--- /dev/null
+++ Libc/Libc-1244.20.1/tests/psort.c
@@ -0,0 +1,71 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <mach/clock_types.h>
+#include <TargetConditionals.h>
+
+#include <darwintest.h>
+
+typedef unsigned long T;
+
+static int
+comparT(const void* a, const void* b) {
+	const T x = *(T*)a, y = *(T*)b;
+	return x < y ? -1 : x > y ? 1 : 0;
+}
+
+T_DECL(psort, "psort(3)")
+{
+	struct timeval tv_start, tv_stop;
+	struct rusage ru_start, ru_stop;
+	uint64_t pwt, put, qwt, qut;
+
+	T *buf, *sorted;
+#if TARGET_OS_BRIDGE
+	const size_t nel = 2048000;
+#else
+	const size_t nel = 20480000;
+#endif
+	const size_t width = sizeof(T), bufsiz = nel * width;
+
+	buf = malloc(bufsiz);
+	arc4random_buf(buf, bufsiz);
+	sorted = malloc(bufsiz);
+	memcpy(sorted, buf, bufsiz);
+
+	getrusage(RUSAGE_SELF, &ru_start);
+	gettimeofday(&tv_start, NULL);
+	psort(sorted, nel, width, comparT);
+	gettimeofday(&tv_stop, NULL);
+	getrusage(RUSAGE_SELF, &ru_stop);
+
+	pwt = ((uint64_t)tv_stop.tv_sec * USEC_PER_SEC + tv_stop.tv_usec) -
+			((uint64_t)tv_start.tv_sec * USEC_PER_SEC + tv_start.tv_usec);
+	put = ((uint64_t)ru_stop.ru_utime.tv_sec * USEC_PER_SEC + ru_stop.ru_utime.tv_usec) -
+			((uint64_t)ru_start.ru_utime.tv_sec * USEC_PER_SEC + ru_start.ru_utime.tv_usec);
+	T_LOG("psort: wall-time=%llu us; user-time=%llu us", pwt, put);
+
+	getrusage(RUSAGE_SELF, &ru_start);
+	gettimeofday(&tv_start, NULL);
+	qsort(buf, nel, width, comparT);
+	gettimeofday(&tv_stop, NULL);
+	getrusage(RUSAGE_SELF, &ru_stop);
+
+	qwt = ((uint64_t)tv_stop.tv_sec * USEC_PER_SEC + tv_stop.tv_usec) -
+			((uint64_t)tv_start.tv_sec * USEC_PER_SEC + tv_start.tv_usec);
+	qut = ((uint64_t)ru_stop.ru_utime.tv_sec * USEC_PER_SEC + ru_stop.ru_utime.tv_usec) -
+			((uint64_t)ru_start.ru_utime.tv_sec * USEC_PER_SEC + ru_start.ru_utime.tv_usec);
+	T_LOG("qsort: wall-time=%llu us; user-time=%llu us", qwt, qut);
+
+	for (size_t i = 0; i < nel; i++) {
+		if (buf[i] != sorted[i]) {
+			T_ASSERT_EQ(buf[i], sorted[i], NULL);
+		}
+	}
+
+	free(sorted);
+	free(buf);
+
+	T_EXPECT_LE((double)pwt/qwt, 1.2, "psort/qsort wall time");
+	T_EXPECT_LE((double)qut/put, 1.2, "qsort/psort user time");
+}