[PATCH v2] benchtests: Add malloc microbenchmark

[Will Newton <will dot newton at linaro dot org>]

Add a microbenchmark for measuring malloc and free performance. The
benchmark allocates and frees buffers of random sizes in a random
order and measures the overall execution time and RSS. Variants of the
benchmark are run with 8, 32 and 64 threads to measure the effect of
concurrency on allocator performance.

The random block sizes used follow an inverse square distribution
which is intended to mimic the behaviour of real applications which
tend to allocate many more small blocks than large ones.

ChangeLog:

2014-04-15  Will Newton  <will.newton@linaro.org>

	* benchtests/Makefile: (benchset): Add malloc benchmarks.
	Link threaded malloc benchmarks with libpthread.
	* benchtests/bench-malloc-threads-32.c: New file.
	* benchtests/bench-malloc-threads-64.c: Likewise.
	* benchtests/bench-malloc-threads-8.c: Likewise.
	* benchtests/bench-malloc.c: Likewise.
---
 benchtests/Makefile                  |   7 +-
 benchtests/bench-malloc-threads-32.c |  20 +++
 benchtests/bench-malloc-threads-64.c |  20 +++
 benchtests/bench-malloc-threads-8.c  |  20 +++
 benchtests/bench-malloc.c            | 236 +++++++++++++++++++++++++++++++++++
 5 files changed, 302 insertions(+), 1 deletion(-)
 create mode 100644 benchtests/bench-malloc-threads-32.c
 create mode 100644 benchtests/bench-malloc-threads-64.c
 create mode 100644 benchtests/bench-malloc-threads-8.c
 create mode 100644 benchtests/bench-malloc.c

Changes in v2:
 - Move random number generation out of the loop and use arrays of random
   values. This reduces the overhead of the benchmark loop to 10% or less.

diff --git a/benchtests/Makefile b/benchtests/Makefile
index a0954cd..f38380d 100644
--- a/benchtests/Makefile
+++ b/benchtests/Makefile
@@ -37,9 +37,11 @@ string-bench := bcopy bzero memccpy memchr memcmp memcpy memmem memmove \
 		strspn strstr strcpy_chk stpcpy_chk memrchr strsep strtok
 string-bench-all := $(string-bench)
 
+malloc-bench := malloc malloc-threads-8 malloc-threads-32 malloc-threads-64
+
 stdlib-bench := strtod
 
-benchset := $(string-bench-all) $(stdlib-bench)
+benchset := $(string-bench-all) $(stdlib-bench) $(malloc-bench)
 
 CFLAGS-bench-ffs.c += -fno-builtin
 CFLAGS-bench-ffsll.c += -fno-builtin
@@ -47,6 +49,9 @@ CFLAGS-bench-ffsll.c += -fno-builtin
 $(addprefix $(objpfx)bench-,$(bench-math)): $(common-objpfx)math/libm.so
 $(addprefix $(objpfx)bench-,$(bench-pthread)): \
 	$(common-objpfx)nptl/libpthread.so
+$(objpfx)bench-malloc-threads-8: $(common-objpfx)nptl/libpthread.so
+$(objpfx)bench-malloc-threads-32: $(common-objpfx)nptl/libpthread.so
+$(objpfx)bench-malloc-threads-64: $(common-objpfx)nptl/libpthread.so
 
 
 
