Figure 4-24 shows that since the system was last rebooted, no network packets have been dropped. That's what I like to see!

Operating system bottleneck analysis can be extremely satisfying and useful. Coming from an Oracle DBA, this may sound strange. But understanding what's happening to the operating system not only strengthens my performance analysis, but also gives me a much deeper knowledge of computing systems.

Here, you've seen that a CPU subsystem has only one run queue and why an IO subsystem without a massive cache will immediately queue transactions. I've shown you how to confirm an IO bottleneck using multiple techniques and how to maximize either response time or throughput by controlling the workload.