Hello Friends,
For those who are interested in Open Source Java Profiling tool.
Introduction
Jensor is a light-weight, low-overhead Java profiler written entirely in Java. Jensor is built on ByteCode Instrumentation (BCI) technology. Jensor provides innovative analysis techniques that help to detect and eliminate bottlenecks in Java applications. More interesting modules are as follows
* Tagging Engine
Allows breakup of data by user-defined tags. Tags can be created to view a business or technical or both perspectives. Tagging Engine thus provides for Business as well as Technical analysis based on the same underlying data.
* JVM Replay
Provides animated display of events that occured in the JVM. The replay thus creates a time and space perspective of methods executed in the JVM. This feature is useful in debugging reliability of Java applications.
* Pattern Analysis
Jensor discovers method call patterns based on the call graph sequence. Optimizing a pattern as opposed to a method provides cascading performance advantages across entire JVM.
http://jensor.sourceforge.net/
Wednesday, October 28, 2009
Open Source Network Profiler
Hello Friends,
Hope many of you might know about this network profiler which is open source tool developed by TCS Performance Engineering Research Center.
Introductory Information
WANem is a Wide Area Network Emulator, meant to provide a real experience of a Wide Area Network/Internet, during application development / testing over a LAN environment. Typically application developers develop applications on a LAN while the intended purpose for the same could be, clients accessing the same over the WAN or even the Internet. WANem thus allows the application development team to setup a transparent application gateway which can be used to simulate WAN characteristics like Network delay, Packet loss, Packet corruption, Disconnections, Packet re-ordering, Jitter, etc. WANem can be used to simulate Wide Area Network conditions for Data/Voice traffic and is released under the widely acceptable GPL v2 license. WANem thus provides emulation of Wide Area Network characteristics and thus allows data/voice applications to be tested in a realistic WAN environment before they are moved into production at an affordable cost. WANem is built on top of other FLOSS[Free Libre and OpenSource] components and like other intelligent FLOSS projects has chosen not to re-invent the wheel as much as possible.
For more details....please go through
http://wanem.sourceforge.net/
Hope many of you might know about this network profiler which is open source tool developed by TCS Performance Engineering Research Center.
Introductory Information
WANem is a Wide Area Network Emulator, meant to provide a real experience of a Wide Area Network/Internet, during application development / testing over a LAN environment. Typically application developers develop applications on a LAN while the intended purpose for the same could be, clients accessing the same over the WAN or even the Internet. WANem thus allows the application development team to setup a transparent application gateway which can be used to simulate WAN characteristics like Network delay, Packet loss, Packet corruption, Disconnections, Packet re-ordering, Jitter, etc. WANem can be used to simulate Wide Area Network conditions for Data/Voice traffic and is released under the widely acceptable GPL v2 license. WANem thus provides emulation of Wide Area Network characteristics and thus allows data/voice applications to be tested in a realistic WAN environment before they are moved into production at an affordable cost. WANem is built on top of other FLOSS[Free Libre and OpenSource] components and like other intelligent FLOSS projects has chosen not to re-invent the wheel as much as possible.
For more details....please go through
http://wanem.sourceforge.net/
Monday, September 7, 2009
HTTP 1.1 : Caching in HTTP
Hello Friends,
I found an article on HTTP Caching which seems to be useful. I have copied some portion of the article for your reference.
HTTP is typically used for distributed information systems, where performance can be improved by the use of response caches. The HTTP/1.1 protocol includes a number of elements intended to make caching work as well as possible. Because these elements are inextricable from other aspects of the protocol, and because they interact with each other, it is useful to describe the basic caching design of HTTP separately from the detailed descriptions of methods, headers, response codes, etc.
Caching would be useless if it did not significantly improve performance. The goal of caching in HTTP/1.1 is to eliminate the need to send requests in many cases, and to eliminate the need to send full responses in many other cases. The former reduces the number of network round-trips required for many operations; we use an "expiration" mechanism for this purpose (see section 13.2). The latter reduces network bandwidth requirements; we use a "validation" mechanism for this purpose (see section 13.3).
For more details, please go through this link
http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
I found an article on HTTP Caching which seems to be useful. I have copied some portion of the article for your reference.
HTTP is typically used for distributed information systems, where performance can be improved by the use of response caches. The HTTP/1.1 protocol includes a number of elements intended to make caching work as well as possible. Because these elements are inextricable from other aspects of the protocol, and because they interact with each other, it is useful to describe the basic caching design of HTTP separately from the detailed descriptions of methods, headers, response codes, etc.
Caching would be useless if it did not significantly improve performance. The goal of caching in HTTP/1.1 is to eliminate the need to send requests in many cases, and to eliminate the need to send full responses in many other cases. The former reduces the number of network round-trips required for many operations; we use an "expiration" mechanism for this purpose (see section 13.2). The latter reduces network bandwidth requirements; we use a "validation" mechanism for this purpose (see section 13.3).
For more details, please go through this link
http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
Sunday, August 23, 2009
Why doesn't free memory go down on Linux?
Hello Friends,
I have a Linux OS with a java application using 2 GB on a whole and 1.5 GB Memory for oracle database on a 8 GB RAM machine. I am in a situation where i see free memory to be very low i.e. just 35 MB. I had a look at all the available processes but none of the processes are consuming so much memory which is missing. Do you think it is bug? No, it is a feature provided in Redhat Linux.
You can find a good explanation about the situation i have explained above in the below article.
http://sourcefrog.net/weblog/software/linux-kernel/free-mem.html
I have a Linux OS with a java application using 2 GB on a whole and 1.5 GB Memory for oracle database on a 8 GB RAM machine. I am in a situation where i see free memory to be very low i.e. just 35 MB. I had a look at all the available processes but none of the processes are consuming so much memory which is missing. Do you think it is bug? No, it is a feature provided in Redhat Linux.
You can find a good explanation about the situation i have explained above in the below article.
http://sourcefrog.net/weblog/software/linux-kernel/free-mem.html
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