1 /* SPDX-License-Identifier: BSD-3-Clause
2 * Copyright(c) 2018 Intel Corporation
7 #include <rte_string_fns.h>
8 #include <rte_mbuf_dyn.h>
10 #include <rte_cycles.h>
11 #include <rte_ethdev.h>
12 #include <rte_metrics.h>
13 #include <rte_memzone.h>
14 #include <rte_lcore.h>
16 #include "rte_latencystats.h"
18 /** Nano seconds per second */
19 #define NS_PER_SEC 1E9
21 /** Clock cycles per nano second */
23 latencystat_cycles_per_ns(void)
25 return rte_get_timer_hz() / NS_PER_SEC;
28 /* Macros for printing using RTE_LOG */
29 #define RTE_LOGTYPE_LATENCY_STATS RTE_LOGTYPE_USER1
31 static uint64_t timestamp_dynflag;
32 static int timestamp_dynfield_offset = -1;
34 static inline rte_mbuf_timestamp_t *
35 timestamp_dynfield(struct rte_mbuf *mbuf)
37 return RTE_MBUF_DYNFIELD(mbuf,
38 timestamp_dynfield_offset, rte_mbuf_timestamp_t *);
41 static const char *MZ_RTE_LATENCY_STATS = "rte_latencystats";
42 static int latency_stats_index;
43 static uint64_t samp_intvl;
44 static uint64_t timer_tsc;
45 static uint64_t prev_tsc;
47 struct rte_latency_stats {
48 float min_latency; /**< Minimum latency in nano seconds */
49 float avg_latency; /**< Average latency in nano seconds */
50 float max_latency; /**< Maximum latency in nano seconds */
51 float jitter; /** Latency variation */
52 rte_spinlock_t lock; /** Latency calculation lock */
55 static struct rte_latency_stats *glob_stats;
58 const struct rte_eth_rxtx_callback *cb;
61 static struct rxtx_cbs rx_cbs[RTE_MAX_ETHPORTS][RTE_MAX_QUEUES_PER_PORT];
62 static struct rxtx_cbs tx_cbs[RTE_MAX_ETHPORTS][RTE_MAX_QUEUES_PER_PORT];
64 struct latency_stats_nameoff {
65 char name[RTE_ETH_XSTATS_NAME_SIZE];
69 static const struct latency_stats_nameoff lat_stats_strings[] = {
70 {"min_latency_ns", offsetof(struct rte_latency_stats, min_latency)},
71 {"avg_latency_ns", offsetof(struct rte_latency_stats, avg_latency)},
72 {"max_latency_ns", offsetof(struct rte_latency_stats, max_latency)},
73 {"jitter_ns", offsetof(struct rte_latency_stats, jitter)},
76 #define NUM_LATENCY_STATS (sizeof(lat_stats_strings) / \
77 sizeof(lat_stats_strings[0]))
80 rte_latencystats_update(void)
83 float *stats_ptr = NULL;
84 uint64_t values[NUM_LATENCY_STATS] = {0};
87 for (i = 0; i < NUM_LATENCY_STATS; i++) {
88 stats_ptr = RTE_PTR_ADD(glob_stats,
89 lat_stats_strings[i].offset);
90 values[i] = (uint64_t)floor((*stats_ptr)/
91 latencystat_cycles_per_ns());
94 ret = rte_metrics_update_values(RTE_METRICS_GLOBAL,
96 values, NUM_LATENCY_STATS);
98 RTE_LOG(INFO, LATENCY_STATS, "Failed to push the stats\n");
104 rte_latencystats_fill_values(struct rte_metric_value *values)
107 float *stats_ptr = NULL;
109 for (i = 0; i < NUM_LATENCY_STATS; i++) {
110 stats_ptr = RTE_PTR_ADD(glob_stats,
111 lat_stats_strings[i].offset);
113 values[i].value = (uint64_t)floor((*stats_ptr)/
114 latencystat_cycles_per_ns());
119 add_time_stamps(uint16_t pid __rte_unused,
120 uint16_t qid __rte_unused,
121 struct rte_mbuf **pkts,
123 uint16_t max_pkts __rte_unused,
124 void *user_cb __rte_unused)
127 uint64_t diff_tsc, now;
130 * For every sample interval,
131 * time stamp is marked on one received packet.
