From 7e25d69608a1cad5ee74d53bbf411b5948da08ee Mon Sep 17 00:00:00 2001
From: IISergII <serg_eronov@rambler.ru>
Date: Tue, 2 Jun 2020 22:52:01 +0300
Subject: [PATCH] platform_linux.cpp: Added sysconf use for
 s_numPhysicalCPUCores when parsing /proc/cpuinfo fails, an alternative method
 will be used - sysconf() to get s_numPhysicalCPUCores value

---
 neo/sys/posix/platform_linux.cpp | 33 ++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/neo/sys/posix/platform_linux.cpp b/neo/sys/posix/platform_linux.cpp
index 6859d5a9..ecce63bb 100644
--- a/neo/sys/posix/platform_linux.cpp
+++ b/neo/sys/posix/platform_linux.cpp
@@ -45,6 +45,11 @@ static const char** cmdargv = NULL;
 static int cmdargc = 0;
 // DG end
 
+// RB begin
+#include <stdio.h> // needed for sysconf()
+#include <cstring>
+// RB end
+
 #ifdef ID_MCHECK
 	#include <mcheck.h>
 #endif
@@ -164,8 +169,8 @@ double Sys_ClockTicksPerSecond()
 ========================
 Sys_CPUCount
 
-numLogicalCPUCores	- the number of logical CPU per core
-numPhysicalCPUCores	- the total number of cores per package
+numLogicalCPUCores	- the total number of logical CPU cores (equal to the total number of threads from all CPU)
+numPhysicalCPUCores	- the total number of physical CPU cores
 numCPUPackages		- the total number of packages (physical processors)
 ========================
 */
@@ -173,6 +178,8 @@ numCPUPackages		- the total number of packages (physical processors)
 void Sys_CPUCount( int& numLogicalCPUCores, int& numPhysicalCPUCores, int& numCPUPackages )
 {
 	static bool		init = false;
+	static bool		CPUCoresIsFound = false; // needed for sysconf()
+	static bool		SiblingsIsFound = false; // needed for sysconf()
 	static double	ret;
 
 	static int		s_numLogicalCPUCores;
@@ -217,11 +224,13 @@ void Sys_CPUCount( int& numLogicalCPUCores, int& numPhysicalCPUCores, int& numCP
 					if( ( processor ) > s_numPhysicalCPUCores )
 					{
 						s_numPhysicalCPUCores = processor;
+						CPUCoresIsFound = true;
 					}
 				}
 				else
 				{
 					common->Printf( "failed parsing /proc/cpuinfo\n" );
+					CPUCoresIsFound = false;
 					break;
 				}
 			}
@@ -240,17 +249,37 @@ void Sys_CPUCount( int& numLogicalCPUCores, int& numPhysicalCPUCores, int& numCP
 					if( ( coreId ) > s_numLogicalCPUCores )
 					{
 						s_numLogicalCPUCores = coreId;
+						SiblingsIsFound = true;
 					}
 				}
 				else
 				{
 					common->Printf( "failed parsing /proc/cpuinfo\n" );
+					SiblingsIsFound = false;
 					break;
 				}
 			}
 
 			pos = strchr( buf + pos, '\n' ) - buf + 1;
 		}
+		if( CPUCoresIsFound == false && SiblingsIsFound == false)
+		{
+			common->Printf( "failed parsing /proc/cpuinfo\n" );
+			common->Printf( "alternative method used\n" );
+			s_numPhysicalCPUCores = sysconf(_SC_NPROCESSORS_CONF); // _SC_NPROCESSORS_ONLN may not be reliable on Android
+			s_numLogicalCPUCores = s_numPhysicalCPUCores; // hack for CPU without Hyper-Threading (HT) technology
+		}
+		else if( CPUCoresIsFound == true && SiblingsIsFound == false)
+		{
+			s_numLogicalCPUCores = s_numPhysicalCPUCores; // hack for CPU without Hyper-Threading (HT) technology
+		}
+	}
+	else
+	{
+		common->Printf( "failed to read /proc/cpuinfo\n" );
+		common->Printf( "alternative method used\n" );
+		s_numPhysicalCPUCores = sysconf(_SC_NPROCESSORS_CONF); // _SC_NPROCESSORS_ONLN may not be reliable on Android
+		s_numLogicalCPUCores = s_numPhysicalCPUCores; // hack for CPU without Hyper-Threading (HT) technology
 	}
 
 	common->Printf( "/proc/cpuinfo CPU processors: %d\n", s_numPhysicalCPUCores );