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Optimizing Linux® Performance: A Hands-On Guide to Linux® Performance ToolsBy
Table of Contents
| Index
The first comprehensive, expert guide for end-to-end Linux
application optimization
Learn to choose the right toolsand use them together to
solve real problems in real production environmentsSuperior application performance is more crucial than
everand in today''s complex production environments, it''s
tougher to ensure, too. If you use Linux, you have extraordinary
advantages: complete source code access, plus an exceptional array
of optimization tools. But the tools are scattered across the
Internet. Many are poorly documented. And few experts know how to
use them together to solve real problems. Now, one of those experts
has written the definitive Linux tuning primer for every
professional: Optimizing Linux® Performance.Renowned Linux benchmarking specialist Phillip Ezolt introduces
each of today''s most important Linux optimization tools, showing
how they fit into a proven methodology for perfecting overall
application performance. Using realistic examples, Ezolt shows
developers how to pinpoint exact lines of source code that are
impacting performance. He teaches sysadmins and application
developers how to rapidly drill down to specific bottlenecks, so
they can implement solutions more quickly. You''ll discover how
to:
Identify bottlenecks even if you''re not familiar with the
underlying system
Find and choose the right performance tools for any
problem
Recognize the meaning of the events you''re measuring
Optimize system CPU, user CPU, memory, network I/O, and disk
I/Oand understand their interrelationships
Fix CPU-bound, latency-sensitive, and I/O-bound applications,
through case studies you can easily adapt to your own
environmentInstall and use oprofile, the advanced systemwide profiler for
Linux systemsIf you''re new to tuning, Ezolt gives you a clear and practical
introduction to all the principles and strategies you''ll need. If
you''re migrating to Linux, you''ll quickly master Linux equivalents
to the tools and techniques you already know. Whatever your
background or environment, this book can help you improve the
performance of all your Linux applicationsincreasing
business value and user satisfaction at the same time.
9.8. Optimizing Network I/O Usage
When you know that a network problem is happening, Linux provides a set of tools to determine which applications are involved. However, when you are connected to external machines, the fix to a network problem is not always within your control.Figure 9-6 shows the steps that we take to investigate a network performance problem.
Figure 9-6.
9.8.1. Is Any Network Device Sending/Receiving Near the Theoretical Limit?
The first thing to do is to use ethtool to determine what hardware speed each Ethernet device is set to. If you record this information, you then investigate whether any of the network devices are saturated. Ethernet devices and/or switches can be easily mis-configured, and ethtool shows what speed each device believes that it is operating at. After you determine the theoretical limit of each of the Ethernet devices, use iptraf (of even ifconfig) to determine the amount of traffic that is flowing over each interface. If any of the network devices appear to be saturated, go to Section 9.8.3; otherwise, go to Section 9.8.2.
9.8.2. Is Any Network Device Generating a Large Number of Errors?
Network traffic can Section 9.9.
9.8.3. What Type of Traffic Is Running on That Device?
If a particular device is servicing a large amount of data, use iptraf to track down what types of traffic that device is sending and receiving. When you know the type of traffic that the device is handling, advance to Section 9.8.4.
9.8.4. Is a Particular Process Responsible for That Traffic?
Next, we want to determine whether a particular process is responsible for that traffic. Use netstat with the -p switch to see whether any process is handling the type of traffic that is flowing over the network port.If an application is responsible, go to Section 9.8.6. If none are responsible, go to Section 9.8.5.
9.8.5. What Remote System Is Sending the Traffic?
If no application is responsible Section 9.9.
9.8.6. Which Application Socket Is Responsible for the Traffic?
Determining Section 9.9.
