Welcome!

@DevOpsSummit Authors: Pat Romanski, Elizabeth White, Toddy Mladenov, Jyoti Bansal, Dana Gardner

Related Topics: @DevOpsSummit, Java IoT, Linux Containers

@DevOpsSummit: Blog Feed Post

Getting Real About Memory Leaks | @DevOpsSummit #APM #DevOps #ContinuousTesting

Modern programming languages tend to separate the programmer from memory management

Getting Real About Memory Leaks
By Matt Heusser

Modern programming languages tend to separate the programmer from memory management; Java programmers don't have to deal with pointers; they just declare variables and let the built-in garbage collector do its thing.

These garbage collectors are smart, but not perfect; they typically work by object reference. When all the references to an object go out of memory, that object can go out of memory too. Yet if two objects point to each other, they will always have a reference count, and never go away. That means the code written in Javascript to run in a browser, or Objective-C to run on a hand-held phone, or ASP to run on a server could very well have a memory leak.

When memory leaks happen on modern Operating Systems, the Operating System isn't going to throw an error. Instead, it will just use more and more memory, eventually going to virtual memory on the disk. When that happens, performance falls apart. People in operations reboot the server and that "seems to fix it"; users close and restart their browser, or reboot their phone.

Consider the Following Example
My first job in software was to create an electronic audit of a telecommunications bill. Some other software, maintained by my coworker Jeff, would read accounts, phones, and calls from a database and then create a text file that could be interpreted by a printer, called a post-script file. If we were smart, we'd have had written the tool in two parts, first to create a bunch of excel-like text files, then a second piece to combine those into bills.

One day, about four months in, the President of our 30-person software company came downstairs to my desk and said "Matt, I want you to take over the telecom bills", doing maintenance and new feature development.

The program was written in C. It read a list of accounts and looped through every account. Not every active account, every account, because an inactive account could still have an unpaid balance. We calculated the balance by adding up all the debits and credits through all time. If that amount added up to zero, we could skip the account. That was no big deal when we were helping a new, competitive regional carrier get started, with forty or fifty accounts and billing for five or six months.

The competitive carrier, however, was good at, well, competing. By the time I took over they had eighteen hundred accounts, and would be in the tens of thousands (and three states) before I left. Performance would become a real problem, but not for the reasons I expected.

The first two problems that hit us were a pointer out of range, then a memory leak.

Memory Out of Bounds
The software needed to store a great deal of data in memory for each account (the buildings, phones, calls, costs, and taxes) then spit it out to disk in post-script format. There are two basic ways to do this in C: Either allocate memory with pointers, which is hard to track, or simulate it using arrays. We didn't have objects, Test Driven Development wasn't really a thing, and I was inheriting code designed to support a very small customer base. What we did have was arrays. So to support two thousand calls, we could do something like this:

struct call {

char inOrOutbound;

datetimestamp timeStart;

datetimestamp timeEnd;

integer billedMinutes;

double cost;

}

char buildings  [200][200];

char phones [200][200][1000][1000];

call calls [200][200][1000][1000];

What's represented here is up to 200 buildings per account, each of which can have 200 phones, each of which can have up to 1000 calls. The variable calls [5][10][25] would contain the fifth call for the tenth phone at the twenty fifth building. Actually, since C is zero-based, it would be the 6th call at the third phone at the eleventh building.

The software was basically a loop. For each account, for each building, for each phone, for each call. The calls needed to be sorted, then the results printed. Everything worked fine until in one run I got a memory out of bounds error. That's probably because the code was trying to access building 201, phone 201, or call 1001. The compiler has range checking built-in by default. To get around this, I moved the size of the data structure up as large as possible, which worked until we got an account that was too big for that.

Then I turned off range checking and declared a large amount of empty data structures, matching the originals in type, below the originals. That is an incredibly foolish thing to do, but it worked. Because the data structures were built into the compiled program (the ".exe file") and would be re-used for every account. Our little program would declare all the memory it needed one time, at the beginning, and use that.

Until we found the system slowing to a crawl on big accounts, like it was choking.

Enter The Memory Leaks
The data structures above are an over-simplification. We also needed to store the addresses of the building, the payments since the last bill, and so on. Like the examples above some of these were declared variables, put in the compiled code, "on the stack". Others were grabbed at run-time, using a C program call named "malloc" and its friend "free." Instead of declaring an array, we'd declare a character pointer, then malloc() some space at that pointer. When the function was done, we could free() the disk space.

If we remembered to do that.

