Solaris comes with a wonderful tool Dtrace, you will find on this website Dtrace scripts at OpenSolaris some real world usefull tool.

Example with iosnoop

 UID   PID D    BLOCK   SIZE       COMM PATHNAME
1017 15596 R  3106752   8192        php /lib/libsocket.so.1
1017 15596 R 16045424   8192        php /opt/monitor/libxml2-2.6.23/lib/libxml2.so.2.6.23
1001 23079 W    37229  45568       java <none>
1017 15596 R  5702384   8192        php /usr/sfw/lib/libexpat.so.0.5.0
1017 15584 W  2373790   1024        php /var/net-snmp/snmpapp.conf

A great book regarding dtrace and performance Solaris Performance and Tools, Prentice Hall and the Wiki Solaris performance