diff --git a/src/engine/jam.cpp b/src/engine/jam.cpp
index 08c826bdc..850b30e01 100644
--- a/src/engine/jam.cpp
+++ b/src/engine/jam.cpp
@@ -272,6 +272,7 @@ int main( int argc, char * * argv, char * * arg_environ )
     char            const * progname = argv[ 0 ];
     module_t              * environ_module;
     int                     is_debugger;
+    b2::system_info sys_info;
 
     saved_argv0 = argv[ 0 ];
 
@@ -362,23 +363,23 @@ int main( int argc, char * * argv, char * * arg_environ )
         usage( progname );
     }
 
+    /* Set default parallel jobs to match cpu threads. This can be overridden
+    the usual way with -jX or PARALLELISM env var. */
+    globs.jobs = sys_info.cpu_thread_count();
+
     /* Version info. */
     if ( ( s = getoptval( optv, 'v', 0 ) ) )
     {
         out_printf( "B2 Version %s. %s.\n", VERSION, OSMINOR );
-        out_printf( "   Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.\n" );
-        out_printf( "   Copyright 2001 David Turner.\n" );
-        out_printf( "   Copyright 2001-2004 David Abrahams.\n" );
-        out_printf( "   Copyright 2002-2019 Rene Rivera.\n" );
-        out_printf( "   Copyright 2003-2015 Vladimir Prus.\n" );
+        out_printf( "  Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.\n" );
+        out_printf( "  Copyright 2001 David Turner.\n" );
+        out_printf( "  Copyright 2001-2004 David Abrahams.\n" );
+        out_printf( "  Copyright 2002-2019 Rene Rivera.\n" );
+        out_printf( "  Copyright 2003-2015 Vladimir Prus.\n" );
+        out_printf( "\n  DEFAULTS: jobs = %i\n", globs.jobs);
         return EXITOK;
     }
 
-    /* Set default parallel jobs to match cpu threads. This can be overridden
-    the usual way with -jX or PARALLELISM env var. */
-    b2::system_info sys_info;
-    globs.jobs = sys_info.cpu_thread_count();
-
     /* Pick up interesting options. */
     if ( ( s = getoptval( optv, 'n', 0 ) ) )
     {
diff --git a/src/engine/sysinfo.cpp b/src/engine/sysinfo.cpp
index b5c46e1fe..2dad17f19 100644
--- a/src/engine/sysinfo.cpp
+++ b/src/engine/sysinfo.cpp
@@ -7,41 +7,103 @@
 #include "jam.h"
 #include "output.h"
 
+#include <thread>
+
 #if defined(OS_MACOSX)
 #include <sys/types.h>
 #include <sys/sysctl.h>
 #endif
+
 #if !defined(OS_NT)
 #include <unistd.h>
 #endif
 
-#include <thread>
+#if defined(OS_LINUX)
+#define _GNU_SOURCE
+#include <sched.h>
+#undef _GNU_SOURCE
+#endif
 
 
 b2::system_info::system_info()
 {
 }
 
-unsigned int b2::system_info::cpu_core_count()
+namespace
 {
-    if (cpu_core_count_ == 0)
+    unsigned int macosx_physicalcpu()
     {
         #if defined(OS_MACOSX)
         int out_hw_ncpu = 0;
         size_t len_hw_ncpu = sizeof(out_hw_ncpu);
         int result = ::sysctlbyname(
             "hw.physicalcpu", &out_hw_ncpu, &len_hw_ncpu, nullptr, 0);
-        if (result == 0)
-        {
-            cpu_core_count_ = out_hw_ncpu;
-        }
-        #elif defined(_SC_NPROCESSORS_CONF)
-        cpu_thread_count_ = ::sysconf(_SC_NPROCESSORS_CONF);
+        if (result == 0) return out_hw_ncpu;
         #endif
-        if (cpu_core_count_ <= 0)
+        return 0;
+    }
+
+    unsigned int macosx_logicalcpu()
+    {
+        #if defined(OS_MACOSX)
+        int out_hw_ncpu = 0;
+        size_t len_hw_ncpu = sizeof(out_hw_ncpu);
+        int result = ::sysctlbyname(
+            "hw.logicalcpu", &out_hw_ncpu, &len_hw_ncpu, nullptr, 0);
+        if (result == 0) return out_hw_ncpu;
+        #endif
+        return 0;
+    }
+
+    unsigned int sched_affinity_cpu_count()
+    {
+        #if defined(CPU_COUNT_S)
+        ::cpu_set_t cpu_set;
+        if (::sched_getaffinity(0, sizeof(cpu_set_t), &cpu_set) == 0)
         {
-            cpu_core_count_ = 1;
+            return CPU_COUNT_S(sizeof(cpu_set_t), &cpu_set);
         }
+        #endif
+        return 0;
+    }
+
+    unsigned int sysconf_nprocs_configured()
+    {
+        #if defined(_SC_NPROCESSORS_ONLN)
+        return ::sysconf(_SC_NPROCESSORS_CONF);
+        #else
+        return 0;
+        #endif
+    }
+
+    unsigned int sysconf_nprocs_online()
+    {
+        #if defined(_SC_NPROCESSORS_ONLN)
+        return ::sysconf(_SC_NPROCESSORS_ONLN);
+        #else
+        return 0;
+        #endif
+    }
+
+    unsigned int std_thread_hardware_concurrency()
+    {
+        return std::thread::hardware_concurrency();
+    }
+}
+
+unsigned int b2::system_info::cpu_core_count()
+{
+    if (cpu_core_count_ == 0)
+    {
+        cpu_thread_count_ = macosx_physicalcpu();
+    }
+    if (cpu_thread_count_ == 0)
+    {
+        cpu_thread_count_ = sysconf_nprocs_configured();
+    }
+    if (cpu_core_count_ <= 0)
+    {
+        cpu_core_count_ = 1;
     }
     return cpu_core_count_;
 }
@@ -50,24 +112,23 @@ unsigned int b2::system_info::cpu_thread_count()
 {
     if (cpu_thread_count_ == 0)
     {
-        #if defined(OS_MACOSX)
-        int out_hw_ncpu = 0;
-        size_t len_hw_ncpu = sizeof(out_hw_ncpu);
-        int result = ::sysctlbyname(
-            "hw.logicalcpu", &out_hw_ncpu, &len_hw_ncpu, nullptr, 0);
-        if (result == 0)
-        {
-            cpu_thread_count_ = out_hw_ncpu;
-        }
-        #elif defined(_SC_NPROCESSORS_ONLN)
-        cpu_thread_count_ = ::sysconf(_SC_NPROCESSORS_ONLN);
-        #else
-        cpu_thread_count_ = std::thread::hardware_concurrency();
-        #endif
-        if (cpu_thread_count_ <= 0)
-        {
-            cpu_thread_count_ = cpu_core_count();
-        }
+        cpu_thread_count_ = macosx_logicalcpu();
+    }
+    if (cpu_thread_count_ == 0)
+    {
+        cpu_thread_count_ = sched_affinity_cpu_count();
+    }
+    if (cpu_thread_count_ == 0)
+    {
+        cpu_thread_count_ = sysconf_nprocs_online();
+    }
+    if (cpu_thread_count_ == 0)
+    {
+        cpu_thread_count_ = std_thread_hardware_concurrency();
+    }
+    if (cpu_thread_count_ == 0)
+    {
+        cpu_thread_count_ = cpu_core_count();
     }
     return cpu_thread_count_;
 }