1 /* SPDX-License-Identifier: Apache-2.0
2 * Copyright(c) 2022 Cisco Systems, Inc.
5 #include <cnat/cnat_maglev.h>
8 cnat_maglev_perm_compare (void *_a, void *_b)
10 return *(u64 *) _b - *(u64 *) _a;
14 * Maglev algorithm implementation. This takes permutation as input,
15 * with the values of offset & skip for the backends.
16 * It fills buckets matching the permuntations, provided buckets is
17 * already of length at least M
20 cnat_maglev_shuffle (cnat_maglev_perm_t *permutation, u32 *buckets)
22 u32 N, M, i, done = 0;
25 N = vec_len (permutation);
29 M = vec_len (buckets);
30 vec_set (buckets, -1);
32 vec_validate (next, N - 1);
37 for (i = 0; i < N; i++)
39 u32 c = (permutation[i].offset + next[i] * permutation[i].skip) % M;
40 while (buckets[c] != (u32) -1)
43 c = (permutation[i].offset + next[i] * permutation[i].skip) % M;
46 buckets[c] = permutation[i].index;
60 cnat_translation_init_maglev (cnat_translation_t *ct)
62 cnat_maglev_perm_t *permutations = NULL;
63 cnat_main_t *cm = &cnat_main;
65 u32 backend_index = 0;
67 if (vec_len (ct->ct_active_paths) == 0)
70 vec_foreach (trk, ct->ct_active_paths)
72 cnat_maglev_perm_t permutation;
75 if (AF_IP4 == ip_addr_version (&trk->ct_ep[VLIB_TX].ce_ip))
78 a = ip_addr_v4 (&trk->ct_ep[VLIB_TX].ce_ip).data_u32;
79 b = (u64) trk->ct_ep[VLIB_TX].ce_port;
81 hash_v3_mix32 (a, b, c);
82 hash_v3_finalize32 (a, b, c);
89 a = ip_addr_v6 (&trk->ct_ep[VLIB_TX].ce_ip).as_u64[0];
90 b = ip_addr_v6 (&trk->ct_ep[VLIB_TX].ce_ip).as_u64[1];
91 c = (u64) trk->ct_ep[VLIB_TX].ce_port;
97 permutation.offset = h1 % cm->maglev_len;
98 permutation.skip = h2 % (cm->maglev_len - 1) + 1;
99 permutation.index = backend_index++;
101 if (trk->ct_flags & CNAT_TRK_FLAG_TEST_DISABLED)
104 vec_add1 (permutations, permutation);
107 vec_sort_with_function (permutations, cnat_maglev_perm_compare);
109 vec_validate (ct->lb_maglev, cm->maglev_len - 1);
111 cnat_maglev_shuffle (permutations, ct->lb_maglev);
113 vec_free (permutations);
117 cnat_u32_vec_contains (u32 *v, u32 e)
121 vec_foreach_index (i, v)
129 cnat_maglev_print_changes (vlib_main_t *vm, u32 *changed_bk_indices,
130 u32 *old_maglev_lb, u32 *new_maglev_lb)
132 u32 good_flow_buckets = 0, reset_flow_buckets = 0, stable_to_reset = 0;
133 u32 reset_to_stable = 0, switched_stable = 0;
134 for (u32 i = 0; i < vec_len (new_maglev_lb); i++)
137 cnat_u32_vec_contains (changed_bk_indices, new_maglev_lb[i]);
139 cnat_u32_vec_contains (changed_bk_indices, old_maglev_lb[i]);
140 if (new_maglev_lb[i] == old_maglev_lb[i])
143 reset_flow_buckets++;
151 else if (is_old_changed)
158 "good B->B:%d | lost A->A':%d A->B:%d ~%0.2f%% | bad "
159 "B->A':%d B->C:%d ~%0.2f%%",
160 good_flow_buckets, reset_flow_buckets, reset_to_stable,
161 (f64) (reset_flow_buckets + reset_to_stable) /
162 vec_len (new_maglev_lb) * 100.0,
163 stable_to_reset, switched_stable,
164 (f64) (stable_to_reset + switched_stable) /
165 vec_len (new_maglev_lb) * 100.0);
169 format_cnat_maglev_buckets (u8 *s, va_list *args)
171 u32 *buckets = va_arg (*args, u32 *);
172 u32 backend_idx = va_arg (*args, u32);
173 u32 count = va_arg (*args, u32);
175 for (u32 ii = 0; ii < vec_len (buckets); ii++)
176 if (buckets[ii] == backend_idx)
178 s = format (s, "%d,", ii);
185 static clib_error_t *
186 cnat_translation_test_init_maglev (vlib_main_t *vm, unformat_input_t *input,
187 vlib_cli_command_t *cmd)
189 cnat_translation_t *trs = 0, *ct;
190 u64 num_backends = 0, n_tests = 0;
191 cnat_main_t *cm = &cnat_main;
194 u32 n_changes = 0, n_remove = 0, verbose = 0;
196 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
198 if (unformat (input, "tests %d", &n_tests))
200 else if (unformat (input, "backends %d", &num_backends))
202 else if (unformat (input, "len %d", &cm->maglev_len))
204 else if (unformat (input, "change %d", &n_changes))
206 else if (unformat (input, "rm %d", &n_remove))
208 else if (unformat (input, "verbose %d", &verbose))
211 return (clib_error_return (0, "unknown input '%U'",
212 format_unformat_error, input));
215 if (num_backends == 0 || n_tests == 0)
216 return (clib_error_return (0, "No backends / tests to run"));
