Welcome!

Cloud Security Authors: Elizabeth White, Tim Hinds, Dan Sarel, Derek Weeks, David Balaban

Related Topics: Java IoT, IoT User Interface

Java IoT: Article

The Cost of an Exception

A closer look at the costs of throwing exceptions

Recently there was a bigger discussion at dynaTrace around the cost of exceptions. When working with customers we very often find a lot of exceptions they are not aware of. After removing these exceptions, the code runs significantly faster than before. This creates the assumption that using exceptions in your code comes with a significant performance overhead. The implication would be that you better avoid using exceptions. As exceptions are an important construct for handling error situation, avoiding exceptions completely does not seem to be good solution. All in all this was reason enough to have a closer look at the costs of throwing exceptions.

The Experiment
I based my experiment on a simple piece of code that randomly throws an exception. This is not a really scientifically-profound measurement and we also don’t know what the HotSpot compiler does with the code as it runs. Nevertheless it should provide us with some basic insights.

public class ExceptionTest {

public long maxLevel = 20;

public static void main (String ... args){

ExceptionTest test = new ExceptionTest();

long start = System.currentTimeMillis();
int count = 10000;
for (int i= 0; i < count; i++){
try {
test.doTest(2, 0);
}catch (Exception ex){
//        ex.getStackTrace();
}
}
long diff = System.currentTimeMillis() - start;
System.out.println(String.format("Average time for invocation: %1$.5f",((double) diff)/count));
}

public void doTest (int i, int level){
if (level < maxLevel){
try {
doTest (i, ++level);
}
catch (Exception ex){
//        ex.getStackTrace();
throw new RuntimeException ("UUUPS", ex);
}
}
else {
if (i > 1) {
throw new RuntimeException("Ups".substring(0, 3));
}
}
}
}

The Result
The result was very interesting. The cost of throwing and catching an exception seems to be rather low. In my sample it was about 0.002ms per Exception. This can more or less be neglected unless you really throw too many exceptions – and too many means we are talking about 100.000 or more.

While these results show that exception handling itself is not affecting code performance, it leaves open the question: what is responsible for the huge performance impact of exceptions? So obviously I was missing something – something important.

After thinking about it again, I realized that I was missing an important part of exception handling. I missed out the part on what you do when exceptions occur. In most cases you – hopefully – do not just catch the exception and that’s it. Normally you try to compensate for the problem and keep the application functioning for your end users. So the point I was missing was the compensation code that is executed for handling an exception. Depending on what this code is doing the performance penalty can become quite significant. In some cases this might mean retrying to connect to a server in other cases it might mean using a default fallback solution that is providing a far less-performing solution.

While this seemed to be a good explanation for the behavior we saw in many scenarios, I thought I am not done yet with the analysis. I had the feeling that there is something else that I was missing here.

Stack Traces
Still curious about this problem I looked into how the situation changes when I collect stack traces. This is what very often happens. You log an exception and its stack trace to try to figure out what the problem is.

I therefore modified my code to now get the stack trace of an exception as well. This changed the situation dramatically. Getting the stack trace of an exception had a 10x higher impact on the performance than just catching and throwing them. So while stack traces help to understand where and possibly also why a problem occurred, they come with a performance penalty.

The impact here is often very high as we are not talking about a single stack trace. In most cases exceptions are thrown – and caught – at multiple levels. Let us look at a simple example of a Web Service client connecting to a server. First there is an exception at the Java library level for the failed connection. Then there is a framework exception for the failed client and then there might be an application-level exception that some business logic invocation failed. This now sums up to three stack traces being collected.

In most cases you should see them in your log files or application output. Writing these potentially long stack traces again comes with some performance impact. At least you normally see and you can react to them if you look at your log files regularly – which is something you do, don’t you? ;-)

In some cases I have seen even worse behavior due to some incorrect logging code. Instead of checking whether a certain log level is enabled by calling log.isxxEnabled () first, developers just call logging methods. When this happens, logging code is always executed including getting stack traces of exceptions. As the log level however is set too low they never show up anywhere you might not even be aware of them. Checking for log levels first should be a general rule as it also avoids unnecessary object creation.

