diff --git cctools/ld64/src/ld/InputFiles.cpp cctools/ld64/src/ld/InputFiles.cpp
index 13207e5..2b6f7bd 100644
--- cctools/ld64/src/ld/InputFiles.cpp
+++ cctools/ld64/src/ld/InputFiles.cpp
@@ -43,6 +43,15 @@
 #include <sys/sysctl.h>
 #include <libkern/OSAtomic.h>
 
+// ld64-port
+#ifdef __linux__
+#ifndef __USE_GNU
+#define __USE_GNU
+#endif
+#include <sched.h>
+#endif
+// ld64-port end
+
 #include <string>
 #include <map>
 #include <set>
@@ -913,6 +922,20 @@ InputFiles::InputFiles(Options& opts, const char** archName)
 	
 	// initialize info for parsing input files on worker threads
 	unsigned int ncpus;
+#ifdef __linux__ // ld64-port
+	cpu_set_t cs;
+	CPU_ZERO(&cs);
+
+	if (!sched_getaffinity(0, sizeof(cs), &cs)) {
+		ncpus = 0;
+
+		for (int i = 0; i < CPU_SETSIZE; i++)
+			if (CPU_ISSET(i, &cs))
+				ncpus++;
+	} else {
+		ncpus = 1;
+	}
+#else
 	int mib[2];
 	size_t len = sizeof(ncpus);
 	mib[0] = CTL_HW;
@@ -920,6 +943,7 @@ InputFiles::InputFiles(Options& opts, const char** archName)
 	if (sysctl(mib, 2, &ncpus, &len, NULL, 0) != 0) {
 		ncpus = 1;
 	}
+#endif
 	_availableWorkers = MIN(ncpus, files.size()); // max # workers we permit
 	_idleWorkers = 0;