219 vlib_cli_output (vm, "generating random backends...");
220 rnd = random_default_seed ();
222 vec_validate (trs, n_tests - 1);
223 vec_foreach (ct, trs)
225 vec_validate (ct->ct_active_paths, num_backends - 1);
226 vec_foreach (trk, ct->ct_active_paths)
229 ip_addr_version (&trk->ct_ep[VLIB_TX].ce_ip) = AF_IP4;
230 ip_addr_v4 (&trk->ct_ep[VLIB_TX].ce_ip).data_u32 = random_u32 (&rnd);
231 trk->ct_ep[VLIB_TX].ce_port = random_u32 (&rnd);
235 vlib_cli_output (vm, "testing...");
236 f64 start_time = vlib_time_now (vm);
237 vec_foreach (ct, trs)
238 cnat_translation_init_maglev (ct);
239 f64 d = vlib_time_now (vm) - start_time;
241 vlib_cli_output (vm, "Test took : %U", format_duration, d);
242 vlib_cli_output (vm, "Per pool : %U", format_duration, d / n_tests);
244 /* sanity checking of the output */
245 u32 *backend_freqs = 0;
246 vec_validate (backend_freqs, num_backends - 1);
247 vec_foreach (ct, trs)
249 if (vec_len (ct->lb_maglev) != cm->maglev_len)
250 vlib_cli_output (vm, "Unexpected bucket length %d",
251 vec_len (ct->lb_maglev));
253 vec_zero (backend_freqs);
254 for (u32 i = 0; i < vec_len (ct->lb_maglev); i++)
256 if (ct->lb_maglev[i] >= num_backends)
257 clib_warning ("out of bound backend");
258 backend_freqs[ct->lb_maglev[i]]++;
260 u32 fmin = ~0, fmax = 0;
261 for (u32 i = 0; i < num_backends; i++)
263 if (backend_freqs[i] > fmax)
264 fmax = backend_freqs[i];
265 if (backend_freqs[i] < fmin)
266 fmin = backend_freqs[i];
268 f64 fdiff = (fmax - fmin);
269 if (fdiff / vec_len (ct->lb_maglev) - 1 > 0.02)
270 vlib_cli_output (vm, "More than 2%% frequency diff (min %d max %d)",
273 vec_free (backend_freqs);
277 vec_foreach (ct, trs)
279 vlib_cli_output (vm, "Translation %d", i++);
280 for (u32 i = 0; i < verbose; i++)
282 u32 j = random_u32 (&rnd) % vec_len (ct->ct_active_paths);
283 trk = &ct->ct_active_paths[j];
285 vm, "[%03d] %U:%d buckets:%U", j, format_ip_address,
286 &trk->ct_ep[VLIB_TX].ce_ip, trk->ct_ep[VLIB_TX].ce_port,
287 format_cnat_maglev_buckets, ct->lb_maglev, j, verbose);
294 vm, "Removing %d entries (refered to as A), others (B,C) stay same",
296 vec_foreach (ct, trs)
298 u32 *old_maglev_lb = 0;
299 u32 *changed_bk_indices = 0;
300 if (vec_len (ct->lb_maglev) != cm->maglev_len)
301 vlib_cli_output (vm, "Unexpected bucket length %d",
302 vec_len (ct->lb_maglev));
304 vec_validate (changed_bk_indices, n_remove - 1);
305 for (u32 i = 0; i < n_remove; i++)
307 /* remove n_remove backends from the LB set */
308 changed_bk_indices[i] =
309 random_u32 (&rnd) % vec_len (ct->ct_active_paths);
310 trk = &ct->ct_active_paths[changed_bk_indices[i]];
311 trk->ct_flags |= CNAT_TRK_FLAG_TEST_DISABLED;
314 old_maglev_lb = vec_dup (ct->lb_maglev);
315 cnat_translation_init_maglev (ct);
317 cnat_maglev_print_changes (vm, changed_bk_indices, old_maglev_lb,
320 vec_free (changed_bk_indices);
321 vec_free (old_maglev_lb);
325 /* Reshuffle and check changes */
330 "Changing %d entries (refered to as A->A'), others (B,C) stay same",
332 vec_foreach (ct, trs)
334 if (vec_len (ct->lb_maglev) != cm->maglev_len)
335 vlib_cli_output (vm, "Unexpected bucket length %d",
336 vec_len (ct->lb_maglev));
338 u32 *old_maglev_lb = 0;
339 u32 *changed_bk_indices = 0;
341 vec_validate (changed_bk_indices, n_changes - 1);
342 for (u32 i = 0; i < n_changes; i++)
344 /* Change n_changes backends in the LB set */
345 changed_bk_indices[i] =
346 random_u32 (&rnd) % vec_len (ct->ct_active_paths);
347 trk = &ct->ct_active_paths[changed_bk_indices[i]];
348 ip_addr_v4 (&trk->ct_ep[VLIB_TX].ce_ip).data_u32 =
350 trk->ct_ep[VLIB_TX].ce_port = random_u32 (&rnd) & 0xffff;
352 old_maglev_lb = vec_dup (ct->lb_maglev);
354 cnat_translation_init_maglev (ct);
355 cnat_maglev_print_changes (vm, changed_bk_indices, old_maglev_lb,
358 vec_free (changed_bk_indices);
359 vec_free (old_maglev_lb);
363 vec_foreach (ct, trs)
364 vec_free (ct->ct_active_paths);
370 VLIB_CLI_COMMAND (cnat_translation_test_init_maglev_cmd, static) = {
371 .path = "test cnat maglev",
372 .short_help = "test cnat maglev tests [n_tests] backends [num_backends] len "
374 .function = cnat_translation_test_init_maglev,