LP:955776 - 5.2 vs 5.3 CPU usage. Is it normal?

Hello there

Yesterday we tried to migrate from MariaDB 5.2 to 5.3 on one of our servers. We have noticed very huge growth of CPU usage by mysqld processes. The following are 2 pictures showing what happened. Upgrade has been done at about 22:00, used default optimizer_switch settings.

http://clip2net.com/clip/m115425/1331798690-dbprousercpu1-22kb.png
http://clip2net.com/clip/m115425/1331798721-dbprousercpu2-22kb.png

After changing optimizer_switch to index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=off,semijoin=off,partial_match_rowid_merge=off,partial_match_table_scan=off,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=off,join_cache_hashed=off,join_cache_bka=off,optimize_join_buffer_size=off,table_elimination=off (similar to 5.2 values) in some cases CPU usage decreases but not always.