[ziofill]

> Two cores are disabled per cluster.

I’m sure there is a good reason for this, which is..?

[jandrewrogers]

It is likely that those cores are dedicated to unrelated management, monitoring, and administrative tasks. This is common and many workloads are throttled on bandwidth anyway. For the purposes of the benchmark, those cores are not participating in the workload.

[brianolson]

Yield. Some fraction of cores had a speck of dust or something, but at 38/40 good cores per chip they got economical yield

[tjhei]

And then even if some nodes had 40/40 "good" cores, it would make load balancing a lot more complicated if core counts vary. Easier to turn them off at the hardware level.

[dist-epoch]

Couldn't some chips have 40 good cores, while others have only 36? Do they all need to be exactly 38?