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Debugging Performance Issues

 

This section describes the three common bounding scenarios of a live SBRC system, which can be verified using the tools listed in Table 15. They are:

Focus is primarily on Solaris tools, but the techniques of analysis apply to Linux as well.

CPU Bound

CPU Bound

This section shows output in which the SBRC is well utilizing the available CPU and the CPU utilization is spread over many threads (see Figure 7).

Note

The peak utilization rate is not much higher than the current rate.

Figure 7: CPU-Bound Utilization
CPU-Bound Utilization

prstat output

The following output shows no significant I/O usage:

I/O Bound

I/O Bound

Figure 8 shows output of a system that is more I/O bound (large packets being written to a long accounting file with LogAccept=1, LogLevel=2, TraceLevel=2). In this case, the CPU overhead of I/O is very high, and larger multiprocessor systems with more optimized I/O frameworks (such as Fibre Channel NASD devices and RAIDs) will see higher rates and lower CPU utilization if they are I/O bound.

Figure 8: I/O-Bound Utilization
I/O-Bound Utilization

Contended Systems

Contended Systems

Figure 9 is an example of a contended system with many (artificially induced) errors.

Figure 9: Contended Systems Utilization
Contended Systems Utilization