11gR2 : QUERY Parallelism and AWR

Hi ,

Could you please help me to analyze  “AWR” attached file following the parallel execution (DOP  11g) of a series of queries in a batch :performance improvements  < 3% !!! 

Here various parameters of parallelization used in my  context.

Thanks for your help .

GD.

AIX server : 10 CPU and 20Go of RAM.

cpu_count                            integer     10
parallel_threads_per_cpu             integer     2

DATABASE   : 11.2.0.3

SQL> show parameter parallel
 
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
fast_start_parallel_rollback         string      LOW
parallel_adaptive_multi_user         boolean     TRUE
parallel_automatic_tuning            boolean     FALSE
parallel_degree_limit                string      CPU
parallel_degree_policy               string      MANUAL
parallel_execution_message_size      integer     16384
parallel_force_local                 boolean     FALSE