diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index efd9954..a6a4b9f 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -32,6 +32,9 @@
 #  include <windows.h>
 #endif
 
+#ifdef __VXWORKS__
+#  include "pycore_bitutils.h"    // _Py_popcount32()
+#endif
 #include "pycore_ceval.h"         // _PyEval_ReInitThreads()
 #include "pycore_import.h"        // _PyImport_ReInitLock()
 #include "pycore_initconfig.h"    // _PyStatus_EXCEPTION()
@@ -12607,6 +12610,8 @@
     ncpu = mpctl(MPC_GETNUMSPUS, NULL, NULL);
 #elif defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
     ncpu = sysconf(_SC_NPROCESSORS_ONLN);
+#elif defined(__VXWORKS__)
+    ncpu = _Py_popcount32(vxCpuEnabledGet());
 #elif defined(__DragonFly__) || \
       defined(__OpenBSD__)   || \
       defined(__FreeBSD__)   || \