diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index 60dbe12d2..8e2ed946f 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -33,10 +33,7 @@
                     "message": 5
                 }
             },
-            "group": {
-                "kind": "build",
-                "isDefault": true
-            }
+            "group": "build"
         },
         {
             "label": "B2 Engine Infer",
diff --git a/doc/src/history.adoc b/doc/src/history.adoc
index 68908489e..23a81932f 100644
--- a/doc/src/history.adoc
+++ b/doc/src/history.adoc
@@ -23,3 +23,6 @@ Other changes in this release:
 * Add s390x CPU and support in gcc/clang. -- _Neale Ferguson_
 * Support importing pkg-config packages. -- _Dmitry Arkhipov_
 * Support for leak sanitizer. -- _Damian Jarek_
+* Fix missing `/manifest` option in clang-win to fix admin elevation for exes with "update" in the name. -- Peter Dimov
+* Add `freertos` to `os` feature. -- tee3
+* Default parallel jobs (`-jX`) to the available CPU threads. -- _Rene Rivera_
diff --git a/src/engine/build.bat b/src/engine/build.bat
index 8f8f9c779..e0233afed 100644
--- a/src/engine/build.bat
+++ b/src/engine/build.bat
@@ -175,7 +175,7 @@ set B2_SOURCES=%B2_SOURCES% glob.cpp hash.cpp hcache.cpp hdrmacro.cpp headers.cp
 set B2_SOURCES=%B2_SOURCES% jambase.cpp jamgram.cpp lists.cpp make.cpp make1.cpp md5.cpp mem.cpp modules.cpp
 set B2_SOURCES=%B2_SOURCES% native.cpp object.cpp option.cpp output.cpp parse.cpp pathnt.cpp
 set B2_SOURCES=%B2_SOURCES% pathsys.cpp regexp.cpp rules.cpp scan.cpp search.cpp strings.cpp
-set B2_SOURCES=%B2_SOURCES% subst.cpp timestamp.cpp variable.cpp w32_getreg.cpp
+set B2_SOURCES=%B2_SOURCES% subst.cpp sysinfo.cpp timestamp.cpp variable.cpp w32_getreg.cpp
 set B2_SOURCES=%B2_SOURCES% modules/order.cpp
 set B2_SOURCES=%B2_SOURCES% modules/path.cpp
 set B2_SOURCES=%B2_SOURCES% modules/property-set.cpp
diff --git a/src/engine/build.sh b/src/engine/build.sh
index 85c205e20..a1e4cd335 100755
--- a/src/engine/build.sh
+++ b/src/engine/build.sh
@@ -415,6 +415,7 @@ B2_SOURCES="\
  search.cpp \
  strings.cpp \
  subst.cpp \
+ sysinfo.cpp \
  timestamp.cpp \
  variable.cpp \
  w32_getreg.cpp \
diff --git a/src/engine/jam.cpp b/src/engine/jam.cpp
index b6185ba60..08c826bdc 100644
--- a/src/engine/jam.cpp
+++ b/src/engine/jam.cpp
@@ -134,6 +134,7 @@
 #include "timestamp.h"
 #include "variable.h"
 #include "execcmd.h"
+#include "sysinfo.h"
 
 /* Macintosh is "special" */
 #ifdef OS_MAC
@@ -373,6 +374,11 @@ int main( int argc, char * * argv, char * * arg_environ )
         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
new file mode 100644
index 000000000..f72121eac
--- /dev/null
+++ b/src/engine/sysinfo.cpp
@@ -0,0 +1,62 @@
+/*  Copyright 2019 Rene Rivera
+ *  Distributed under the Boost Software License, Version 1.0.
+ *  (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+#include "sysinfo.h"
+#include "jam.h"
+#include "output.h"
+
+#ifdef OS_MACOSX
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#endif
+
+
+b2::system_info::system_info()
+{
+}
+
+unsigned int b2::system_info::cpu_core_count()
+{
+    if (cpu_core_count_ == 0)
+    {
+        #ifdef 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;
+        }
+        #endif
+        if (cpu_core_count_ == 0)
+        {
+            cpu_core_count_ = 1;
+        }
+    }
+    return cpu_core_count_;
+}
+
+unsigned int b2::system_info::cpu_thread_count()
+{
+    if (cpu_thread_count_ == 0)
+    {
+        #ifdef 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;
+        }
+        #endif
+        if (cpu_thread_count_ == 0)
+        {
+            cpu_thread_count_ = cpu_core_count();
+        }
+    }
+    return cpu_thread_count_;
+}
diff --git a/src/engine/sysinfo.h b/src/engine/sysinfo.h
new file mode 100644
index 000000000..28c42558f
--- /dev/null
+++ b/src/engine/sysinfo.h
@@ -0,0 +1,46 @@
+/*  Copyright 2019 Rene Rivera
+ *  Distributed under the Boost Software License, Version 1.0.
+ *  (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef B2_SYSINFO_H
+#define B2_SYSINFO_H
+
+# include "config.h"
+
+namespace b2
+{
+    /*
+    Provides information about the system, hardware and software, we are
+    running in.
+    */
+    class system_info
+    {
+        public:
+
+        system_info();
+
+        /*
+        Returns the number of physical CPU cores if available. Otherwise
+        returns 1.
+
+        Currently implemented for: OS_MACOSX.
+        */
+        unsigned int cpu_core_count();
+
+        /*
+        Returns the number of logical CPU threads is available. Otherwise
+        returns `spu_core_count()`.
+
+        Currently implemented for: OS_MACOSX.
+        */
+        unsigned int cpu_thread_count();
+
+        private:
+
+        unsigned int cpu_core_count_ = 0;
+        unsigned int cpu_thread_count_ = 0;
+    };
+}
+
+#endif