1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
/*
* Copyright (c) 2017 Ericsson AB.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef DPIF_NETDEV_PERF_H
#define DPIF_NETDEV_PERF_H 1
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <math.h>
#ifdef DPDK_NETDEV
#include <rte_config.h>
#include <rte_cycles.h>
#endif
#include "openvswitch/vlog.h"
#include "ovs-atomic.h"
#include "timeval.h"
#include "unixctl.h"
#include "util.h"
#ifdef __cplusplus
extern "C" {
#endif
/* This module encapsulates data structures and functions to maintain PMD
* performance metrics such as packet counters, execution cycles. It
* provides a clean API for dpif-netdev to initialize, update and read and
* reset these metrics.
*/
/* Set of counter types maintained in pmd_perf_stats. */
enum pmd_stat_type {
PMD_STAT_EXACT_HIT, /* Packets that had an exact match (emc). */
PMD_STAT_MASKED_HIT, /* Packets that matched in the flow table. */
PMD_STAT_MISS, /* Packets that did not match and upcall was ok. */
PMD_STAT_LOST, /* Packets that did not match and upcall failed. */
/* The above statistics account for the total
* number of packet passes through the datapath
* pipeline and should not be overlapping with each
* other. */
PMD_STAT_MASKED_LOOKUP, /* Number of subtable lookups for flow table
hits. Each MASKED_HIT hit will have >= 1
MASKED_LOOKUP(s). */
PMD_STAT_RECV, /* Packets entering the datapath pipeline from an
* interface. */
PMD_STAT_RECIRC, /* Packets reentering the datapath pipeline due to
* recirculation. */
PMD_STAT_SENT_PKTS, /* Packets that have been sent. */
PMD_STAT_SENT_BATCHES, /* Number of batches sent. */
PMD_CYCLES_ITER_IDLE, /* Cycles spent in idle iterations. */
PMD_CYCLES_ITER_BUSY, /* Cycles spent in busy iterations. */
PMD_N_STATS
};
/* Array of PMD counters indexed by enum pmd_stat_type.
* The n[] array contains the actual counter values since initialization
* of the PMD. Counters are atomically updated from the PMD but are
* read and cleared also from other processes. To clear the counters at
* PMD run-time, the current counter values are copied over to the zero[]
* array. To read counters we subtract zero[] value from n[]. */
struct pmd_counters {
atomic_uint64_t n[PMD_N_STATS]; /* Value since _init(). */
uint64_t zero[PMD_N_STATS]; /* Value at last _clear(). */
};
/* Container for all performance metrics of a PMD.
* Part of the struct dp_netdev_pmd_thread. */
struct pmd_perf_stats {
/* Start of the current PMD iteration in TSC cycles.*/
uint64_t start_it_tsc;
/* Latest TSC time stamp taken in PMD. */
uint64_t last_tsc;
/* If non-NULL, outermost cycle timer currently running in PMD. */
struct cycle_timer *cur_timer;
/* Set of PMD counters with their zero offsets. */
struct pmd_counters counters;
};
/* Support for accurate timing of PMD execution on TSC clock cycle level.
* These functions are intended to be invoked in the context of pmd threads. */
/* Read the TSC cycle register and cache it. Any function not requiring clock
* cycle accuracy should read the cached value using cycles_counter_get() to
* avoid the overhead of reading the TSC register. */
static inline uint64_t
cycles_counter_update(struct pmd_perf_stats *s)
{
#ifdef DPDK_NETDEV
return s->last_tsc = rte_get_tsc_cycles();
#else
return s->last_tsc = 0;
#endif
}
static inline uint64_t
cycles_counter_get(struct pmd_perf_stats *s)
{
return s->last_tsc;
}
/* A nestable timer for measuring execution time in TSC cycles.
*
* Usage:
* struct cycle_timer timer;
*
* cycle_timer_start(pmd, &timer);
* <Timed execution>
* uint64_t cycles = cycle_timer_stop(pmd, &timer);
*
* The caller must guarantee that a call to cycle_timer_start() is always
* paired with a call to cycle_stimer_stop().
*
* Is is possible to have nested cycles timers within the timed code. The
* execution time measured by the nested timers is excluded from the time
* measured by the embracing timer.
*/
struct cycle_timer {
uint64_t start;
uint64_t suspended;
struct cycle_timer *interrupted;
};
static inline void
cycle_timer_start(struct pmd_perf_stats *s,
struct cycle_timer *timer)
{
struct cycle_timer *cur_timer = s->cur_timer;
uint64_t now = cycles_counter_update(s);
if (cur_timer) {
cur_timer->suspended = now;
}
timer->interrupted = cur_timer;
timer->start = now;
timer->suspended = 0;
s->cur_timer = timer;
}
static inline uint64_t
cycle_timer_stop(struct pmd_perf_stats *s,
struct cycle_timer *timer)
{
/* Assert that this is the current cycle timer. */
ovs_assert(s->cur_timer == timer);
uint64_t now = cycles_counter_update(s);
struct cycle_timer *intr_timer = timer->interrupted;
if (intr_timer) {
/* Adjust the start offset by the suspended cycles. */
intr_timer->start += now - intr_timer->suspended;
}
/* Restore suspended timer, if any. */
s->cur_timer = intr_timer;
return now - timer->start;
}
void pmd_perf_stats_init(struct pmd_perf_stats *s);
void pmd_perf_stats_clear(struct pmd_perf_stats *s);
void pmd_perf_read_counters(struct pmd_perf_stats *s,
uint64_t stats[PMD_N_STATS]);
/* PMD performance counters are updated lock-less. For real PMDs
* they are only updated from the PMD thread itself. In the case of the
* NON-PMD they might be updated from multiple threads, but we can live
* with losing a rare update as 100% accuracy is not required.
* However, as counters are read for display from outside the PMD thread
* with e.g. pmd-stats-show, we make sure that the 64-bit read and store
* operations are atomic also on 32-bit systems so that readers cannot
* not read garbage. On 64-bit systems this incurs no overhead. */
static inline void
pmd_perf_update_counter(struct pmd_perf_stats *s,
enum pmd_stat_type counter, int delta)
{
uint64_t tmp;
atomic_read_relaxed(&s->counters.n[counter], &tmp);
tmp += delta;
atomic_store_relaxed(&s->counters.n[counter], tmp);
}
static inline void
pmd_perf_start_iteration(struct pmd_perf_stats *s)
{
if (OVS_LIKELY(s->last_tsc)) {
/* We assume here that last_tsc was updated immediately prior at
* the end of the previous iteration, or just before the first
* iteration. */
s->start_it_tsc = s->last_tsc;
} else {
/* In case last_tsc has never been set before. */
s->start_it_tsc = cycles_counter_update(s);
}
}
static inline void
pmd_perf_end_iteration(struct pmd_perf_stats *s, int rx_packets)
{
uint64_t cycles = cycles_counter_update(s) - s->start_it_tsc;
if (rx_packets > 0) {
pmd_perf_update_counter(s, PMD_CYCLES_ITER_BUSY, cycles);
} else {
pmd_perf_update_counter(s, PMD_CYCLES_ITER_IDLE, cycles);
}
}
#ifdef __cplusplus
}
#endif
#endif /* DPIF_NETDEV_PERF_H */
|
