1 /*
2 * Ones' complement checksum test & benchmark
3 *
4 * Copyright (c) 2016-2020, Arm Limited.
5 * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
6 */
7
8 #define _GNU_SOURCE
9 #include <inttypes.h>
10 #include <stdbool.h>
11 #include <stdint.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <sys/mman.h>
16 #include <time.h>
17 #include <unistd.h>
18 #include "../include/networking.h"
19
20 #if WANT_ASSERT
21 #undef NDEBUG
22 #include <assert.h>
23 #define Assert(exp) assert(exp)
24 #else
25 #define Assert(exp) (void) (exp)
26 #endif
27
28 #ifdef __GNUC__
29 #define may_alias __attribute__((__may_alias__))
30 #else
31 #define may_alias
32 #endif
33
34 #define CACHE_LINE 64
35 #define ALIGN(x, y) (((x) + (y) - 1) & ~((y) - 1))
36
37 /* Reference implementation - do not modify! */
38 static uint16_t
checksum_simple(const void * ptr,uint32_t nbytes)39 checksum_simple(const void *ptr, uint32_t nbytes)
40 {
41 const uint16_t *may_alias hptr = ptr;
42 uint64_t sum = 0;/* Need 64-bit accumulator when nbytes > 64K */
43
44 /* Sum all halfwords, assume misaligned accesses are handled in HW */
45 for (uint32_t nhalfs = nbytes >> 1; nhalfs != 0; nhalfs--)
46 {
47 sum += *hptr++;
48 }
49
50 /* Add any trailing odd byte */
51 if ((nbytes & 0x01) != 0)
52 {
53 sum += *(uint8_t *) hptr;
54 }
55
56 /* Fold 64-bit sum to 32 bits */
57 sum = (sum & 0xffffffff) + (sum >> 32);
58 sum = (sum & 0xffffffff) + (sum >> 32);
59 Assert(sum == (uint32_t) sum);
60
61 /* Fold 32-bit sum to 16 bits */
62 sum = (sum & 0xffff) + (sum >> 16);
63 sum = (sum & 0xffff) + (sum >> 16);
64 Assert(sum == (uint16_t) sum);
65
66 return (uint16_t) sum;
67 }
68
69 static struct
70 {
71 uint16_t (*cksum_fp)(const void *, uint32_t);
72 const char *name;
73 } implementations[] =
74 {
75 { checksum_simple, "simple"},
76 { __chksum, "scalar"},
77 #if __arm__
78 { __chksum_arm_simd, "simd" },
79 #elif __aarch64__
80 { __chksum_aarch64_simd, "simd" },
81 #endif
82 { NULL, NULL}
83 };
84
85 static int
find_impl(const char * name)86 find_impl(const char *name)
87 {
88 for (int i = 0; implementations[i].name != NULL; i++)
89 {
90 if (strcmp(implementations[i].name, name) == 0)
91 {
92 return i;
93 }
94 }
95 return -1;
96 }
97
98 static uint16_t (*CKSUM_FP)(const void *, uint32_t);
99 static volatile uint16_t SINK;
100
101 static bool
verify(const void * data,uint32_t offset,uint32_t size)102 verify(const void *data, uint32_t offset, uint32_t size)
103 {
104
105 uint16_t csum_expected = checksum_simple(data, size);
106 uint16_t csum_actual = CKSUM_FP(data, size);
107 if (csum_actual != csum_expected)
108 {
109 fprintf(stderr, "\nInvalid checksum for offset %u size %u: "
110 "actual %04x expected %04x (valid)",
111 offset, size, csum_actual, csum_expected);
112 if (size < 65536)
113 {
114 /* Fatal error */
115 exit(EXIT_FAILURE);
116 }
117 /* Else some implementations only support sizes up to 2^16 */
118 return false;
119 }
120 return true;
121 }
122
123 static uint64_t
clock_get_ns(void)124 clock_get_ns(void)
125 {
126 struct timespec ts;
127 clock_gettime(CLOCK_MONOTONIC, &ts);
128 return ts.tv_sec * (uint64_t) 1000000000 + ts.tv_nsec;
129 }
130
131 static void
benchmark(const uint8_t * base,size_t poolsize,uint32_t blksize,uint32_t numops,uint64_t cpufreq)132 benchmark(const uint8_t *base,
