QPS drops by 11% for one point-query test from sysbench

The relative QPS for the points-covered-si test that I run via sysbench drops by about 20% starting in 11.0.6, it then improved a bit in 11.8.3 and the QPS in 12.1.1 is about 11% less than 10.2.30 (rQPS was 1.05 in 10.11.14, drops to 0.83 in 11.0.6, rises to 0.91 in 11.8.3 and is now 0.89 in 12.1.1 – relative QPS is (QPS for my version / QPS for 10.2.30). The numbers are here.

A repro script that runs all tests, including points-covered-si, is here. I ran it with 40 clients, 8 tables and 10M rows per table on a 48-core server.

From vmstat metrics the CPU overhead increases by about 1.27X in 11.0.6. I don't see an increase in context switches. See cpu/o here