyway, the code example is good enough to
reuse it, while obviously fixing the detected problems. The updated
code, configuration used, detailed documentation and experimental
data can be found in the internet (github).
Detailed Document
(21 pages, PDF Format)
Keep in mind that
this blog entry is just a resume of the detailed document.
A
good benchmark should consider different aspects. So, for this
comparison, the following aspects has been checked:
- Speed benchmark: Check the speed of the code under different situations.
- Memory Consumption : Involves checking how much memory does the application need to allocate for a specific task, and how the application behaves under low memory conditions.
- Session Size : Check how much memory is used to store the session.
It
is quite obvious why these three aspects should be considered:
- If the framework is fast it will process more requests with less CPU consumption.
- If the framework requires less memory, less time will be used in garbage collection and the framework will perform better under stress conditions.
- If it uses less memory as session storage, it will be able to serve more users with the same memory size, and if the session is stored somewhere (database, file, memory cache... ), less time will be used in processing that information (usually serialization/deserialization and dealing with I/O operations).
For the guys who are
impatient these are the results: NOTE: This
information is just related to the test application used and its
results cannot be generalized. If you want to see the underlying
discussion please read the detailed document.
Comparing MyFaces
and Mojarra in the graph, you can see MyFaces 2.1.7 has become the
fastest by a wide margin (more than 40%!). Comparing Wicket 1.4.20
and 1.5.5 you can see 1.4.20 is faster. In this case, a better
programming model in 1.5.5 has cost some speed. In Wicket, disk
storage (default) and http session storage has different trade-offs.
In
this case, MyFaces uses a lot less memory to do the same task and the
memory used between Mojarra and Wicket 1.4.20 is more or less the
same. Wicket disk storage requires more memory than session storage,
because the pages need to be saved and restored from disk. Most
memory is allocated by Wicket 1.5.5, but it is interesting that there
is no significant difference between disk storage and session
storage.
From a memory
perspective, MyFaces is the winner but note that allocating more or
less memory doesn't say much because part of this allocated memory
could have a short life, but it is relevant if the web server has not
a lot of memory. In a few words, the less bytes and objects allocated
the better.
JSF average view
size is very small compared to the user session size, imposing a
reasonable overhead. In this case, MyFaces do the best job, keeping
the state size very small, and the important part here is note that
the state overhead for JSF grows very slowly. In Wicket case, since
it stores the whole page into the state, it easily grow more quickly.
CONCLUSION
Definitively JSF 2.0 was a big
move in the right direction. JSF session size overhead is
significantly lower than Wicket. MyFaces Core 2.1.7 looks very well
from a performance perspective against a web framework like Wicket.
In the end, MyFaces provides the better trade-off between CPU usage
and session size. The bet of Wicket on disk storage is good, but the
JSF bet on partial state is even better. MyFaces also provides the
lowest memory usage, which allows it to perform better in
environments with limited CPU and memory.
Comparing Wicket 1.4 vs Wicket
1.5, it seems that the improvement in its programming model is taking
a toll. In my opinion it is something completely reasonable. A good
web framework needs to balance different aspects in order to keep
evolving over the time. Including more assisting code usually means
lower response times, but it could improve developer productivity.
This is not the end
of the story. Web frameworks will keep improving and the hope is this
information can be useful to find new ways to enhance them (community
over code is the Apache way). Remember: performance is just one
aspect that you have to consider when choosing a web framework;
usually it is necessary to strike a balance between this and several
other aspects.
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