Conclusion
Not using exceptions because of their potential performance impact is a bad idea. Exceptions help to provide a uniform way to cope with runtime problems and they help to write clean code. You however need to trace the number of exceptions that are thrown in your code. Although they might be caught they can still have a significant performance impact. In dynaTrace we, by default, track thrown exceptions – and in many cases people are surprised by what is going on in their code and what the performance impact is in resolving them.

While exception usage is good you should avoid capturing too many stack traces. In many cases they are not even necessary to understand the problem – especially if they cover a problem you already expect. The exception message therefore might prove as being enough information. I get enough out of a Connection refused message so I do not need the full stack trace into the internal of the java.net call stack.

Related reading:

  1. Application Performance Monitoring in production – A Step-by-Step Guide – Part 1 // Setting up Application Performance Monitoring is a big task,...
  2. The impact of Garbage Collection on Java performance // In my last post I explained what a major...
  3. Top 10 Performance Problems taken from Zappos, Monster, Thomson and Co For a recent edition of the Swiss Computerworld Magazine we...
  4. Top 10 Client-Side Performance Problems in Web 2.0 Inspired by the Top 10 Performance Problems post which focuses...
  5. Real Life Ajax Troubleshooting Guide One of our clients occasionally runs into the following problem...

 

More Stories By Alois Reitbauer

Alois Reitbauer works as a Technology Strategist for dynaTrace Software where he is leading the Methods and Technology team. As part of the R&D team he influences the dynaTrace product strategy and works closely with key customers in implementing performance management solution for the entire lifecylce. Alois has 10 years experience as architect and developer in the Java and .NET space. He is a frequent speaker at technology conferences on performance and architecture related topics and regularly publishes articles blogs on blog.dynatrace.com

