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8c498935 MCC |
1 | .. SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | =============================================== | |
1da177e4 | 4 | Generic networking statistics for netlink users |
8c498935 | 5 | =============================================== |
1da177e4 LT |
6 | |
7 | Statistic counters are grouped into structs: | |
8 | ||
8c498935 | 9 | ==================== ===================== ===================== |
1da177e4 | 10 | Struct TLV type Description |
8c498935 | 11 | ==================== ===================== ===================== |
1da177e4 LT |
12 | gnet_stats_basic TCA_STATS_BASIC Basic statistics |
13 | gnet_stats_rate_est TCA_STATS_RATE_EST Rate estimator | |
14 | gnet_stats_queue TCA_STATS_QUEUE Queue statistics | |
15 | none TCA_STATS_APP Application specific | |
8c498935 | 16 | ==================== ===================== ===================== |
1da177e4 LT |
17 | |
18 | ||
19 | Collecting: | |
20 | ----------- | |
21 | ||
8c498935 MCC |
22 | Declare the statistic structs you need:: |
23 | ||
24 | struct mystruct { | |
25 | struct gnet_stats_basic bstats; | |
26 | struct gnet_stats_queue qstats; | |
27 | ... | |
28 | }; | |
29 | ||
30 | Update statistics, in dequeue() methods only, (while owning qdisc->running):: | |
1da177e4 | 31 | |
8c498935 MCC |
32 | mystruct->tstats.packet++; |
33 | mystruct->qstats.backlog += skb->pkt_len; | |
1da177e4 LT |
34 | |
35 | ||
36 | Export to userspace (Dump): | |
37 | --------------------------- | |
38 | ||
8c498935 | 39 | :: |
1da177e4 | 40 | |
8c498935 MCC |
41 | my_dumping_routine(struct sk_buff *skb, ...) |
42 | { | |
43 | struct gnet_dump dump; | |
1da177e4 | 44 | |
8c498935 MCC |
45 | if (gnet_stats_start_copy(skb, TCA_STATS2, &mystruct->lock, &dump, |
46 | TCA_PAD) < 0) | |
47 | goto rtattr_failure; | |
1da177e4 | 48 | |
8c498935 MCC |
49 | if (gnet_stats_copy_basic(&dump, &mystruct->bstats) < 0 || |
50 | gnet_stats_copy_queue(&dump, &mystruct->qstats) < 0 || | |
51 | gnet_stats_copy_app(&dump, &xstats, sizeof(xstats)) < 0) | |
52 | goto rtattr_failure; | |
53 | ||
54 | if (gnet_stats_finish_copy(&dump) < 0) | |
55 | goto rtattr_failure; | |
56 | ... | |
57 | } | |
1da177e4 LT |
58 | |
59 | TCA_STATS/TCA_XSTATS backward compatibility: | |
60 | -------------------------------------------- | |
61 | ||
62 | Prior users of struct tc_stats and xstats can maintain backward | |
63 | compatibility by calling the compat wrappers to keep providing the | |
8c498935 | 64 | existing TLV types:: |
1da177e4 | 65 | |
8c498935 MCC |
66 | my_dumping_routine(struct sk_buff *skb, ...) |
67 | { | |
68 | if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, | |
69 | TCA_XSTATS, &mystruct->lock, &dump, | |
70 | TCA_PAD) < 0) | |
71 | goto rtattr_failure; | |
72 | ... | |
73 | } | |
1da177e4 LT |
74 | |
75 | A struct tc_stats will be filled out during gnet_stats_copy_* calls | |
76 | and appended to the skb. TCA_XSTATS is provided if gnet_stats_copy_app | |
77 | was called. | |
78 | ||
79 | ||
80 | Locking: | |
81 | -------- | |
82 | ||
83 | Locks are taken before writing and released once all statistics have | |
84 | been written. Locks are always released in case of an error. You | |
85 | are responsible for making sure that the lock is initialized. | |
86 | ||
87 | ||
88 | Rate Estimator: | |
8c498935 | 89 | --------------- |
1da177e4 LT |
90 | |
91 | 0) Prepare an estimator attribute. Most likely this would be in user | |
92 | space. The value of this TLV should contain a tc_estimator structure. | |
992caacf ML |
93 | As usual, such a TLV needs to be 32 bit aligned and therefore the |
94 | length needs to be appropriately set, etc. The estimator interval | |
1da177e4 LT |
95 | and ewma log need to be converted to the appropriate values. |
96 | tc_estimator.c::tc_setup_estimator() is advisable to be used as the | |
97 | conversion routine. It does a few clever things. It takes a time | |
98 | interval in microsecs, a time constant also in microsecs and a struct | |
99 | tc_estimator to be populated. The returned tc_estimator can be | |
100 | transported to the kernel. Transfer such a structure in a TLV of type | |
101 | TCA_RATE to your code in the kernel. | |
102 | ||
103 | In the kernel when setting up: | |
8c498935 | 104 | |
1da177e4 LT |
105 | 1) make sure you have basic stats and rate stats setup first. |
106 | 2) make sure you have initialized stats lock that is used to setup such | |
107 | stats. | |
8c498935 | 108 | 3) Now initialize a new estimator:: |
1da177e4 | 109 | |
8c498935 MCC |
110 | int ret = gen_new_estimator(my_basicstats,my_rate_est_stats, |
111 | mystats_lock, attr_with_tcestimator_struct); | |
1da177e4 | 112 | |
8c498935 MCC |
113 | if ret == 0 |
114 | success | |
115 | else | |
116 | failed | |
1da177e4 | 117 | |
fff9289b ML |
118 | From now on, every time you dump my_rate_est_stats it will contain |
119 | up-to-date info. | |
1da177e4 LT |
120 | |
121 | Once you are done, call gen_kill_estimator(my_basicstats, | |
122 | my_rate_est_stats) Make sure that my_basicstats and my_rate_est_stats | |
123 | are still valid (i.e still exist) at the time of making this call. | |
124 | ||
125 | ||
126 | Authors: | |
127 | -------- | |
8c498935 MCC |
128 | - Thomas Graf <tgraf@suug.ch> |
129 | - Jamal Hadi Salim <hadi@cyberus.ca> |