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1 <!--startmeta
2 custom_edit_url: "https://github.com/netdata/netdata/edit/master/src/collectors/ebpf.plugin/integrations/ebpf_shm.md"
3 meta_yaml: "https://github.com/netdata/netdata/edit/master/src/collectors/ebpf.plugin/metadata.yaml"
4 sidebar_label: "eBPF SHM"
5 learn_status: "Published"
6 learn_rel_path: "Collecting Metrics/Collectors/Operating Systems"
7 keywords: ['syscall', 'shared memory', 'eBPF']
8 message: "DO NOT EDIT THIS FILE DIRECTLY, IT IS GENERATED BY THE COLLECTOR'S metadata.yaml FILE"
9 endmeta-->
10
11 # eBPF SHM
12
13
14 <img src="https://netdata.cloud/img/ebpf.jpg" width="150"/>
15
16
17 Plugin: ebpf.plugin
18 Module: shm
19
20 <img src="https://img.shields.io/badge/maintained%20by-Netdata-%2300ab44" />
21
22 ## Overview
23
24 Monitor syscall responsible to manipulate shared memory.
25
26 Attach tracing (kprobe, trampoline) to internal kernel functions according options used to compile kernel.
27
28 This collector is only supported on the following platforms:
29
30 - Linux
31
32 This collector supports collecting metrics from multiple instances of this integration, including remote instances.
33
34 The plugin needs setuid because it loads data inside kernel. Netada sets necessary permission during installation time.
35
36 eBPF SHM can be monitored further using the following other integrations:
37
38 - [Applications](/src/collectors/apps.plugin/integrations/applications.md)
39 - [Containers](/src/collectors/cgroups.plugin/integrations/containers.md)
40
41 ### Default Behavior
42
43 #### Auto-Detection
44
45 The plugin checks kernel compilation flags (CONFIG_KPROBES, CONFIG_BPF, CONFIG_BPF_SYSCALL, CONFIG_BPF_JIT) and presence of BTF files to decide which eBPF program will be attached.
46
47 #### Limits
48
49 The default configuration for this integration does not impose any limits on data collection.
50
51 #### Performance Impact
52
53 This thread will add overhead every time that an internal kernel function monitored by this thread is called. The estimated additional period of time is between 90-200ns per call on kernels that do not have BTF technology.
54
55 ## Setup
56
57
58 ### Prerequisites
59
60 #### Compile kernel
61
62 Check if your kernel was compiled with necessary options (CONFIG_KPROBES, CONFIG_BPF, CONFIG_BPF_SYSCALL, CONFIG_BPF_JIT) in `/proc/config.gz` or inside /boot/config file. Some cited names can be different accoring preferences of Linux distributions.
63 When you do not have options set, it is necessary to get the kernel source code from https://kernel.org or a kernel package from your distribution, this last is preferred. The kernel compilation has a well definedd pattern, but distributions can deliver their configuration files
64 with different names.
65
66 Now follow steps:
67 1. Copy the configuration file to /usr/src/linux/.config.
68 2. Select the necessary options: make oldconfig
69 3. Compile your kernel image: make bzImage
70 4. Compile your modules: make modules
71 5. Copy your new kernel image for boot loader directory
72 6. Install the new modules: make modules_install
73 7. Generate an initial ramdisk image (`initrd`) if it is necessary.
74 8. Update your boot loader
75
76
77 #### Debug Filesystem
78
79 This thread needs to attach a tracepoint to monitor when a process schedule an exit event. To allow this specific feaure, it is necessary to mount `debugfs` (`mount -t debugfs none /sys/kernel/debug/`).`
80
81
82
83 ### Configuration
84
85 #### Options
86
87 This configuration file have two different sections. The `[global]` overwrites all default options, while `[syscalls]` allow user to select the syscall to monitor.
