PureFTPd "-m" flag CPU load measured in??

[michaelsanford]

The readme simply says

-m: <cpu load> Don't allow anonymous downlaod if the load is above <cpu load>. A very efficient way to prevent overloading your server...

Is this a percentage load, or one of those obscure load numbers reported by uptime? And does anyone know what happens if the load is exceeded (what does the user see?)

Thanks!