As you've probably guessed, we had too many calls to malloc() and not enough to free(). That meant that memory use slowly crept up as we used the software. That's fine for fifty or even five hundred accounts; the memory use would go away when the program finished running. But, we started to get some very big accounts. I noticed that one big account would run, and performance would go down. The kicker, for me, was an out of memory error for our user. I went to Rich, the sysadmin, and asked for more memory for the user. He suggested I tune it instead. After carefully poring over the code, I found some mallocs() that weren't being freed. Adding the calls to free, the program did eventually finish. That account still took too long, but that's enough for today.

You might see how I struggled, but you might not see what that has to do with modern software delivery. Allow me to share just a bit more.

The Lesson for Today
These problems are silent killers, and fixing them is no longer as easy as searching through a program making sure every malloc() has a matching free().

If you write embedded medical software, or avionics, or anything in C, you are probably very familiar with these problems. If you don't, you might not be, but the problems are still there.

If your application degrades over time, the problem might just be memory leaks. The next logical question is how to find them.

Read the original blog entry...

More Stories By SmartBear Blog

As the leader in software quality tools for the connected world, SmartBear supports more than two million software professionals and over 25,000 organizations in 90 countries that use its products to build and deliver the world’s greatest applications. With today’s applications deploying on mobile, Web, desktop, Internet of Things (IoT) or even embedded computing platforms, the connected nature of these applications through public and private APIs presents a unique set of challenges for developers, testers and operations teams. SmartBear's software quality tools assist with code review, functional and load testing, API readiness as well as performance monitoring of these modern applications.

