I reboot my laptop as infrequently as possible - which means that I keep Firefox running for weeks without restarting. At least, I would prefer to. But the longer it runs, the more memory it gobbles. The only way to reclaim it is to reboot.

So when I read about the tab-isolation feature in Googles new Chrome browser which uses a separate process for each tab, it peaked my interest. I installed Chrome and tried a very quick (and not very scientific) test, as described below.

Firefox had been open for a few days and currently had 8 tabs open. I am sure many tabs had been opened and closed in the time it had been running. It was consuming 138M of memory according to Task Manager.

I started Chrome and opened the same 8 URLs. Going back to Task Manager and adding up the memory usage of the 9 Chrome processes resulted in 152M consumed. I’m sure that closing and re-opening Firefox would have resulted in less that the 138M of RAM that I mentioned earlier. So, as many have predicted, the memory usage in Chrome is much higher than Firefox.

Next I tried closing 5 of the 8 tabs in Firefox. Memory consumption, as expected, barely moved - dropping only to 132M and reclaiming 4.3% of the total memory allocation. Closing the same 5 tabs in Chrome reduced memory usage to 86M - reclaiming 43% of the total memory used.

This is enough evidence for me to conclude that the tab/process isolation model would work well for my typical usage. I don’t envision abandoning Firefox (or the wealth of available plugins) anytime soon. But I’ll be keeping a close eye on the progress Google makes with Chrome.

I hope to find time for a more rigorous (and scientific) test in the future.

When customers are preparing to buy our load testing software, they frequently ask “How many users should I load test my system with?”. Naturally, we can’t answer that question without a lot more information about the performance requirements and the expected usage of the web application. Read the rest of this entry »

Ok - so you’ve spent months putting together a shiny new mission-critical web application, complete with multiple web servers, a few application and/or database servers. There is a load balancer in the mix or maybe you are using Microsoft NLB (Network Load Balancing). The system is nearly ready to deploy and it is time to run a load test. The first inclination is to fire up the load testing tool and throw the maximum expected load at the entire cluster. After all, there is no sense in wasting time with the smaller pieces, right? Wrong. Read the rest of this entry »

One of the most common load testing mistakes made by beginners is their configuration of the user ramp rate. This is best illustrated with an example configuration that we see frequently. Read the rest of this entry »

The latest installment in our PHP performance series takes a look at the open source APC module, which is described this way: “APC is a free, open, and robust framework for caching and optimizing PHP intermediate code.” The results were dramatic, as the module increased the user capacity of the reference PHP application by 2.8 times.

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Load Testing SugarCRM and the Zend Platform

The performance of our reference PHP application under load (a default SugarCRM installation) showed a 140% increase, measured by total system capacity, after installation of the Zend Platform.

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Determining the CPU cost of virtualization with VMware ESX

The
performance of our
reference application under
load (a default SugarCRM
installation) on a virtualized server showed a 14% decrease, measured
by total system
capacity, compared to the same system running natively on equivalent
hardware.

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Load Testing SugarCRM and the Zend Optimizer

This article measures the performance impact of the Zend Optimizer on a real-world processor-bound PHP application (SugarCRM) under load. Our measure of performance is user capacity. We define that as the number of simultaneous users that the system can support while meeting the specified performance criteria. The performance critera for this test require that all pages load within 6 seconds and no errors are encountered in the application.

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Evaluating Apple’s Browser Performance Claims in The Real World

On June 11th, Apple released a Windows beta version of its OSX web browser, Safari 3.0, claiming its the “fastest browser on Windows”. The claims were based on the results Apple found while running the iBench benchmark from Ziff Davis, with separate measurements for HTML, JavaScript performance, and application start time. While benchmarks are invaluable for performance evaluation, we set out to see if those claims would make a difference in actual browser usage.

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Measuring the Performance Impact of Virtualizing a Web Application Server

Virtualization is hot. Over the past few months, it would be difficult to pick an IT magazine out of my stack that does not have an article on Virtualization. Even in our small company, we have two VMware servers. This allowed us to reduce 9 underutilized servers down to two physical machines. Because the original severs were severely underutilized, the virtualized servers actually perform better (running on newer hardware). They are easier to manage - especially for backups. We have reduced the risk of configuration changes, software installs and upgrades by taking snapshots before these procedures. What’s not to like?

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