db and application slow for 15mints when log switch

Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            Buffer Nowait %:   99.96       Redo NoWait %:   99.84
            Buffer  Hit   %:   99.52    In-memory Sort %:  100.00
            Library Hit   %:   98.94        Soft Parse %:   96.66
         Execute to Parse %:   70.95         Latch Hit %:   99.94
Parse CPU to Parse Elapsd %:    0.00     % Non-Parse CPU:   90.75

 Shared Pool Statistics        Begin    End
                              ------  ------
             Memory Usage %:   77.83   77.03
    % SQL with executions>1:   92.16   90.53
  % Memory for SQL w/exec>1:   91.56   91.77

Top 5 Timed Foreground Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                                           Avg
                                                          wait   % DB
Event                                 Waits     Time(s)   (ms)   time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
log file sync                         2,465       4,898   1987   38.9 Commit
buffer busy waits                     5,387       4,200    780   33.3 Concurrenc
log file switch (private stran        3,797       3,118    821   24.8 Configurat
log buffer space                        270         248    917    2.0 Configurat
DB CPU                                               40            .3
^LHost CPU (CPUs:   16 Cores:    8 Sockets:    2)
~~~~~~~~         Load Average
               Begin       End     %User   %System      %WIO     %Idle
           --------- --------- --------- --------- --------- ---------