The profile utility can set the sprofiling mode

- profile --nmi | --rtc sets the profiling mode

- --rtc is default, uses BIOS RTC, cannot profile kernel the presetted
  frequency values apply

- --nmi is only available in APIC mode as it uses the NMI watchdog, -f
  allows any frequency in Hz

- both modes use compatible data structures

lib/libc/other/_sprofile.c

@@ -2,13 +2,19 @@
 
 #define sprofile _sprofile
 
-PUBLIC int sprofile(int action, int size, int freq, char *ctl_ptr, int *mem_ptr)
+PUBLIC int sprofile(int action,
+		int size,
+		int freq,
+		int type,
+		char *ctl_ptr,
+		int *mem_ptr)
 {
   message m;
 
   m.PROF_ACTION         = action;
   m.PROF_MEM_SIZE       = size;
   m.PROF_FREQ           = freq;
+  m.PROF_INTR_TYPE      = type;
   m.PROF_CTL_PTR        = (void *) ctl_ptr;
   m.PROF_MEM_PTR        = (void *) mem_ptr;