Different numbers of iterations while running code in different hardware paltform

I ran AMG on Xeon, KNL and KNM platform, but when I was running on KNM/KNL I find that the numbers of iterations become much more than on Xeon(with same configuration), what's more, when I running with 1 OMP thread per process, the number of iterations will become 0 on KNM/KNL, is there any way(like some flag) to control the number of iteration, or this is a problem of the code?

The issue names no source files, tests, or entry points. Start by reproducing AMG with the same configuration on Xeon, KNL, and KNM, including one OMP thread per process, then inspect the available iteration controls and platform-specific runtime output. Done means determining whether the iteration difference or zero count is expected behavior or a reproducible code defect, with the command and evidence recorded.

Written by the indexing model from the issue text.