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diff --git a/collectors/ebpf.plugin/integrations/ebpf_sync.md b/collectors/ebpf.plugin/integrations/ebpf_sync.md new file mode 100644 index 000000000..024c3e30e --- /dev/null +++ b/collectors/ebpf.plugin/integrations/ebpf_sync.md @@ -0,0 +1,156 @@ +<!--startmeta +custom_edit_url: "https://github.com/netdata/netdata/edit/master/collectors/ebpf.plugin/integrations/ebpf_sync.md" +meta_yaml: "https://github.com/netdata/netdata/edit/master/collectors/ebpf.plugin/metadata.yaml" +sidebar_label: "eBPF Sync" +learn_status: "Published" +learn_rel_path: "Data Collection/eBPF" +message: "DO NOT EDIT THIS FILE DIRECTLY, IT IS GENERATED BY THE COLLECTOR'S metadata.yaml FILE" +endmeta--> + +# eBPF Sync + + +<img src="https://netdata.cloud/img/ebpf.jpg" width="150"/> + + +Plugin: ebpf.plugin +Module: sync + +<img src="https://img.shields.io/badge/maintained%20by-Netdata-%2300ab44" /> + +## Overview + +Monitor syscall responsible to move data from memory to storage device. + +Attach tracing (kprobe, trampoline) to internal kernel functions according options used to compile kernel. + +This collector is only supported on the following platforms: + +- Linux + +This collector supports collecting metrics from multiple instances of this integration, including remote instances. + +The plugin needs setuid because it loads data inside kernel. Netada sets necessary permission during installation time. + +### Default Behavior + +#### Auto-Detection + +The plugin checks kernel compilation flags (CONFIG_KPROBES, CONFIG_BPF, CONFIG_BPF_SYSCALL, CONFIG_BPF_JIT, CONFIG_HAVE_SYSCALL_TRACEPOINTS), files inside debugfs, and presence of BTF files to decide which eBPF program will be attached. + +#### Limits + +The default configuration for this integration does not impose any limits on data collection. + +#### Performance Impact + +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 90-200ms per call on kernels that do not have BTF technology. + + +## Metrics + +Metrics grouped by *scope*. + +The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels. + + + +### Per eBPF Sync instance + +These metrics show total number of calls to functions inside kernel. + +This scope has no labels. + +Metrics: + +| Metric | Dimensions | Unit | +|:------|:----------|:----| +| mem.file_sync | fsync, fdatasync | calls/s | +| mem.meory_map | msync | calls/s | +| mem.sync | sync, syncfs | calls/s | +| mem.file_segment | sync_file_range | calls/s | + + + +## Alerts + + +The following alerts are available: + +| Alert name | On metric | Description | +|:------------|:----------|:------------| +| [ sync_freq ](https://github.com/netdata/netdata/blob/master/health/health.d/synchronization.conf) | mem.sync | number of sync() system calls. Every call causes all pending modifications to filesystem metadata and cached file data to be written to the underlying filesystems. | + + +## Setup + +### Prerequisites + +#### Compile kernel + +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. +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 +with different names. + +Now follow steps: +1. Copy the configuration file to /usr/src/linux/.config. +2. Select the necessary options: make oldconfig +3. Compile your kernel image: make bzImage +4. Compile your modules: make modules +5. Copy your new kernel image for boot loader directory +6. Install the new modules: make modules_install +7. Generate an initial ramdisk image (`initrd`) if it is necessary. +8. Update your boot loader + + +#### Debug Filesystem + +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`). + + + +### Configuration + +#### File + +The configuration file name for this integration is `ebpf.d/sync.conf`. + + +You can edit the configuration file using the `edit-config` script from the +Netdata [config directory](https://github.com/netdata/netdata/blob/master/docs/configure/nodes.md#the-netdata-config-directory). + +```bash +cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata +sudo ./edit-config ebpf.d/sync.conf +``` +#### Options + +This configuration file have two different sections. The `[global]` overwrites all default options, while `[syscalls]` allow user to select the syscall to monitor. + + +<details><summary>Config options</summary> + +| Name | Description | Default | Required | +|:----|:-----------|:-------|:--------:| +| update every | Data collection frequency. | 5 | False | +| ebpf load mode | Define whether plugin will monitor the call (`entry`) for the functions or it will also monitor the return (`return`). | entry | False | +| apps | Enable or disable integration with apps.plugin | no | False | +| cgroups | Enable or disable integration with cgroup.plugin | no | False | +| pid table size | Number of elements stored inside hash tables used to monitor calls per PID. | 32768 | False | +| 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 | False | +| 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 | False | +| 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 | False | +| lifetime | Set default lifetime for thread when enabled by cloud. | 300 | False | +| sync | Enable or disable monitoring for syscall `sync` | yes | False | +| msync | Enable or disable monitoring for syscall `msync` | yes | False | +| fsync | Enable or disable monitoring for syscall `fsync` | yes | False | +| fdatasync | Enable or disable monitoring for syscall `fdatasync` | yes | False | +| syncfs | Enable or disable monitoring for syscall `syncfs` | yes | False | +| sync_file_range | Enable or disable monitoring for syscall `sync_file_range` | yes | False | + +</details> + +#### Examples +There are no configuration examples. + + |