This is rather interesting. Since Christoph refuses to, here's my
results with 8f40f67, first with slab:
Now, change the config to slub:
and we get slightly better results:
willy@piggy:~$ sudo ./io-gen -d /dev/sda -j4
CPU 0 completed 1000000 ops in 45.848 seconds; 21811 ops per second
CPU 2 completed 1000000 ops in 50.789 seconds; 19689 ops per second
CPU 3 completed 1000000 ops in 55.876 seconds; 17896 ops per second
CPU 1 completed 1000000 ops in 56.941 seconds; 17562 ops per second
willy@piggy:~$ sudo taskset -p 1 1001
pid 1001's current affinity mask: f
pid 1001's new affinity mask: 1
willy@piggy:~$ sudo ./io-gen -d /dev/sda -j4
CPU 2 completed 1000000 ops in 45.713 seconds; 21875 ops per second
CPU 0 completed 1000000 ops in 47.020 seconds; 21267 ops per second
CPU 3 completed 1000000 ops in 58.692 seconds; 17038 ops per second
CPU 1 completed 1000000 ops in 60.389 seconds; 16559 ops per second