Performance of XtraDB slows down significantly on long benchmarks

I have run 6h tests using both Percona Server 5.6.16-64 as MariaDB 10.0.9 using XtraDB 5.6.15-63.0. Benchmark used is Linkbench using 10x database, i.e. maxid = 100000001 and database is ~100G. Buffer pool used is 50G. I will attach results from LinkBench measure phase where the performance decrease is evident. Using ROW_FORMAT=compressed this decracation if severe and using uncompressed tables not so significant but clear. I have run compressed also using MariaDB 10.0.9 using Oracle InnoDB and there I can't see similar performance decrease.

Percona Server 5.6.16-64 and ROW_FORMAT=COMPRESSED using linkbench with 10x database and 6h time limit. Similar run with MariaDB 10.0.10 (unofficial). End results:

Percona: 1998 ops/sec
MariaDB: 21074 ops/sec