fi_cntr_set(3) on Linux
The text de89242ae115, as Debian 10 (Buster) shipped it.
Completion and event counter operations fi_cntr_open / fi_close : Allocate/free a counter fi_cntr_read : Read the current value of a counter fi_cntr_readerr : Reads the number of operations which have completed in error. fi_cntr_add : Increment a counter by a specified value fi_cntr_set : Set a counter to a specified value fi_cntr_wait : Wait for a counter to be greater or equal to a threshold value