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Performance Monitoring: Understanding What's Happening Right Now

Insights from The Every Computer Performance Book

Performance monitoring is about understanding what's happening right now. It usually includes dealing with immediate performance problems or collecting data that will be used by the other performance tools (such as capacity planning) to plan for future peak loads.

In performance monitoring you need to know three things:

- The incoming workload

- The resulting resource consumption

- What is normal under this load

Without these three things you can only solve the most obvious performance problems and have to rely on tools outside the scientific realm (such as a Ouija Board, or a Magic 8 Ball) to predict the future.

You need to know the incoming workload (what the users are asking your system to do) because all computers run just fine under no load. Performance problems crop up as the load goes up. These performance problems come in two basic flavors: Expected and Unexpected.

Expected problems are when the users are simply asking the application for more things per second than it can do. You see this during an expected peak in demand like the biggest shopping day of the year. Expected problems are no fun, but they can be foreseen and, depending on the situation, your response might be to endure them, because money is tight or because the fix might introduce too much risk.

Unexpected problems are when the incoming workload should be well within the capabilities of the application, but something is wrong and either the end-user performance is bad or some performance meter makes no sense. Unexpected problems cause much unpleasantness and demand rapid diagnosis and repair.

Know What is Normal

The key to all performance work is to know what is normal. Let me illustrate that with a trip to the grocery store.

Image removed.

One day I was buying three potatoes and an onion for a soup I was making. The new kid behind the cash register looked at me and said: “That will be $22.50.” What surprised me was the total lack of internal error checking at this outrageous price (in 2012) for three potatoes and an onion. This could be a simple case of them not caring about doing a good job, but my more charitable assessment is that he had no idea what “normal” was, so everything the register told him had to be taken at face value. Don't be like that kid.

On any given day you, as the performance person, should be able to have a fairly good idea of how much work the users are asking the system to do and what the major performance meters are showing. If you have a good sense of what is normal for your situation, then any abnormality will jump right out at you in the same way you notice subtle changes in a loved one that a stranger would miss. This can save your bacon because if you spot the unexpected utilization before the peak occurs, then you have time to find and fix the problem before the system comes under a peak load.

There are some challenges in getting this data. For example:

- There is no workload data.

- The only workload data available (ex: per day transaction volume) is at too low a resolution to be any good for rapid performance changes.

- The workload is made of many different transaction types (buy, sell, etc.) It's not clear what to meter.

With rare exception I've found the lack of easily available workload information to be the single best predictor of how bad the overall situation is performance wise. Over the years as I visited company after company this led me to develop Bob's First Rule of Performance Work: “The less a company knows about the work their system did in the last five minutes, the more deeply screwed up they are.”

What meters should you collect? Meters fall into big categories. There are utilization meters that tell you how busy a resource is, there are count meters that count interesting events (some good, some bad), and there are duration meters that tell you how long something took. As the commemorative plate infomercial says: “Collect them all!” Please don't wait for perfection. Start somewhere, collect something and, as you explore and discover, add newly discovered meters to your collection.

When should you run the meters? Your meters should be running all the time (like bank security cameras) so that when weird things happen you have a multitude of clues to look at. You will want to search this data by time (What happened at 10:30?), so be sure to include timestamps.

The data you collect can also be used to predict the future with tools like: Capacity Planning, Load Testing, and Modeling.

This blog is based on: The Every Computer Performance Book available from Amazon and on iTunes.

ABOUT Bob Wescott

Bob Wescott is the author of The Every Computer Performance Book. Since 1987, Wescott has worked in the field of computer performance, doing professional services work and teaching how to do capacity planning, load testing, simulation modeling and web performance for Gomez/Compuware, HyPerformix/CA and Stratus Computer/Technologies. Now, Wescott is mostly retired, and his job is to give back what he has been given. His latest project is The Every Computer Performance Blog based on the book.

Related Links:

The Every Computer Performance Blog

The Every Computer Performance Book

Image removed.

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Performance Monitoring: Understanding What's Happening Right Now

Insights from The Every Computer Performance Book

Performance monitoring is about understanding what's happening right now. It usually includes dealing with immediate performance problems or collecting data that will be used by the other performance tools (such as capacity planning) to plan for future peak loads.

In performance monitoring you need to know three things:

- The incoming workload

- The resulting resource consumption

- What is normal under this load

Without these three things you can only solve the most obvious performance problems and have to rely on tools outside the scientific realm (such as a Ouija Board, or a Magic 8 Ball) to predict the future.

You need to know the incoming workload (what the users are asking your system to do) because all computers run just fine under no load. Performance problems crop up as the load goes up. These performance problems come in two basic flavors: Expected and Unexpected.

Expected problems are when the users are simply asking the application for more things per second than it can do. You see this during an expected peak in demand like the biggest shopping day of the year. Expected problems are no fun, but they can be foreseen and, depending on the situation, your response might be to endure them, because money is tight or because the fix might introduce too much risk.

Unexpected problems are when the incoming workload should be well within the capabilities of the application, but something is wrong and either the end-user performance is bad or some performance meter makes no sense. Unexpected problems cause much unpleasantness and demand rapid diagnosis and repair.

Know What is Normal

The key to all performance work is to know what is normal. Let me illustrate that with a trip to the grocery store.

Image removed.