134 for (i = 0; i < nb_pkts; i++) {
135 diff_tsc = now - prev_tsc;
136 timer_tsc += diff_tsc;
138 if ((pkts[i]->ol_flags & timestamp_dynflag) == 0
139 && (timer_tsc >= samp_intvl)) {
140 *timestamp_dynfield(pkts[i]) = now;
141 pkts[i]->ol_flags |= timestamp_dynflag;
152 calc_latency(uint16_t pid __rte_unused,
153 uint16_t qid __rte_unused,
154 struct rte_mbuf **pkts,
156 void *_ __rte_unused)
158 unsigned int i, cnt = 0;
160 float latency[nb_pkts];
161 static float prev_latency;
163 * Alpha represents degree of weighting decrease in EWMA,
164 * a constant smoothing factor between 0 and 1. The value
165 * is used below for measuring average latency.
167 const float alpha = 0.2;
170 for (i = 0; i < nb_pkts; i++) {
171 if (pkts[i]->ol_flags & timestamp_dynflag)
172 latency[cnt++] = now - *timestamp_dynfield(pkts[i]);
175 rte_spinlock_lock(&glob_stats->lock);
176 for (i = 0; i < cnt; i++) {
178 * The jitter is calculated as statistical mean of interpacket
179 * delay variation. The "jitter estimate" is computed by taking
180 * the absolute values of the ipdv sequence and applying an
181 * exponential filter with parameter 1/16 to generate the
182 * estimate. i.e J=J+(|D(i-1,i)|-J)/16. Where J is jitter,
183 * D(i-1,i) is difference in latency of two consecutive packets
185 * Reference: Calculated as per RFC 5481, sec 4.1,
186 * RFC 3393 sec 4.5, RFC 1889 sec.
188 glob_stats->jitter += (fabsf(prev_latency - latency[i])
189 - glob_stats->jitter)/16;
190 if (glob_stats->min_latency == 0)
191 glob_stats->min_latency = latency[i];
192 else if (latency[i] < glob_stats->min_latency)
193 glob_stats->min_latency = latency[i];
194 else if (latency[i] > glob_stats->max_latency)
195 glob_stats->max_latency = latency[i];
197 * The average latency is measured using exponential moving
198 * average, i.e. using EWMA
199 * https://en.wikipedia.org/wiki/Moving_average
201 glob_stats->avg_latency +=
202 alpha * (latency[i] - glob_stats->avg_latency);
203 prev_latency = latency[i];
205 rte_spinlock_unlock(&glob_stats->lock);
211 rte_latencystats_init(uint64_t app_samp_intvl,
212 rte_latency_stats_flow_type_fn user_cb)
217 struct rxtx_cbs *cbs = NULL;
218 const char *ptr_strings[NUM_LATENCY_STATS] = {0};
219 const struct rte_memzone *mz = NULL;
220 const unsigned int flags = 0;
223 if (rte_memzone_lookup(MZ_RTE_LATENCY_STATS))
226 /** Allocate stats in shared memory fo multi process support */
227 mz = rte_memzone_reserve(MZ_RTE_LATENCY_STATS, sizeof(*glob_stats),
228 rte_socket_id(), flags);
230 RTE_LOG(ERR, LATENCY_STATS, "Cannot reserve memory: %s:%d\n",
235 glob_stats = mz->addr;
236 rte_spinlock_init(&glob_stats->lock);
237 samp_intvl = app_samp_intvl * latencystat_cycles_per_ns();
239 /** Register latency stats with stats library */
240 for (i = 0; i < NUM_LATENCY_STATS; i++)
241 ptr_strings[i] = lat_stats_strings[i].name;
243 latency_stats_index = rte_metrics_reg_names(ptr_strings,
245 if (latency_stats_index < 0) {
