Doing a Compilation from Source is cumbersome. If you just follow the most prominent link from google, you will get an outdated version. So go to http://sourceforge.net/projects/xosview/, chose "Download|Browse all files" and select the latest stable version. Download and compile it as described under Compilation.
If you get an error like this:
In file included from /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../../../include/c++/3.4.6/backward/iostream.h:31, from /root/xosview-1.8.0/xwin.h:12, from /root/xosview-1.8.0/xosview.h:14, from /root/xosview-1.8.0/meter.h:15, from /root/xosview-1.8.0/fieldmetergraph.h:17, from cpumeter.h:12, from cpumeter.cc:9: /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../../../include/c++/3.4.6/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 18.104.22.168 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated. cpumeter.cc:14:23: strstream.h: No such file or directory
You are probably trying to compile xosview 1.8.0 which is not the latest stable version. Upgrading to 1.8.3 helps.
If you have 16 processors or more, xosview's display can become very slow. Maybe you only want the network load and not the CPU load, then call it like this:
xosview -cpu +net