cpucount.functions

# This file is part of shellfire cpucount. It is subject to the licence terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/shellfire-dev/cpucount/master/COPYRIGHT. No part of shellfire cpucount, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file.
# Copyright © 2014-2015 The developers of shellfire cpucount. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/shellfire-dev/cpucount/master/COPYRIGHT.


# Finds number of hyperthreaded CPUs (ie double number of CPUs) - ignores cpuset, etc
core_dependency_requires '*' grep uname
# core_dependency_requires macosx
cpucount_findNumberOfHyperthreadedCpus()
{
	# Windows, eg Msys
	if core_variable_isSet NUMBER_OF_PROCESSORS; then
	
		case "$NUMBER_OF_PROCESSORS" in
		    ''|*[!0-9]*)
				:
			;;
		
		    *)
				printf '%s' "$NUMBER_OF_PROCESSORS"
				return 9
			;;
		esac
		
	fi
	
	# Should work under Linux and Cygwin
	if [ -f /proc/cpuinfo ]; then
		grep -E -c '^processor[[:space:]]*:[[:space:]]' /proc/cpuinfo
		return 0
	fi
	
	local os="$(uname)"
	case "$os" in
		
		Darwin)
	 		# machdep.cpu.core_count is number of CPUs
	 		# In practice, all modern Macs are hyperthreaded
			sysctl -n machdep.cpu.thread_count
		;;
		
		FreeBSD)
			sysctl -n hw.ncpu
		;;
		
		*)
			core_message NOTICE "Could not determine hyperthreaded CPU count for your operating system '$os'"
		;;
		
	esac
}

cpucount_computeMakeJobsAndLoadAverage()
{
	# converts strings to 0, ie 'max' goes to 0
	local configuredCpuCount=$1
	local configuredLoadAverageCorrection=$2
	local cpucount_discoveredNumberOfCpus="$(cpucount_findNumberOfHyperthreadedCpus)"
	
	if [ $configuredCpuCount -eq 0 ]; then
		cpucount_makeJobs=$cpucount_discoveredNumberOfCpus
	elif [ $configuredCpuCount -lt 0 ]; then
		# reduce number of cpus
		local -i potentialCpus=$((cpucount_discoveredNumberOfCpus + configuredCpuCount))
		if [ $potentialCpus -lt 1 ]; then
			cpucount_makeJobs=1
		else
			cpucount_makeJobs=$potentialCpus
		fi
	else
		cpucount_makeJobs=$cpucount_discoveredNumberOfCpus
	fi
	
	if [ $configuredLoadAverageCorrection -eq 0 ]; then
		cpucount_makeLoadAverage="${cpucount_makeJobs}.00"
	else
		local remainingLoadAveragePercentage=$((100 - configuredLoadAverageCorrection))
		local reducedCpus=$((cpucount_makeJobs - 1))
		cpucount_makeLoadAverage="${reducedCpus}.${remainingLoadAveragePercentage}"
		if [ $cpucount_makeLoadAverage = '0.00' ]; then
			cpucount_makeLoadAverage=0.01
		fi
	fi
}