The hwlat_detector module can to detect hardware latencies caused by System Management Interrupt (SMI). SMI is a BIOS features which interrupts any running software (including the kernel) the execute hardware protective routines (for example hw ECC corrections, increasing CPU temperature, etc). Unfortunate SMI routine could be programmed, then some virus can use it to stay running even when you reinstall your computer operating system.
In fact this is not the only SMI drawback, because it interrupts the running software (kernel) it make difficult to use common PC to real time tasks.
To detect this kind of latencies Jon Master developed a module to detect it: