vppinfra: added performance test for clib_rwlock_t (test_rwlock.c)

Spawns a uniform number of writer and reader threads across a number of
cores where each writer thread increments a global variable a specified
number of times, and the reader threads continually poll the global's
value until the writers complete.

Type: test

Change-Id: I979c3734c6d03139d0802bff1846875d226f6fbb
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, 264 insertions, 0 deletions

diff --git a/src/vppinfra/test_rwlock.c b/src/vppinfra/test_rwlock.c
new file mode 100644
index 00000000000..8b6f927d63e
--- /dev/null
+++ b/src/vppinfra/test_rwlock.c
@@ -0,0 +1,264 @@
+/*
+ * 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 <vppinfra/atomics.h>
+
+static u32 all_threads_online = 0;
+
+typedef struct
+{
+  uword threads_per_core;
+  uword cpu_mask_read;
+  uword read_cores;
+  uword cpu_mask_write;
+  uword write_cores;
+  uword increment_per_thread;
+  clib_rwlock_t rwlock;
+  uword shared_count;
+  uword iterations;
+} rwlock_test_main_t;
+
+void *
+write_shared_counter (void *arg)
+{
+  f64 *time = vec_new (f64, 1);
+  *time = 0;
+  rwlock_test_main_t *rtm = 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 < rtm->increment_per_thread; i++)
+    {
+      clib_rwlock_writer_lock (&rtm->rwlock);
+      rtm->shared_count++;
+      clib_rwlock_writer_unlock (&rtm->rwlock);
+    }
+  *time = clib_cpu_time_now () - start;
+  return time;
+}
+
+void *
+read_shared_counter (void *arg)
+{
+  f64 *time = vec_new (f64, 1);
+  *time = 0;
+  rwlock_test_main_t *rtm = arg;
+  uword cnt_cpy = 0, exp = rtm->increment_per_thread * rtm->write_cores *
+    rtm->threads_per_core;
+
+  /* Wait for all threads to be created */
+  while (!clib_atomic_load_acq_n (&all_threads_online));
+
+  f64 start = clib_cpu_time_now ();
+  while (cnt_cpy < exp)
+    {
+      clib_rwlock_reader_lock (&rtm->rwlock);
+      cnt_cpy = rtm->shared_count;
+      clib_rwlock_reader_unlock (&rtm->rwlock);
+    }
+  *time = clib_cpu_time_now () - start;
+  return time;
+}
+
+unsigned
+test_rwlock (rwlock_test_main_t * rtm, f64 * elapse_time)
+{
+  int error = 0, total_threads = (rtm->read_cores + rtm->write_cores)
+    * rtm->threads_per_core;
+  pthread_t pthread[total_threads];
+
+  cpu_set_t cpuset;
+  unsigned cores_set = 0, cpu_id = 0;
+
+  /* Spawn reader (consumer) threads */
+  for (unsigned cpu_mask = rtm->cpu_mask_read; 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 < rtm->threads_per_core; t_num++)
+	{
+	  uword t_index = cores_set * rtm->threads_per_core + t_num;
+	  if (error = pthread_create (&pthread[t_index], NULL,
+				      &read_shared_counter, rtm))
+	    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_set_affinity_np failed with %d",
+			       error);
+	}
+      cores_set++;
+      cpu_id++;
+    }
+
+  /* Spawn writer (producer) threads */
+  cpu_id = 0;
+  for (unsigned cpu_mask = rtm->cpu_mask_write; 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 < rtm->threads_per_core; t_num++)
+	{
+	  uword t_index = cores_set * rtm->threads_per_core + t_num;
+	  if (error = pthread_create (&pthread[t_index], NULL,
+				      &write_shared_counter, rtm))
+	    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_set_affinity_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 < total_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\n", *elapse_time);
+  return rtm->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_rwlock_main (unformat_input_t * i)
+{
+  rwlock_test_main_t _rtm, *rtm = &_rtm;
+  clib_memset (rtm, 0, sizeof (rwlock_test_main_t));
+
+  while (unformat_check_input (i) != UNFORMAT_END_OF_INPUT)
+    {
+      if (0 == unformat (i, "threads/core %d", &rtm->threads_per_core)
+	  && 0 == unformat (i, "cpu_mask_read %x", &rtm->cpu_mask_read)
+	  && 0 == unformat (i, "cpu_mask_write %x", &rtm->cpu_mask_write)
+	  && 0 == unformat (i, "increment %d", &rtm->increment_per_thread)
+	  && 0 == unformat (i, "iterations %d", &rtm->iterations))
+	{
+	  clib_unix_warning ("unknown input '%U'", format_unformat_error, i);
+	  return 1;
+	}
+    }
+
+  rtm->read_cores = num_cores_in_cpu_mask (rtm->cpu_mask_read);
+  rtm->write_cores = num_cores_in_cpu_mask (rtm->cpu_mask_write);
+
+  uword total_increment = rtm->threads_per_core * rtm->write_cores *
+    rtm->increment_per_thread;
+
+  clib_rwlock_init (&rtm->rwlock);
+
+  f64 average_time = 0;
+  for (uword trial = 0; trial < rtm->iterations; trial++)
+    {
+      rtm->shared_count = 0;
+      f64 elapse_time = 0;
+      if (test_rwlock (rtm, &elapse_time) != total_increment)
+	{
+	  clib_rwlock_free (&rtm->rwlock);
+	  fformat (stdout, "FAILED: expected count: %d, actual count: %d\n",
+		   total_increment, rtm->shared_count);
+	  return 1;
+	}
+      fformat (stdout, "Trial %d SUCCESS: %d = %d\n",
+	       trial, rtm->shared_count, total_increment);
+      average_time = (average_time * trial + elapse_time) / (trial + 1);
+      fformat (stdout, "Average lock/unlock cycles: %.4e\n", average_time);
+    }
+  clib_rwlock_free (&rtm->rwlock);
+  return 0;
+}
+
+#ifdef CLIB_UNIX
+/** Launches a number of writer threads to simultaneously increment a global
+    counter and a number of reader threads to continuously poll the counter,
+    and records timestamps for rwlock performance benchmarking
+
+    @param "threads/core [# threads/core]" - number of threads per core
+    @param "cpu_mask_read [cpu_mask]" - reader thread cpu string e.g. input
+            ff sets cpus 0 - 7
+    @param "cpu_mask_write [cpu_mask]" - writer thread cpu string
+    @param "increment [# increments]" - number of increments per writer thread
+    @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_rwlock_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:
+ */