133 size_t poolsize,
134 uint32_t blksize,
135 uint32_t numops,
136 uint64_t cpufreq)
137 {
138 printf("%11u ", (unsigned int) blksize); fflush(stdout);
139
140 uint64_t start = clock_get_ns();
141 for (uint32_t i = 0; i < numops; i ++)
142 {
143 /* Read a random value from the pool */
144 uint32_t random = ((uint32_t *) base)[i % (poolsize / 4)];
145 /* Generate a random starting address */
146 const void *data = &base[random % (poolsize - blksize)];
147 SINK = CKSUM_FP(data, blksize);
148 }
149 uint64_t end = clock_get_ns();
150
151 #define MEGABYTE 1000000 /* Decimal megabyte (MB) */
152 uint64_t elapsed_ns = end - start;
153 uint64_t elapsed_ms = elapsed_ns / 1000000;
154 uint32_t blks_per_s = (uint32_t) ((numops / elapsed_ms) * 1000);
155 uint64_t accbytes = (uint64_t) numops * blksize;
156 printf("%11ju ", (uintmax_t) ((accbytes / elapsed_ms) * 1000) / MEGABYTE);
157 unsigned int cyc_per_blk = cpufreq / blks_per_s;
158 printf("%11u ", cyc_per_blk);
159 if (blksize != 0)
160 {
161 unsigned int cyc_per_byte = 1000 * cyc_per_blk / blksize;
162 printf("%7u.%03u ",
163 cyc_per_byte / 1000, cyc_per_byte % 1000);
164 }
165 printf("\n");
166 }
167
main(int argc,char * argv[])168 int main(int argc, char *argv[])
169 {
170 int c;
171 bool DUMP = false;
172 uint32_t IMPL = 0;/* Simple implementation */
173 uint64_t CPUFREQ = 0;
174 uint32_t BLKSIZE = 0;
175 uint32_t NUMOPS = 1000000;
176 uint32_t POOLSIZE = 512 * 1024;/* Typical ARM L2 cache size */
177
178 setvbuf(stdout, NULL, _IOLBF, 160);
179 while ((c = getopt(argc, argv, "b:df:i:n:p:")) != -1)
180 {
181 switch (c)
182 {
183 case 'b' :
184 {
185 int blksize = atoi(optarg);
186 if (blksize < 1 || blksize > POOLSIZE / 2)
187 {
188 fprintf(stderr, "Invalid block size %d\n", blksize);
189 exit(EXIT_FAILURE);
190 }
191 BLKSIZE = (unsigned) blksize;
192 break;
193 }
194 case 'd' :
195 DUMP = true;
196 break;
197 case 'f' :
198 {
199 int64_t cpufreq = atoll(optarg);
200 if (cpufreq < 1)
201 {
202 fprintf(stderr, "Invalid CPU frequency %"PRId64"\n",
203 cpufreq);
204 exit(EXIT_FAILURE);
205 }
206 CPUFREQ = cpufreq;
207 break;
208 }
209 case 'i' :
210 {
211 int impl = find_impl(optarg);
212 if (impl < 0)
213 {
214 fprintf(stderr, "Invalid implementation %s\n", optarg);
215 goto usage;
216 }
217 IMPL = (unsigned) impl;
218 break;
219 }
220 case 'n' :
221 {
222 int numops = atoi(optarg);
223 if (numops < 1)
224 {
225 fprintf(stderr, "Invalid number of operations %d\n", numops);
226 exit(EXIT_FAILURE);
227 }
228 NUMOPS = (unsigned) numops;
229 break;
230 }
231 case 'p' :
232 {
233 int poolsize = atoi(optarg);
234 if (poolsize < 4096)
235 {
236 fprintf(stderr, "Invalid pool size %d\n", poolsize);
237 exit(EXIT_FAILURE);
238 }
239 char c = optarg[strlen(optarg) - 1];
240 if (c == 'M')
241 {
242 POOLSIZE = (unsigned) poolsize * 1024 * 1024;
243 }
244 else if (c == 'K')
245 {
246 POOLSIZE = (unsigned) poolsize * 1024;
247 }
248 else
249 {
250 POOLSIZE = (unsigned) poolsize;
251 }
252 break;
253 }
254 default :
255 usage :
256 fprintf(stderr, "Usage: checksum <options>\n"
257 "-b <blksize> Block size\n"
258 "-d Dump first 96 bytes of data\n"
259 "-f <cpufreq> CPU frequency (Hz)\n"
260 "-i <impl> Implementation\n"