88
89
90 <details open><summary>Config options</summary>
91
92
93
94 | Option | Description | Default | Required |
95 |:-----|:------------|:--------|:---------:|
96 | update every | Data collection frequency. | 10 | no |
97 | ebpf load mode | Define whether plugin will monitor the call (`entry`) for the functions or it will also monitor the return (`return`). | entry | no |
98 | apps | Enable or disable integration with apps.plugin | no | no |
99 | cgroups | Enable or disable integration with cgroup.plugin | no | no |
100 | pid table size | Number of elements stored inside hash tables used to monitor calls per PID. | 32768 | no |
101 | ebpf type format | Define the file type to load an eBPF program. Three options are available: `legacy` (Attach only `kprobe`), `co-re` (Plugin tries to use `trampoline` when available), and `auto` (plugin check OS configuration before to load). | auto | no |
102 | ebpf co-re tracing | Select the attach method used by plugin when `co-re` is defined in previous option. Two options are available: `trampoline` (Option with lowest overhead), and `probe` (the same of legacy code). | trampoline | no |
103 | maps per core | Define how plugin will load their hash maps. When enabled (`yes`) plugin will load one hash table per core, instead to have centralized information. | yes | no |
104 | lifetime | Set default lifetime for thread when enabled by cloud. | 300 | no |
105 | shmget | Enable or disable monitoring for syscall `shmget` | yes | no |
106 | shmat | Enable or disable monitoring for syscall `shmat` | yes | no |
107 | shmdt | Enable or disable monitoring for syscall `shmdt` | yes | no |
108 | shmctl | Enable or disable monitoring for syscall `shmctl` | yes | no |
109
110
111 </details>
112
113
114
115 #### via File
116
117 The configuration file name for this integration is `ebpf.d/shm.conf`.
118
119 The file format is a modified INI syntax. The general structure is:
120
121 ```ini
122 [section1]
123 option1 = some value
124 option2 = some other value
125
126 [section2]
127 option3 = some third value
128 ```
129 You can edit the configuration file using the [`edit-config`](https://github.com/netdata/netdata/blob/master/docs/netdata-agent/configuration/README.md#edit-configuration-files) script from the
130 Netdata [config directory](https://github.com/netdata/netdata/blob/master/docs/netdata-agent/configuration/README.md#locate-your-config-directory).
131
132 ```bash
133 cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
134 sudo ./edit-config ebpf.d/shm.conf
135 ```
136
137 ##### Examples
138 There are no configuration examples.
139
140
141
142 ## Alerts
143
144 There are no alerts configured by default for this integration.
145
146
147 ## Metrics
148
149 Metrics grouped by *scope*.
150
151 The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.
152
153
154
155 ### Per cgroup
156
157 These Metrics show grouped information per cgroup/service.
158
159 This scope has no labels.
160
161 Metrics:
162
163 | Metric | Dimensions | Unit |
164 |:------|:----------|:----|
165 | cgroup.shmget | get | calls/s |
166 | cgroup.shmat | at | calls/s |
167 | cgroup.shmdt | dt | calls/s |
168 | cgroup.shmctl | ctl | calls/s |
169 | services.shmget | a dimension per systemd service | calls/s |
170 | services.shmat | a dimension per systemd service | calls/s |
171 | services.shmdt | a dimension per systemd service | calls/s |
172 | services.shmctl | a dimension per systemd service | calls/s |
173
174 ### Per apps
175
176 These Metrics show grouped information per apps group.
177
178 Labels:
179
180 | Label | Description |
181 |:-----------|:----------------|
182 | app_group | The name of the group defined in the configuration. |
183
184 Metrics:
185
186 | Metric | Dimensions | Unit |
187 |:------|:----------|:----|
188 | app.ebpf_shmget_call | calls | calls/s |
189 | app.ebpf_shmat_call | calls | calls/s |
190 | app.ebpf_shmdt_call | calls | calls/s |
191 | app.ebpf_shmctl_call | calls | calls/s |
192
193 ### Per eBPF SHM instance
194
195 These Metrics show number of calls for specified syscall.
196
197 This scope has no labels.
198
199 Metrics:
200
201 | Metric | Dimensions | Unit |
202 |:------|:----------|:----|
203 | system.shared_memory_calls | get, at, dt, ctl | calls/s |
204
205