[openmp] [runtime] Use getloadavg() on NetBSD as well

[mgorny]

Summary

Switch NetBSD from reading /proc (which is broken) to getloadavg()
(which is already used by Darwin). NetBSD discourages using procfs
in favor of system API calls.

[mgorny]

runtime/src/z_Linux_util.cpp

2088 ↗

(On Diff #177408)

BTW this one doesn't seem to be used either. If you agree, I can send a separate change removing it as well.

[krytarowski]

The official core statement in NetBSD is to deprecate /proc. Can we switch to share code with KMP_OS_DARWIN? Are there any issues with it?

If there is need to count running threads, we shall use sysctl(3) to get the list of threads.

[krytarowski]

If there are any issues with getloadavg(3), I will prepare a sysctl(3)-based function.

[krytarowski]

I would leave intact the Linux code as it's used for sanity check.

[mgorny]

@krytarowski, updated as requested. FTR, this branch is using different rules for load-balancing apparently.

openmp/trunk/runtime/src/z_Linux_util.cpp

 #endif
 
   return found;
 
 } // __kmp_is_address_mapped
 
 #ifdef USE_LOAD_BALANCE
 
-#if KMP_OS_DARWIN
+#if KMP_OS_DARWIN || KMP_OS_NETBSD
 
 // The function returns the rounded value of the system load average
 // during given time interval which depends on the value of
 // __kmp_load_balance_interval variable (default is 60 sec, other values
 // may be 300 sec or 900 sec).
 // It returns -1 in case of error.
 int __kmp_get_load_balance(int max) {
   double averages[3];