Java programmers will want to read this book. It is sponsored by Oracle, so it explains verbosely why the SPARC T series processors are preferred for highly parallel workloads, though the IA86 processors show better performance with less parallel test cases.
Java has evolved. For example, if you are using the traditional Hashtable to synchronize threads then this book will show why you need to be using ConcurrentHashMap to avoid blocking.
The book is useful, but I wish it had been edited by someone at O’Reilly.