246 RTE_LOG(DEBUG, LATENCY_STATS,
247 "Failed to register latency stats names\n");
251 /* Register mbuf field and flag for Rx timestamp */
252 ret = rte_mbuf_dyn_rx_timestamp_register(×tamp_dynfield_offset,
255 RTE_LOG(ERR, LATENCY_STATS,
256 "Cannot register mbuf field/flag for timestamp\n");
260 /** Register Rx/Tx callbacks */
261 RTE_ETH_FOREACH_DEV(pid) {
262 struct rte_eth_dev_info dev_info;
264 ret = rte_eth_dev_info_get(pid, &dev_info);
266 RTE_LOG(INFO, LATENCY_STATS,
267 "Error during getting device (port %u) info: %s\n",
268 pid, strerror(-ret));
273 for (qid = 0; qid < dev_info.nb_rx_queues; qid++) {
274 cbs = &rx_cbs[pid][qid];
275 cbs->cb = rte_eth_add_first_rx_callback(pid, qid,
276 add_time_stamps, user_cb);
278 RTE_LOG(INFO, LATENCY_STATS, "Failed to "
279 "register Rx callback for pid=%d, "
280 "qid=%d\n", pid, qid);
282 for (qid = 0; qid < dev_info.nb_tx_queues; qid++) {
283 cbs = &tx_cbs[pid][qid];
284 cbs->cb = rte_eth_add_tx_callback(pid, qid,
285 calc_latency, user_cb);
287 RTE_LOG(INFO, LATENCY_STATS, "Failed to "
288 "register Tx callback for pid=%d, "
289 "qid=%d\n", pid, qid);
296 rte_latencystats_uninit(void)
301 struct rxtx_cbs *cbs = NULL;
302 const struct rte_memzone *mz = NULL;
304 /** De register Rx/Tx callbacks */
305 RTE_ETH_FOREACH_DEV(pid) {
306 struct rte_eth_dev_info dev_info;
308 ret = rte_eth_dev_info_get(pid, &dev_info);
310 RTE_LOG(INFO, LATENCY_STATS,
311 "Error during getting device (port %u) info: %s\n",
312 pid, strerror(-ret));
317 for (qid = 0; qid < dev_info.nb_rx_queues; qid++) {
318 cbs = &rx_cbs[pid][qid];
319 ret = rte_eth_remove_rx_callback(pid, qid, cbs->cb);
321 RTE_LOG(INFO, LATENCY_STATS, "failed to "
322 "remove Rx callback for pid=%d, "
323 "qid=%d\n", pid, qid);
325 for (qid = 0; qid < dev_info.nb_tx_queues; qid++) {
326 cbs = &tx_cbs[pid][qid];
327 ret = rte_eth_remove_tx_callback(pid, qid, cbs->cb);
329 RTE_LOG(INFO, LATENCY_STATS, "failed to "
330 "remove Tx callback for pid=%d, "
331 "qid=%d\n", pid, qid);
335 /* free up the memzone */
336 mz = rte_memzone_lookup(MZ_RTE_LATENCY_STATS);
338 rte_memzone_free(mz);
344 rte_latencystats_get_names(struct rte_metric_name *names, uint16_t size)
348 if (names == NULL || size < NUM_LATENCY_STATS)
349 return NUM_LATENCY_STATS;
351 for (i = 0; i < NUM_LATENCY_STATS; i++)
352 strlcpy(names[i].name, lat_stats_strings[i].name,
353 sizeof(names[i].name));
355 return NUM_LATENCY_STATS;
359 rte_latencystats_get(struct rte_metric_value *values, uint16_t size)
361 if (size < NUM_LATENCY_STATS || values == NULL)
362 return NUM_LATENCY_STATS;
364 if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
365 const struct rte_memzone *mz;
366 mz = rte_memzone_lookup(MZ_RTE_LATENCY_STATS);
368 RTE_LOG(ERR, LATENCY_STATS,
369 "Latency stats memzone not found\n");
372 glob_stats = mz->addr;
375 /* Retrieve latency stats */
376 rte_latencystats_fill_values(values);
378 return NUM_LATENCY_STATS;