vppinfra: added lock performance test for clib_spinlock_t (test_spinlock.c)

Spawns a uniform number of threads across a number of cores where each
thread increments a global variable a specified number of times.

Type: test

Change-Id: I12b3a37708a199c297d022348d99dbb0e8349a9f
Signed-off-by: Jason Zhang <jason.zhang2@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Lijian Zhang <Lijian.Zhang@arm.com>

1 files changed, 206 insertions, 0 deletions

diff --git a/src/vppinfra/test_spinlock.c b/src/vppinfra/test_spinlock.c
new file mode 100644
index 00000000000..fd750d9851c
--- /dev/null
+++ b/src/vppinfra/test_spinlock.c
@@ -0,0 +1,206 @@
+/*
+ * Copyright (c) 2019 Arm Limited.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <vppinfra/mem.h>
+#include <vppinfra/cache.h>
+#include <vppinfra/lock.h>
+#include <pthread.h>
+#include <vppinfra/format.h>
+#include <vppinfra/error.h>
+#include <vppinfra/time.h>
+#include <sched.h>
+#include <stdlib.h>
+#include <vppinfra/atomics.h>
+
+static u32 all_threads_online = 0;
+
+typedef struct
+{
+  uword threads_per_core;
+  uword cpu_mask;
+  uword num_cores;
+  uword increment_per_thread;
+  clib_spinlock_t slock;
+  uword shared_count;
+  uword iterations;
+} spinlock_test_main_t;
+
+void *
+inc_shared_counter (void *arg)
+{
+  f64 *time = vec_new (f64, 1);
+  *time = 0;
+  spinlock_test_main_t *stm = arg;
+
+  /* Wait for all threads to be created */
+  while (!clib_atomic_load_acq_n (&all_threads_online));
+
+  f64 start = clib_cpu_time_now ();
+  for (uword i = 0; i < stm->increment_per_thread; i++)
+    {
+      clib_spinlock_lock (&stm->slock);
+      stm->shared_count++;
+      clib_spinlock_unlock (&stm->slock);
+    }
+  *time = clib_cpu_time_now () - start;
+  return time;
+}
+
+unsigned
+test_spinlock (spinlock_test_main_t * stm, f64 * elapse_time)
+{
+  int error;
+  uword num_threads = stm->num_cores * stm->threads_per_core;
+  pthread_t pthread[num_threads];
+
+  cpu_set_t cpuset;
+  unsigned cores_set = 0, cpu_id = 0;
+  for (unsigned cpu_mask = stm->cpu_mask; cpu_mask; cpu_mask >>= 1)
+    {
+      if (!(cpu_mask & 1))
+	{
+	  cpu_id++;
+	  continue;
+	}
+
+      CPU_ZERO (&cpuset);
+      CPU_SET (cpu_id, &cpuset);
+      for (uword t_num = 0; t_num < stm->threads_per_core; t_num++)
+	{
+	  uword t_index = cores_set * stm->threads_per_core + t_num;
+	  if (error = pthread_create (&pthread[t_index], NULL,
+				      &inc_shared_counter, stm))
+	    clib_unix_warning ("pthread_create failed with %d", error);
+
+	  if (error = pthread_setaffinity_np (pthread[t_index],
+					      sizeof (cpu_set_t), &cpuset))
+	    clib_unix_warning ("pthread_setaffinity_np failed with %d",
+			       error);
+	}
+      cores_set++;
+      cpu_id++;
+    }
+
+  /* Launch all threads */
+  clib_atomic_store_rel_n (&all_threads_online, 1);
+
+  for (uword thread_num = 0; thread_num < num_threads; thread_num++)
+    {
+      f64 *time;
+      if (error = pthread_join (pthread[thread_num], (void *) &time))
+	clib_unix_warning ("pthread_join failed with %d", error);
+      *elapse_time += *time;
+      vec_free (time);
+    }
+
+  fformat (stdout, "Time elapsed: %.4e cycles\n", *elapse_time);
+  return stm->shared_count;
+}
+
+uword
+num_cores_in_cpu_mask (uword mask)
+{
+  uword num_cores = 0;
+  for (uword cpu_mask = mask; cpu_mask; cpu_mask >>= 1)
+    num_cores += (cpu_mask & 1);
+  return num_cores;
+}
+
+int
+test_spinlock_main (unformat_input_t * i)
+{
+  spinlock_test_main_t _stm, *stm = &_stm;
+  clib_memset (stm, 0, sizeof (spinlock_test_main_t));
+
+  while (unformat_check_input (i) != UNFORMAT_END_OF_INPUT)
+    {
+      if (0 == unformat (i, "threads/core %d", &stm->threads_per_core)
+	  && 0 == unformat (i, "cpu_mask %x", &stm->cpu_mask)
+	  && 0 == unformat (i, "increment %d", &stm->increment_per_thread)
+	  && 0 == unformat (i, "iterations %d", &stm->iterations))
+	{
+	  clib_unix_warning ("unknown input '%U'", format_unformat_error, i);
+	  return 1;
+	}
+    }
+
+  stm->num_cores = num_cores_in_cpu_mask (stm->cpu_mask);
+
+  uword total_increment = stm->threads_per_core * stm->num_cores *
+    stm->increment_per_thread;
+
+  clib_spinlock_init (&stm->slock);
+
+  f64 average_time = 0;
+  for (uword trial = 0; trial < stm->iterations; trial++)
+    {
+      stm->shared_count = 0;
+      f64 elapse_time = 0;
+      if (test_spinlock (stm, &elapse_time) != total_increment)
+	{
+	  clib_spinlock_free (&stm->slock);
+	  fformat (stdout, "FAILED: expected count: %d, actual count: %d\n",
+		   total_increment, stm->shared_count);
+	  return 1;
+	}
+
+      fformat (stdout, "Trial %d SUCCESS: %d = %d\n",
+	       trial, stm->shared_count, total_increment);
+      average_time = (average_time * trial + elapse_time) / (trial + 1);
+      fformat (stdout, "Average lock/unlock cycles %.4e\n", average_time);
+    }
+  clib_spinlock_free (&stm->slock);
+  return 0;
+}
+
+#ifdef CLIB_UNIX
+/** Launches a number of threads to simultaneously increment a global
+    counter, and records timestamps for spinlock performance benchmarking
+
+    @param "threads/core [# threads/core]" - number of threads per core
+    @param "cpu_mask [cpu_mask]" - cpu hex string e.g. input ff sets cpus 0 - 7
+    @param "increment [# increments]" - number of increments per threads
+    @param "iterations [# iterations]" - number of iterations
+    @returns exit code
+*/
+int
+main (int argc, char *argv[])
+{
+  unformat_input_t i;
+  i32 ret;
+  clib_time_t time;
+
+  clib_mem_init (0, 3ULL << 30);
+  clib_time_init (&time);
+
+  unformat_init_command_line (&i, argv);
+  ret = test_spinlock_main (&i);
+  unformat_free (&i);
+
+  return ret;
+}
+#endif /* CLIB_UNIX */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */