[PATCH 1/3] selftests/powerpc: Fix TM tests when CPU 0 is offline

[PATCH 1/3] selftests/powerpc: Fix TM tests when CPU 0 is offline

[Michael Ellerman]

Several of the TM tests fail spuriously if CPU 0 is offline, because
they blindly try to affinitise to CPU 0.

Fix them by picking any online CPU and using that instead.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 tools/testing/selftests/powerpc/tm/tm-poison.c      | 11 +++++++----
 tools/testing/selftests/powerpc/tm/tm-trap.c        | 10 ++++++----
 tools/testing/selftests/powerpc/tm/tm-unavailable.c |  9 ++++++---
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-poison.c b/tools/testing/selftests/powerpc/tm/tm-poison.c
index 977558497c16..29e5f26af7b9 100644
--- a/tools/testing/selftests/powerpc/tm/tm-poison.c
+++ b/tools/testing/selftests/powerpc/tm/tm-poison.c
@@ -26,7 +26,7 @@
 
 int tm_poison_test(void)
 {
-	int pid;
+	int cpu, pid;
 	cpu_set_t cpuset;
 	uint64_t poison = 0xdeadbeefc0dec0fe;
 	uint64_t unknown = 0;
@@ -35,10 +35,13 @@ int tm_poison_test(void)
 
 	SKIP_IF(!have_htm());
 
-	/* Attach both Child and Parent to CPU 0 */
+	cpu = pick_online_cpu();
+	FAIL_IF(cpu < 0);
+
+	// Attach both Child and Parent to the same CPU
 	CPU_ZERO(&cpuset);
-	CPU_SET(0, &cpuset);
-	sched_setaffinity(0, sizeof(cpuset), &cpuset);
+	CPU_SET(cpu, &cpuset);
+	FAIL_IF(sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0);
 
 	pid = fork();
 	if (!pid) {
diff --git a/tools/testing/selftests/powerpc/tm/tm-trap.c b/tools/testing/selftests/powerpc/tm/tm-trap.c
index 601f0c1d450d..c75960af8018 100644
--- a/tools/testing/selftests/powerpc/tm/tm-trap.c
+++ b/tools/testing/selftests/powerpc/tm/tm-trap.c
@@ -247,8 +247,7 @@ void *pong(void *not_used)
 int tm_trap_test(void)
 {
 	uint16_t k = 1;
-
-	int rc;
+	int cpu, rc;
 
 	pthread_attr_t attr;
 	cpu_set_t cpuset;
@@ -267,9 +266,12 @@ int tm_trap_test(void)
 	usr1_sa.sa_sigaction = usr1_signal_handler;
 	sigaction(SIGUSR1, &usr1_sa, NULL);
 
-	/* Set only CPU 0 in the mask. Both threads will be bound to cpu 0. */
+	cpu = pick_online_cpu();
+	FAIL_IF(cpu < 0);
+
+	// Set only one CPU in the mask. Both threads will be bound to that CPU.
 	CPU_ZERO(&cpuset);
-	CPU_SET(0, &cpuset);
+	CPU_SET(cpu, &cpuset);
 
 	/* Init pthread attribute */
 	rc = pthread_attr_init(&attr);
diff --git a/tools/testing/selftests/powerpc/tm/tm-unavailable.c b/tools/testing/selftests/powerpc/tm/tm-unavailable.c
index 2ca2fccb0a3e..a1348a5f721a 100644
--- a/tools/testing/selftests/powerpc/tm/tm-unavailable.c
+++ b/tools/testing/selftests/powerpc/tm/tm-unavailable.c
@@ -338,16 +338,19 @@ void test_fp_vec(int fp, int vec, pthread_attr_t *attr)
 
 int tm_unavailable_test(void)
 {
-	int rc, exception; /* FP = 0, VEC = 1, VSX = 2 */
+	int cpu, rc, exception; /* FP = 0, VEC = 1, VSX = 2 */
 	pthread_t t1;
 	pthread_attr_t attr;
 	cpu_set_t cpuset;
 
