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eBPF Sync

Plugin: ebpf.plugin Module: sync


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


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.


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 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.


mem.file_syncfsync, fdatasynccalls/s
mem.syncsync, syncfscalls/s


The following alerts are available:

Alert nameOn metricDescription
sync_freq mem.syncnumber of sync() system calls. Every call causes all pending modifications to filesystem metadata and cached file data to be written to the underlying filesystems.



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 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).



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.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config ebpf.d/sync.conf


This configuration file have two different sections. The [global] overwrites all default options, while [syscalls] allow user to select the syscall to monitor.

Config options
update everyData collection frequency.5no
ebpf load modeDefine whether plugin will monitor the call (entry) for the functions or it will also monitor the return (return).entryno
appsEnable or disable integration with apps.pluginnono
cgroupsEnable or disable integration with cgroup.pluginnono
pid table sizeNumber of elements stored inside hash tables used to monitor calls per PID.32768no
ebpf type formatDefine 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).autono
ebpf co-re tracingSelect 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).trampolineno
maps per coreDefine how plugin will load their hash maps. When enabled (yes) plugin will load one hash table per core, instead to have centralized information.yesno
lifetimeSet default lifetime for thread when enabled by cloud.300no
syncEnable or disable monitoring for syscall syncyesno
msyncEnable or disable monitoring for syscall msyncyesno
fsyncEnable or disable monitoring for syscall fsyncyesno
fdatasyncEnable or disable monitoring for syscall fdatasyncyesno
syncfsEnable or disable monitoring for syscall syncfsyesno
sync_file_rangeEnable or disable monitoring for syscall sync_file_rangeyesno


There are no configuration examples.

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