Adjust pass/fail criteria in dispatch_concur

Adjust pass/fail criteria to allow some divergence
when the level of expected concurrency is greater
than the number of hardware CPUs on the system on
which the test is being run.

Author: dgrove-oss

tests/dispatch_concur.c

@@ -31,6 +31,8 @@
 
 static volatile size_t done, concur;
 static int use_group_async;
+static uint32_t activecpu;
+static int32_t xfail = 0;
 
 static dispatch_queue_t q;
 static dispatch_group_t g, gw;
@@ -92,15 +94,28 @@ test_concur_async(size_t n, size_t qw)
 
 	dispatch_group_wait(g, DISPATCH_TIME_FOREVER);
 
-	test_long("concurrently completed workers", done,
-			MIN(n * workers, qw >= n ? qw - n : 0));
+	if (qw > 1) {
+		size_t concurrency = MIN(n * workers, qw);
+		if (concurrency > done && done >= activecpu) {
+			xfail++;
+		} else {
+			test_long("concurrently completed workers", done, concurrency);
+		}
+	} else {
+		test_long_less_than_or_equal("concurrently completed workers", done, 1);
+	}
 
 	for (i = 0, mc = mcs; i < n; i++, mc++) {
 		if (*mc > max_concur) max_concur = *mc;
 	}
 	free(mcs);
 
-	test_long("max submission concurrency", max_concur, MIN(n, qw));
+	size_t expect = MIN(n, qw);
+	if (expect > max_concur && max_concur >= activecpu) {
+		xfail++;
+	} else {
+		test_long("max submission concurrency", max_concur, expect);
+	}
 
 	dispatch_group_wait(gw, DISPATCH_TIME_FOREVER);
 	usleep(1000);
@@ -138,7 +153,12 @@ test_concur_sync(size_t n, size_t qw)
 	}
 	free(mcs);
 
-	test_long("max sync concurrency", max_concur, qw == 1 ? 1 : n);
+	size_t expect = qw == 1 ? 1 : n;
+	if (expect > max_concur && max_concur >= activecpu) {
+		xfail++;
+	} else {
+		test_long("max sync concurrency", max_concur, expect);
+	}
 }
 
 static void
@@ -164,7 +184,12 @@ test_concur_apply(size_t n, size_t qw)
 	}
 	free(mcs);
 
-	test_long("max apply concurrency", max_concur, MIN(n, qw));
+	size_t expect = MIN(n, qw);
+	if (expect > max_concur && max_concur >= activecpu) {
+		xfail++;
+	} else {
+		test_long("max apply concurrency", max_concur, expect);
+	}
 }
 
 static dispatch_queue_t
@@ -201,7 +226,6 @@ main(int argc __attribute__((unused)), char* argv[] __attribute__((unused)))
 {
 	dispatch_test_start("Dispatch Private Concurrent/Wide Queue"); // <rdar://problem/8049506&8169448&8186485>
 
-	uint32_t activecpu;
 #ifdef __linux__
 	activecpu = sysconf(_SC_NPROCESSORS_ONLN);
 #else
@@ -250,6 +274,8 @@ main(int argc __attribute__((unused)), char* argv[] __attribute__((unused)))
 		dispatch_release(ttq);
 	}
 
+	test_long_less_than_or_equal("6 failures for this test is acceptable", xfail, 6);
+
 	dispatch_release(g);
 	dispatch_release(gw);