261 "-n <numops> Number of operations\n"
262 "-p <poolsize> Pool size (K or M suffix)\n"
263 );
264 printf("Implementations:");
265 for (int i = 0; implementations[i].name != NULL; i++)
266 {
267 printf(" %s", implementations[i].name);
268 }
269 printf("\n");
270 exit(EXIT_FAILURE);
271 }
272 }
273 if (optind > argc)
274 {
275 goto usage;
276 }
277
278 CKSUM_FP = implementations[IMPL].cksum_fp;
279 POOLSIZE = ALIGN(POOLSIZE, CACHE_LINE);
280 uint8_t *base = mmap(0, POOLSIZE, PROT_READ|PROT_WRITE,
281 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
282 if (base == MAP_FAILED)
283 {
284 perror("aligned_alloc"), exit(EXIT_FAILURE);
285 }
286 for (size_t i = 0; i < POOLSIZE / 4; i++)
287 {
288 ((uint32_t *) base)[i] = rand();
289 }
290
291 printf("Implementation: %s\n", implementations[IMPL].name);
292 printf("numops %u, poolsize ", NUMOPS);
293 if (POOLSIZE % (1024 * 1024) == 0)
294 {
295 printf("%uMiB", POOLSIZE / (1024 * 1024));
296 }
297 else if (POOLSIZE % 1024 == 0)
298 {
299 printf("%uKiB", POOLSIZE / 1024);
300 }
301 else
302 {
303 printf("%uB", POOLSIZE);
304 }
305 printf(", blocksize %u, CPU frequency %juMHz\n",
306 BLKSIZE, (uintmax_t) (CPUFREQ / 1000000));
307 #if WANT_ASSERT
308 printf("Warning: assertions are enabled\n");
309 #endif
310
311 if (DUMP)
312 {
313 /* Print out first 96 bytes of data for human debugging */
314 for (int i = 0; i < 96; i++)
315 {
316 if (i % 8 == 0)
317 printf("%2u:", i);
318 printf(" %02x", base[i]);
319 if (i % 8 == 7)
320 printf("\n");
321 }
322 }
323
324 /* Verify that chosen algorithm handles all combinations of offsets and sizes */
325 printf("Verifying..."); fflush(stdout);
326 bool success = true;
327 /* Check all (relevant) combinations of size and offset */
328 for (int size = 0; size <= 256; size++)
329 {
330 for (int offset = 0; offset < 255; offset++)
331 {
332 /* Check at start of mapped memory */
333 success &= verify(&base[offset], offset, size);
334 /* Check at end of mapped memory */
335 uint8_t *p = base + POOLSIZE - (size + offset);
336 success &= verify(p, (uintptr_t) p % 64, size);
337 }
338 }
339 /* Check increasingly larger sizes */
340 for (size_t size = 1; size < POOLSIZE; size *= 2)
341 {
342 success &= verify(base, 0, size);
343 }
344 /* Check the full size, this can detect accumulator overflows */
345 success &= verify(base, 0, POOLSIZE);
346 printf("%s\n", success ? "OK" : "failure");
347
348 /* Print throughput in decimal megabyte (1000000B) per second */
349 if (CPUFREQ != 0)
350 {
351 printf("%11s %11s %11s %11s\n",
352 "block size", "MB/s", "cycles/blk", "cycles/byte");
353 }
354 else
355 {
356 printf("%11s %11s %11s %11s\n",
357 "block size", "MB/s", "ns/blk", "ns/byte");
358 CPUFREQ = 1000000000;
359 }
360 if (BLKSIZE != 0)
361 {
362 benchmark(base, POOLSIZE, BLKSIZE, NUMOPS, CPUFREQ);
363 }
364 else
365 {
366 static const uint16_t sizes[] =
367 { 20, 42, 102, 250, 612, 1500, 3674, 9000, 0 };
368 for (int i = 0; sizes[i] != 0; i++)
369 {
370 uint32_t numops = NUMOPS * 10000 / (40 + sizes[i]);
371 benchmark(base, POOLSIZE, sizes[i], numops, CPUFREQ);
372 }
373 }
374
375 if (munmap(base, POOLSIZE) != 0)
376 {
377 perror("munmap"), exit(EXIT_FAILURE);
378 }
379
380 return success ? EXIT_SUCCESS : EXIT_FAILURE;
381 }
382