diff --git a/benchtests/bench-malloc-threads-32.c b/benchtests/bench-malloc-threads-32.c
new file mode 100644
index 0000000..463ceb7
--- /dev/null
+++ b/benchtests/bench-malloc-threads-32.c
@@ -0,0 +1,20 @@
+/* Measure malloc and free functions with threads.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define NUM_THREADS 32
+#include "bench-malloc.c"
diff --git a/benchtests/bench-malloc-threads-64.c b/benchtests/bench-malloc-threads-64.c
new file mode 100644
index 0000000..61d8c10
--- /dev/null
+++ b/benchtests/bench-malloc-threads-64.c
@@ -0,0 +1,20 @@
+/* Measure malloc and free functions with threads.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define NUM_THREADS 64
+#include "bench-malloc.c"
diff --git a/benchtests/bench-malloc-threads-8.c b/benchtests/bench-malloc-threads-8.c
new file mode 100644
index 0000000..ac4ff79
--- /dev/null
+++ b/benchtests/bench-malloc-threads-8.c
@@ -0,0 +1,20 @@
+/* Measure malloc and free functions with threads.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define NUM_THREADS 8
+#include "bench-malloc.c"
diff --git a/benchtests/bench-malloc.c b/benchtests/bench-malloc.c
new file mode 100644
index 0000000..dc4fe17
--- /dev/null
+++ b/benchtests/bench-malloc.c
@@ -0,0 +1,236 @@
+/* Benchmark malloc and free functions.
+   Copyright (C) 2013-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include "bench-timing.h"
+#include "json-lib.h"
+
+#define BENCHMARK_ITERATIONS	40000000
+#define RAND_SEED		88
+
+#ifndef NUM_THREADS
+#define NUM_THREADS 1
+#endif
+
+/* Maximum memory that can be allocated at any one time is:
+
+   NUM_THREADS * WORKING_SET_SIZE * MAX_ALLOCATION_SIZE
+
+   However due to the distribution of the random block sizes
+   the typical amount allocated will be much smaller.  */
+#define WORKING_SET_SIZE	1024
+
+#define MIN_ALLOCATION_SIZE	4
+#define MAX_ALLOCATION_SIZE	32768
+
+/* Get a random block size with an inverse square distribution.  */
+static unsigned int
+get_block_size (unsigned int rand_data)
+{
+  /* Inverse square.  */
+  float exponent = -2;
+  /* Minimum value of distribution.  */
+  float dist_min = MIN_ALLOCATION_SIZE;
+  /* Maximum value of distribution.  */
+  float dist_max = MAX_ALLOCATION_SIZE;
+
+  float min_pow = powf (dist_min, exponent + 1);
+  float max_pow = powf (dist_max, exponent + 1);
+
+  float r = (float) rand_data / RAND_MAX;
+
+  return (unsigned int) powf ((max_pow - min_pow) * r + min_pow, 1 / (exponent + 1));
+}
+
+#define NUM_BLOCK_SIZES	8000
+#define NUM_OFFSETS	((WORKING_SET_SIZE) * 4)
+
+static unsigned int random_block_sizes[NUM_BLOCK_SIZES];
+static unsigned int random_offsets[NUM_OFFSETS];
+
+static void
+init_random_values (void)
+{
+  size_t i;
+
+  for (i = 0; i < NUM_BLOCK_SIZES; i++)
+    random_block_sizes[i] = get_block_size (rand ());
+
+  for (i = 0; i < NUM_OFFSETS; i++)
+    random_offsets[i] = rand () % WORKING_SET_SIZE;
+}
+
+static unsigned int
+get_random_block_size (unsigned int *state)
+{
+  unsigned int idx = *state;
+
+  if (idx >= NUM_BLOCK_SIZES - 1)
+    idx = 0;
+  else
+    idx++;
+
+  *state = idx;
+
+  return random_block_sizes[idx];
+}
+
+static unsigned int
+get_random_offset (unsigned int *state)
+{
+  unsigned int idx = *state;
+
+  if (idx >= NUM_OFFSETS - 1)
+    idx = 0;
+  else
+    idx++;
+
+  *state = idx;
+
+  return random_offsets[idx];
+}
+
+/* Allocate and free blocks in a random order.  */
+static void
+malloc_benchmark_loop (size_t iters, void **ptr_arr)
+{
+  size_t i;
+  unsigned int offset_state = 0, block_state = 0;
+
+  for (i = 0; i < iters; i++)
+    {
+      unsigned int next_idx = get_random_offset (&offset_state);
+      unsigned int next_block = get_random_block_size (&block_state);
+
+      free (ptr_arr[next_idx]);
+
+      ptr_arr[next_idx] = malloc (next_block);
+    }
+}
+
+static void *working_set[NUM_THREADS][WORKING_SET_SIZE];
+
+#if NUM_THREADS > 1
+static pthread_t threads[NUM_THREADS];
+
+struct thread_args
+{
+  size_t iters;
+  void **working_set;
+};
+
+static void *
+benchmark_thread (void *arg)
+{
+  struct thread_args *args = (struct thread_args *) arg;
+  size_t iters = args->iters;
+  void *thread_set = args->working_set;
+
+  malloc_benchmark_loop (iters, thread_set);
+
+  return NULL;
+}
+#endif
+
+static void
+do_benchmark (size_t iters)
+{
+#if NUM_THREADS == 1
+  malloc_benchmark_loop (iters, working_set[0]);
+#else
+  struct thread_args args[NUM_THREADS];
+
+  size_t i;
+
+  for (i = 0; i < NUM_THREADS; i++)
+    {
+      args[i].iters = iters;
+      args[i].working_set = working_set[i];
+      pthread_create(&threads[i], NULL, benchmark_thread, &args[i]);
+    }
+
+  for (i = 0; i < NUM_THREADS; i++)
+    pthread_join(threads[i], NULL);
+#endif
+}
+
+int
+main (int argc, char **argv)
+{
+  timing_t start, stop, cur;
+  size_t iters = BENCHMARK_ITERATIONS;
+  unsigned long res;
+  json_ctx_t json_ctx;
+  double d_total_s, d_total_i;
+
+  init_random_values ();
+
+  json_init (&json_ctx, 0, stdout);
+
+  json_document_begin (&json_ctx);
+
+  json_attr_string (&json_ctx, "timing_type", TIMING_TYPE);
+
+  json_attr_object_begin (&json_ctx, "functions");
+
+  json_attr_object_begin (&json_ctx, "malloc");
+
+  json_attr_object_begin (&json_ctx, "");
+
+  TIMING_INIT (res);
+
+  (void) res;
+
+  TIMING_NOW (start);
+  do_benchmark (iters);
+  TIMING_NOW (stop);
+
+  struct rusage usage;
+  getrusage(RUSAGE_SELF, &usage);
+
+  TIMING_DIFF (cur, start, stop);
+
+  d_total_s = cur;
+  d_total_i = iters * NUM_THREADS;
+
+  json_attr_double (&json_ctx, "duration", d_total_s);
+  json_attr_double (&json_ctx, "iterations", d_total_i);
+  json_attr_double (&json_ctx, "mean", d_total_s / d_total_i);
+  json_attr_double (&json_ctx, "max_rss", usage.ru_maxrss);
+
+  json_attr_double (&json_ctx, "threads", NUM_THREADS);
+  json_attr_double (&json_ctx, "min_size", MIN_ALLOCATION_SIZE);
+  json_attr_double (&json_ctx, "max_size", MAX_ALLOCATION_SIZE);
+  json_attr_double (&json_ctx, "random_seed", RAND_SEED);
+
+  json_attr_object_end (&json_ctx);
+
+  json_attr_object_end (&json_ctx);
+
+  json_attr_object_end (&json_ctx);
+
+  json_document_end (&json_ctx);
+
+  return 0;
+}
-- 
1.8.1.4