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Subject[PATCH 4/7] selftests/resctrl: Add built in benchmark
Date
From: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>

Built-in benchmark fill_buf generates stressful memory bandwidth
and cache traffic.

Later it will be used as a default benchmark by various resctrl tests
such as MBA (Memory Bandwidth Allocation) and MBM (Memory Bandwidth
Monitoring) tests.

Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Arshiya Hayatkhan Pathan <arshiya.hayatkhan.pathan@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
tools/testing/selftests/resctrl/fill_buf.c | 178 +++++++++++++++++++++++++++++
1 file changed, 178 insertions(+)
create mode 100644 tools/testing/selftests/resctrl/fill_buf.c

diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
new file mode 100644
index 000000000000..a94d1e83a736
--- /dev/null
+++ b/tools/testing/selftests/resctrl/fill_buf.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fill_buf benchmark
+ *
+ * Copyright (C) 2018 Intel Corporation
+ *
+ * Authors:
+ * Arshiya Hayatkhan Pathan <arshiya.hayatkhan.pathan@intel.com>
+ * Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
+ * Fenghua Yu <fenghua.yu@intel.com>
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <inttypes.h>
+#include <malloc.h>
+#include <string.h>
+
+#include "resctrl.h"
+
+#define CL_SIZE (64)
+#define PAGE_SIZE (4 * 1024)
+#define MB (1024 * 1024)
+
+static unsigned char *startptr;
+
+static void sb(void)
+{
+ asm volatile("sfence\n\t"
+ : : : "memory");
+}
+
+static void ctrl_handler(int signo)
+{
+ free(startptr);
+ printf("\nEnding\n");
+ sb();
+ exit(EXIT_SUCCESS);
+}
+
+static void cl_flush(void *p)
+{
+ asm volatile("clflush (%0)\n\t"
+ : : "r"(p) : "memory");
+}
+
+static void mem_flush(void *p, size_t s)
+{
+ char *cp = (char *)p;
+ size_t i = 0;
+
+ s = s / CL_SIZE; /* mem size in cache llines */
+
+ for (i = 0; i < s; i++)
+ cl_flush(&cp[i * CL_SIZE]);
+
+ sb();
+}
+
+static void *malloc_and_init_memory(size_t s)
+{
+ uint64_t *p64;
+ size_t s64;
+
+ void *p = memalign(PAGE_SIZE, s);
+
+ p64 = (uint64_t *)p;
+ s64 = s / sizeof(uint64_t);
+
+ while (s64 > 0) {
+ *p64 = (uint64_t) rand();
+ p64 += (CL_SIZE / sizeof(uint64_t));
+ s64 -= (CL_SIZE / sizeof(uint64_t));
+ }
+
+ return p;
+}
+
+static void fill_cache_read(unsigned char *start_ptr, unsigned char *end_ptr)
+{
+ while (1) {
+ unsigned char sum, *p;
+
+ p = start_ptr;
+ /* Read two chars in each cache line to stress cache */
+ while (p < (end_ptr - 1024)) {
+ sum += p[0] + p[32] + p[64] + p[96] + p[128] +
+ p[160] + p[192] + p[224] + p[256] + p[288] +
+ p[320] + p[352] + p[384] + p[416] + p[448] +
+ p[480] + p[512] + p[544] + p[576] + p[608] +
+ p[640] + p[672] + p[704] + p[736] + p[768] +
+ p[800] + p[832] + p[864] + p[896] + p[928] +
+ p[960] + p[992];
+ p += 1024;
+ }
+ }
+}
+
+static void fill_cache_write(unsigned char *start_ptr, unsigned char *end_ptr)
+{
+ while (1) {
+ while (start_ptr < end_ptr) {
+ *start_ptr = '1';
+ start_ptr += (CL_SIZE / 2);
+ }
+ start_ptr = startptr;
+ }
+}
+
+static void
+fill_cache(unsigned long long buf_size, int malloc_and_init,
+ int memflush, int op)
+{
+ unsigned char *start_ptr, *end_ptr;
+ unsigned long long i;
+
+ if (malloc_and_init) {
+ start_ptr = malloc_and_init_memory(buf_size);
+ printf("Started benchmark with memalign\n");
+ } else {
+ start_ptr = malloc(buf_size);
+ printf("Started benchmark with malloc\n");
+ }
+
+ if (start_ptr == NULL)
+ return;
+
+ startptr = start_ptr;
+ end_ptr = start_ptr + buf_size;
+
+ /*
+ * It's better to touch the memory once to avoid any compiler
+ * optimizations
+ */
+ if (!malloc_and_init) {
+ for (i = 0; i < buf_size; i++)
+ *start_ptr++ = (unsigned char)rand();
+ }
+
+ start_ptr = startptr;
+
+ /* Flush the memory before using to avoid "cache hot pages" effect */
+ if (memflush) {
+ mem_flush(start_ptr, buf_size);
+ printf("Started benchmark with memflush\n");
+ } else {
+ printf("Started benchmark *without* memflush\n");
+ }
+
+ if (op == 0)
+ fill_cache_read(start_ptr, end_ptr);
+ else
+ fill_cache_write(start_ptr, end_ptr);
+
+ free(startptr);
+
+ exit(EXIT_FAILURE);
+}
+
+int run_fill_buf(int span, int malloc_and_init_memory, int memflush, int op)
+{
+ unsigned long long cache_size = span * MB;
+
+ /* set up ctrl-c handler */
+ if (signal(SIGINT, ctrl_handler) == SIG_ERR)
+ printf("Failed to catch SIGINT!\n");
+ if (signal(SIGHUP, ctrl_handler) == SIG_ERR)
+ printf("Failed to catch SIGHUP!\n");
+
+ printf("Cache size in Bytes = %llu\n", cache_size);
+
+ fill_cache(cache_size, malloc_and_init_memory, memflush, op);
+ printf("Unable to allocate memory\n");
+
+ exit(EXIT_FAILURE);
+}
--
2.5.0
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