Performance is a broad subject that can't be adequately covered in these chapters. There are several books available that cover various aspects of improving performance and tuning your system or network. Three useful books are:
Sun Performance and Tuning: SPARC and Solaris, by Adrian Cockcroft, SunSoft Press/PRT Prentice Hall, ISBN 0-13-149642-3
System Performance Tuning, by Mike Loukides, O'Reilly & Associates, Inc.
Managing NFS and NIS, by Hal Stern, O'Reilly & Associates, Inc.