@DevOpsSummit Stories
For organizations that have amassed large sums of software complexity, taking a microservices approach is the first step toward DevOps and continuous improvement / development. Integrating system-level analysis with microservices makes it easier to change and add functionality to applications at any time without the increase of risk. Before you start big transformation projects or a cloud migration, make sure these changes won’t take down your entire organization.
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From planning to development to management to security, CA creates software that fuels transformation for companies in the application economy.
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @DevOpsSummit 19th Cloud Expo, moderated by DevOps Conference Chair Andi Mann, panelists will explore this emerging use of Big Data generated by the digital business to complete the DevOps feedback loop, and inform operational and application decisions.
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you can concentrate on running a better service for your users.
Cloud Expo, Inc. has announced today that Andi Mann and Aruna Ravichandran have been named Co-Chairs of @DevOpsSummit at Cloud Expo 2017. The @DevOpsSummit at Cloud Expo New York will take place on June 6-8, 2017, at the Javits Center in New York City, New York, and @DevOpsSummit at Cloud Expo Silicon Valley will take place Oct. 31-Nov. 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Cloud Academy will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud computing technologies. Get certified, manage the full lifecycle of your cloud-based resources, and build your knowledge based using Cloud Academy’s expert-created content, comprehensive Learning Paths, and innovative Hands-on Labs.
With 10 simultaneous tracks, keynotes, general sessions and targeted breakout classes, Cloud Expo and @ThingsExpo are two of the most important technology events of the year. Since its launch over eight years ago, Cloud Expo and @ThingsExpo have presented a rock star faculty as well as showcased hundreds of sponsors and exhibitors! In this blog post, I provide 7 tips on how, as part of our world-class faculty, you can deliver one of the most popular sessions at our events. But before reading these essential tips, please take a moment and watch this brief video from Sandy Carter.
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain.
In his general session at 18th Cloud Expo, Lee Atchison, Principal Cloud Architect and Advocate at New Relic, discussed cloud as a ‘better data center’ and how it adds new capacity (faster) and improves application availability (redundancy). The cloud is a ‘Dynamic Tool for Dynamic Apps’ and resource allocation is an integral part of your application architecture, so use only the resources you need and allocate /de-allocate resources on the fly.
TechTarget storage websites are the best online information resource for news, tips and expert advice for the storage, backup and disaster recovery markets. By creating abundant, high-quality editorial content across more than 140 highly targeted technology-specific websites, TechTarget attracts and nurtures communities of technology buyers researching their companies' information technology needs. By understanding these buyers' content consumption behaviors, TechTarget creates the purchase intent insights that fuel efficient and effective marketing and sales activities for clients around the world.
Column Technologies exhibited at SYS-CON's @DevOpsSummit at Cloud Expo, which took place at the Javits Center in New York City, NY, in June 2016. Established in 1998, Column Technologies is a global technology solutions provider with over 400 employees, headquartered in the United States with offices in Canada, India, and the United Kingdom. Column Technologies provides “Best of Breed” technology solutions that automate the key DevOps principals and help our customers meet today’s DevOps and Digital Transformation challenges.
Your homes and cars can be automated and self-serviced. Why can't your storage? From simply asking questions to analyze and troubleshoot your infrastructure, to provisioning storage with snapshots, recovery and replication, your wildest sci-fi dream has come true. In his session at @DevOpsSummit at 20th Cloud Expo, Dan Florea, Director of Product Management at Tintri, will provide a ChatOps demo where you can talk to your storage and manage it from anywhere, through Slack and similar services with Tintri's web services architecture and APIs. Impress your DevOps team with smart and autonomous infrastructure.
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Have you ever noticed how some IT people seem to lead successful, rewarding, and satisfying lives and careers, while others struggle? IT author and speaker Don Crawley uncovered the five principles that successful IT people use to build satisfying lives and careers and he shares them in this fast-paced, thought-provoking webinar. You'll learn the importance of striking a balance with technical skills and people skills, challenge your pre-existing ideas about IT customer service, and gain new insights into how to build your own satisfying and rewarding career by rising above the ordinary and mundane to build an extraordinary life and career as a world-class Compassionate Geek.
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
@DevOpsSummit at Cloud taking place June 6-8, 2017, at Javits Center, New York City, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.
In his keynote at 19th Cloud Expo, Sheng Liang, co-founder and CEO of Rancher Labs, discussed the technological advances and new business opportunities created by the rapid adoption of containers. With the success of Amazon Web Services (AWS) and various open source technologies used to build private clouds, cloud computing has become an essential component of IT strategy. However, users continue to face challenges in implementing clouds, as older technologies evolve and newer ones like Docker containers gain prominence. He explored these challenges and how to address them, while considering how containers will influence the direction of cloud computing.
DevOps and microservices are permeating software engineering teams broadly, whether these teams are in pure software shops but happen to run a business, such Uber and Airbnb, or in companies that rely heavily on software to run more traditional business, such as financial firms or high-end manufacturers. Microservices and DevOps have created software development and therefore business speed and agility benefits, but they have also created problems; specifically, they have created software security issues.
All clouds are not equal. To succeed in a DevOps context, organizations should plan to develop/deploy apps across a choice of on-premise and public clouds simultaneously depending on the business needs. This is where the concept of the Lean Cloud comes in - resting on the idea that you often need to relocate your app modules over their life cycles for both innovation and operational efficiency in the cloud. In his session at @DevOpsSummit at19th Cloud Expo, Valentin (Val) Bercovici, CTO of SolidFire, discussed how to leverage this concept to seize on the creativity and business agility to make it real.
Cloud Expo, Inc. has announced today that Aruna Ravichandran, vice president of DevOps Product and Solutions Marketing at CA Technologies, has been named co-conference chair of DevOps at Cloud Expo 2017. The @DevOpsSummit at Cloud Expo New York will take place on June 6-8, 2017, at the Javits Center in New York City, New York, and @DevOpsSummit at Cloud Expo Silicon Valley will take place Oct. 31-Nov. 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Tricky charts and visually deceptive graphs often make a case for the impact IT performance has on business. The debate isn't around the obvious; of course, IT performance metrics like website load time influence business metrics such as conversions and revenue. Rather, this presentation will explore various data analysis concepts to understand how, and how not to, assert such correlations. In his session at 20th Cloud Expo, Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, will review data analysis basics, and then move into some data-to-actionable information concepts. Afterward, YOU decide whether to use your newfound knowledge for good or evil.
@DevOpsSummit has been named the ‘Top DevOps Influencer' by iTrend. iTrend processes millions of conversations, tweets, interactions, news articles, press releases, blog posts - and extract meaning form them and analyzes mobile and desktop software platforms used to communicate, various metadata (such as geo location), and automation tools. In overall placement, @DevOpsSummit ranked as the number one ‘DevOps Influencer' followed by @CloudExpo at third, and @MicroservicesE at 24th.
To manage complex web services with lots of calls to the cloud, many businesses have invested in Application Performance Management (APM) and Network Performance Management (NPM) tools. Together APM and NPM tools are essential aids in improving a business's infrastructure required to support an effective web experience... but they are missing a critical component - Internet visibility.
Microservices are a very exciting architectural approach that many organizations are looking to as a way to accelerate innovation. Microservices promise to allow teams to move away from monolithic "ball of mud" systems, but the reality is that, in the vast majority of organizations, different projects and technologies will continue to be developed at different speeds. How to handle the dependencies between these disparate systems with different iteration cycles? Consider the "canoncial problem" in this scenario: microservice A (releases daily) depends on a couple of additions to backend B (releases quarterly).