One day I was buying three potatoes and an onion for a soup I was making. The new kid behind the cash register looked at me and said: “That will be $22.50.” What surprised me was the total lack of internal error checking at this outrageous price (in 2012) for three potatoes and an onion. This could be a simple case of them not caring about doing a good job, but my more charitable assessment is that he had no idea what “normal” was, so everything the register told him had to be taken at face value. Don't be like that kid.

On any given day you, as the performance person, should be able to have a fairly good idea of how much work the users are asking the system to do and what the major performance meters are showing. If you have a good sense of what is normal for your situation, then any abnormality will jump right out at you in the same way you notice subtle changes in a loved one that a stranger would miss. This can save your bacon because if you spot the unexpected utilization before the peak occurs, then you have time to find and fix the problem before the system comes under a peak load.

There are some challenges in getting this data. For example:

- There is no workload data.

- The only workload data available (ex: per day transaction volume) is at too low a resolution to be any good for rapid performance changes.

- The workload is made of many different transaction types (buy, sell, etc.) It's not clear what to meter.

With rare exception I've found the lack of easily available workload information to be the single best predictor of how bad the overall situation is performance wise. Over the years as I visited company after company this led me to develop Bob's First Rule of Performance Work: “The less a company knows about the work their system did in the last five minutes, the more deeply screwed up they are.”

What meters should you collect? Meters fall into big categories. There are utilization meters that tell you how busy a resource is, there are count meters that count interesting events (some good, some bad), and there are duration meters that tell you how long something took. As the commemorative plate infomercial says: “Collect them all!” Please don't wait for perfection. Start somewhere, collect something and, as you explore and discover, add newly discovered meters to your collection.

When should you run the meters? Your meters should be running all the time (like bank security cameras) so that when weird things happen you have a multitude of clues to look at. You will want to search this data by time (What happened at 10:30?), so be sure to include timestamps.

The data you collect can also be used to predict the future with tools like: Capacity Planning, Load Testing, and Modeling.

This blog is based on: The Every Computer Performance Book available from Amazon and on iTunes.

ABOUT Bob Wescott

Bob Wescott is the author of The Every Computer Performance Book. Since 1987, Wescott has worked in the field of computer performance, doing professional services work and teaching how to do capacity planning, load testing, simulation modeling and web performance for Gomez/Compuware, HyPerformix/CA and Stratus Computer/Technologies. Now, Wescott is mostly retired, and his job is to give back what he has been given. His latest project is The Every Computer Performance Blog based on the book.

Related Links:

The Every Computer Performance Blog

The Every Computer Performance Book

Image removed.

Hot Topics

The Latest

According to Auvik's 2025 IT Trends Report, 60% of IT professionals feel at least moderately burned out on the job, with 43% stating that their workload is contributing to work stress. At the same time, many IT professionals are naming AI and machine learning as key areas they'd most like to upskill ...

Businesses that face downtime or outages risk financial and reputational damage, as well as reducing partner, shareholder, and customer trust. One of the major challenges that enterprises face is implementing a robust business continuity plan. What's the solution? The answer may lie in disaster recovery tactics such as truly immutable storage and regular disaster recovery testing ...

IT spending is expected to jump nearly 10% in 2025, and organizations are now facing pressure to manage costs without slowing down critical functions like observability. To meet the challenge, leaders are turning to smarter, more cost effective business strategies. Enter stage right: OpenTelemetry, the missing piece of the puzzle that is no longer just an option but rather a strategic advantage ...

Amidst the threat of cyberhacks and data breaches, companies install several security measures to keep their business safely afloat. These measures aim to protect businesses, employees, and crucial data. Yet, employees perceive them as burdensome. Frustrated with complex logins, slow access, and constant security checks, workers decide to completely bypass all security set-ups ...

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Cloudbrink's Personal SASE services provide last-mile acceleration and reduction in latency

In MEAN TIME TO INSIGHT Episode 13, Shamus McGillicuddy, VP of Research, Network Infrastructure and Operations, at EMA discusses hybrid multi-cloud networking strategy ... 

In high-traffic environments, the sheer volume and unpredictable nature of network incidents can quickly overwhelm even the most skilled teams, hindering their ability to react swiftly and effectively, potentially impacting service availability and overall business performance. This is where closed-loop remediation comes into the picture: an IT management concept designed to address the escalating complexity of modern networks ...

In 2025, enterprise workflows are undergoing a seismic shift. Propelled by breakthroughs in generative AI (GenAI), large language models (LLMs), and natural language processing (NLP), a new paradigm is emerging — agentic AI. This technology is not just automating tasks; it's reimagining how organizations make decisions, engage customers, and operate at scale ...

In the early days of the cloud revolution, business leaders perceived cloud services as a means of sidelining IT organizations. IT was too slow, too expensive, or incapable of supporting new technologies. With a team of developers, line of business managers could deploy new applications and services in the cloud. IT has been fighting to retake control ever since. Today, IT is back in the driver's seat, according to new research by Enterprise Management Associates (EMA) ...

In today's fast-paced and increasingly complex network environments, Network Operations Centers (NOCs) are the backbone of ensuring continuous uptime, smooth service delivery, and rapid issue resolution. However, the challenges faced by NOC teams are only growing. In a recent study, 78% state network complexity has grown significantly over the last few years while 84% regularly learn about network issues from users. It is imperative we adopt a new approach to managing today's network experiences ...

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