Comment 4 for bug 1631309

This has indeed been found in MariaDB first. But I verified the regression in Percona Server (in order to make sure this came from XtraDB upstream). As a matter of fact the regression is heavier in Percona Server (95%) as in MariaDB (90%). This might indeed be caused by different defaults, however not innodb_lru_scan_depth. It's set to 1024 in both MariaDB and Percona Server.

The numbers I quoted above are for Percona Server, built from source tarballs and with nothing in my.cnf except socket and datadir location.

Rolling back the said commit restores performance in both cases.