How to genrate awr report

1) Connect with sys user 

$ sqlplus / as sysdba

2) Run script awrrpt which you can find in ORACLE_HOME/rdbms/admin folder

SQL> @$ORACLE_HOME/rdbms/admin/awrrpt


3) Specify the name of report type

Enter value for report_type: html

4) Specify the number of  days you want to interested the awr report

Enter value for num_days: 1

5)  Now you will found the list of 

Listing the last day's Completed Snapshots  Snap Id  per hour from where you can choose the sanp Id of specific interval of time

Snap
Instance DB Name Snap Id Snap Started Level
------------ ------------ --------- ------------------ -----
orcl orcl 16159 18 May 2012 00:00 1
16160 18 May 2012 01:00 1
16161 18 May 2012 02:00 1
16162 18 May 2012 03:00 1
16163 18 May 2012 04:00 1
16164 18 May 2012 05:00 1



6) Mention  start time or end time :

Specify the Begin and End Snapshot Ids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Enter value for begin_snap: 16159
Begin Snapshot Id specified: 16159

Enter value for end_snap: 16162
End Snapshot Id specified: 16162

7)  Specify the Report Name 

Specify the Report Name
~~~~~~~~~~~~~~~~~~~~~~~
The default report file name is awrrpt_1.html. To use this name,
press <return> to continue, otherwise enter an alternative.