 	SKIP_IF(!have_htm());
 
-	/* Set only CPU 0 in the mask. Both threads will be bound to CPU 0. */
+	cpu = pick_online_cpu();
+	FAIL_IF(cpu < 0);
+
+	// Set only one CPU in the mask. Both threads will be bound to that CPU.
 	CPU_ZERO(&cpuset);
-	CPU_SET(0, &cpuset);
+	CPU_SET(cpu, &cpuset);
 
 	/* Init pthread attribute. */
 	rc = pthread_attr_init(&attr);
-- 
2.25.1

[PATCH 2/3] selftests/powerpc: Don't use setaffinity in tm-tmspr

[Michael Ellerman]

This test tries to set affinity to CPUs that don't exist, especially
if the set of online CPUs doesn't start at 0.

But there's no real reason for it to use setaffinity in the first
place, it's just trying to create lots of threads to cause contention.
So drop the setaffinity entirely.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 tools/testing/selftests/powerpc/tm/tm-tmspr.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-tmspr.c b/tools/testing/selftests/powerpc/tm/tm-tmspr.c
index 17becf3dcee4..2ff329e2fca9 100644
--- a/tools/testing/selftests/powerpc/tm/tm-tmspr.c
+++ b/tools/testing/selftests/powerpc/tm/tm-tmspr.c
@@ -38,14 +38,8 @@ int	passed = 1;
 
 void tfiar_tfhar(void *in)
 {
-	int i, cpu;
 	unsigned long tfhar, tfhar_rd, tfiar, tfiar_rd;
-	cpu_set_t cpuset;
-
-	CPU_ZERO(&cpuset);
-	cpu = (unsigned long)in >> 1;
-	CPU_SET(cpu, &cpuset);
-	sched_setaffinity(0, sizeof(cpuset), &cpuset);
+	int i;
 
 	/* TFIAR: Last bit has to be high so userspace can read register */
 	tfiar = ((unsigned long)in) + 1;
-- 
2.25.1

[PATCH 3/3] selftests/powerpc: Run tm-tmspr test for longer

[Michael Ellerman]

This test creates some threads, which write to TM SPRs, and then makes
sure the registers maintain the correct values across context switches
and contention with other threads.

But currently the test finishes almost instantaneously, which reduces
the chance of it hitting an interesting condition.

So increase the number of loops, so it runs a bit longer, though still
less than 2s on a Power8.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 tools/testing/selftests/powerpc/tm/tm-tmspr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-tmspr.c b/tools/testing/selftests/powerpc/tm/tm-tmspr.c
index 2ff329e2fca9..794d574db784 100644
--- a/tools/testing/selftests/powerpc/tm/tm-tmspr.c
+++ b/tools/testing/selftests/powerpc/tm/tm-tmspr.c
@@ -33,7 +33,7 @@
 #include "utils.h"
 #include "tm.h"
 
-int	num_loops	= 10000;
+int	num_loops	= 1000000;
 int	passed = 1;
 
 void tfiar_tfhar(void *in)
-- 
2.25.1

Re: [PATCH 1/3] selftests/powerpc: Fix TM tests when CPU 0 is offline

[Michael Ellerman]

On Thu, 13 Aug 2020 11:34:43 +1000, Michael Ellerman wrote:
> Several of the TM tests fail spuriously if CPU 0 is offline, because
> they blindly try to affinitise to CPU 0.
> 
> Fix them by picking any online CPU and using that instead.

Applied to powerpc/next.

[1/3] selftests/powerpc: Fix TM tests when CPU 0 is offline
      https://git.kernel.org/powerpc/c/c0176429b7b07893a5c1fd38baff055c919ba9e3
[2/3] selftests/powerpc: Don't use setaffinity in tm-tmspr
      https://git.kernel.org/powerpc/c/769628710c33b18ede837bb488e1d24084b35592
[3/3] selftests/powerpc: Run tm-tmspr test for longer
      https://git.kernel.org/powerpc/c/b5a646a681f5d67ea5190a71d6e84a91efe63b7a

cheers