@ThingsExpo Stories
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
You deployed your app with the Bluemix PaaS and it's gaining some serious traction, so it's time to make some tweaks. Did you design your application in a way that it can scale in the cloud? Were you even thinking about the cloud when you built the app? If not, chances are your app is going to break. Check out this webcast to learn various techniques for designing applications that will scale successfully in Bluemix, for the confidence you need to take your apps to the next level and beyond.
We’ve worked with dozens of early adopters across numerous industries and will debunk common misperceptions, which starts with understanding that many of the connected products we’ll use over the next 5 years are already products, they’re just not yet connected. With an IoT product, time-in-market provides much more essential feedback than ever before. Innovation comes from what you do with the data that the connected product provides in order to enhance the customer experience and optimize busi...
Increasing IoT connectivity is forcing enterprises to find elegant solutions to organize and visualize all incoming data from these connected devices with re-configurable dashboard widgets to effectively allow rapid decision-making for everything from immediate actions in tactical situations to strategic analysis and reporting. In his session at 18th Cloud Expo, Shikhir Singh, Senior Developer Relations Manager at Sencha, will discuss how to create HTML5 dashboards that interact with IoT devic...
Artificial Intelligence has the potential to massively disrupt IoT. In his session at 18th Cloud Expo, AJ Abdallat, CEO of Beyond AI, will discuss what the five main drivers are in Artificial Intelligence that could shape the future of the Internet of Things. AJ Abdallat is CEO of Beyond AI. He has over 20 years of management experience in the fields of artificial intelligence, sensors, instruments, devices and software for telecommunications, life sciences, environmental monitoring, process...
SYS-CON Events announced today that Ericsson has been named “Gold Sponsor” of SYS-CON's @ThingsExpo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. Ericsson is a world leader in the rapidly changing environment of communications technology – providing equipment, software and services to enable transformation through mobility. Some 40 percent of global mobile traffic runs through networks we have supplied. More than 1 billion subscribers around the world re...
Digital payments using wearable devices such as smart watches, fitness trackers, and payment wristbands are an increasing area of focus for industry participants, and consumer acceptance from early trials and deployments has encouraged some of the biggest names in technology and banking to continue their push to drive growth in this nascent market. Wearable payment systems may utilize near field communication (NFC), radio frequency identification (RFID), or quick response (QR) codes and barcodes...
SYS-CON Events announced today that Fusion, a leading provider of cloud services, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry's single source for the cloud. Fusion's advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including cloud...
SYS-CON Events announced today that Peak 10, Inc., a national IT infrastructure and cloud services provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Peak 10 provides reliable, tailored data center and network services, cloud and managed services. Its solutions are designed to scale and adapt to customers’ changing business needs, enabling them to lower costs, improve performance and focus inter...
In his session at @ThingsExpo, Chris Klein, CEO and Co-founder of Rachio, will discuss next generation communities that are using IoT to create more sustainable, intelligent communities. One example is Sterling Ranch, a 10,000 home development that – with the help of Siemens – will integrate IoT technology into the community to provide residents with energy and water savings as well as intelligent security. Everything from stop lights to sprinkler systems to building infrastructures will run ef...
So, you bought into the current machine learning craze and went on to collect millions/billions of records from this promising new data source. Now, what do you do with them? Too often, the abundance of data quickly turns into an abundance of problems. How do you extract that "magic essence" from your data without falling into the common pitfalls? In her session at @ThingsExpo, Natalia Ponomareva, Software Engineer at Google, will provide tips on how to be successful in large scale machine lear...
SYS-CON Events announced today that DatacenterDynamics has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY. DatacenterDynamics is a brand of DCD Group, a global B2B media and publishing company that develops products to help senior professionals in the world's most ICT dependent organizations make risk-based infrastructure and capacity decisions.
The IoT has the potential to create a renaissance of manufacturing in the US and elsewhere. In his session at 18th Cloud Expo, Florent Solt, CTO and chief architect of Netvibes, will discuss how the expected exponential increase in the amount of data that will be processed, transported, stored, and accessed means there will be a huge demand for smart technologies to deliver it. Florent Solt is the CTO and chief architect of Netvibes. Prior to joining Netvibes in 2007, he co-founded Rift Technol...
Join IBM June 8 at 18th Cloud Expo at the Javits Center in New York City, NY, and learn how to innovate like a startup and scale for the enterprise. You need to deliver quality applications faster and cheaper, attract and retain customers with an engaging experience across devices, and seamlessly integrate your enterprise systems. And you can't take 12 months to do it.
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, will discuss how research has demonstrated the value of Machine Learning in delivering next generation analytics to im...
This is not a small hotel event. It is also not a big vendor party where politicians and entertainers are more important than real content. This is Cloud Expo, the world's longest-running conference and exhibition focused on Cloud Computing and all that it entails. If you want serious presentations and valuable insight about Cloud Computing for three straight days, then register now for Cloud Expo.
IoT device adoption is growing at staggering rates, and with it comes opportunity for developers to meet consumer demand for an ever more connected world. Wireless communication is the key part of the encompassing components of any IoT device. Wireless connectivity enhances the device utility at the expense of ease of use and deployment challenges. Since connectivity is fundamental for IoT device development, engineers must understand how to overcome the hurdles inherent in incorporating multipl...
The paradigm has shifted. A Gartner survey shows that 43% of organizations are using or plan to implement the Internet of Things in 2016. However, not just a handful of companies are still using the old-style ad-hoc trial-and-error ways, unaware of the critical barriers, paint points, traps, and hidden roadblocks. How can you become a winner? In his session at @ThingsExpo, Tony Shan will present a methodical approach to guide the holistic adoption and enablement of IoT implementations. This ov...
The IETF draft standard for M2M certificates is a security solution specifically designed for the demanding needs of IoT/M2M applications. In his session at @ThingsExpo, Brian Romansky, VP of Strategic Technology at TrustPoint Innovation, will explain how M2M certificates can efficiently enable confidentiality, integrity, and authenticity on highly constrained devices.