Profile existing PL/SQL applications to identify code coverage and determine performance bottlenecks.
Subprocedures:
START_PROFILER Function
                 Start profiler data collection in the user's session. 
STOP_PROFILER Function
                 Stop profiler data collection in the user's session. 
FLUSH_DATA Function
                 Flush profiler data collected in the user's session. 
PAUSE_PROFILER Function
                 Pause profiler data collection. 
RESUME_PROFILER Function
                 Resume profiler data collection. 
GET_VERSION      Get the version of this API. 
INTERNAL_VERSION_CHECK Function
                 Verify that this version of the DBMS_PROFILER package
                 can work with the implementation in the database.  
For full documentation of the packaged procedures above see the Oracle Manual:
"Oracle9i Supplied PL/SQL Packages and Types Reference"
or the book Oracle Built in Packages by Steven Feuerstein et al
Related:
 V$Session
 V$SQL
 V$SQLAREA
 V$SQLTEXT
 V$SQLTEXT_WITH_NEWLINES
 V$SQLXS 
 V$SQL_BIND_DATA 
 V$SQL_BIND_METADATA
 V$SQL_CURSOR
 V$SQL_PLAN
 V$SQL_PLAN_STATISTICS
 V$SQL_PLAN_STATISTICS_ALL
 V$SQL_REDIRECTION
 V$SQL_SHARED_CURSOR
 V$SQL_SHARED_MEMORY
 V$SQL_WORKAREA
 V$SQL_WORKAREA_ACTIVE
 V$SQL_WORKAREA_HISTOGRAM