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