xdp-monitor

xdp-monitor

XDP-monitor - a simple BPF-powered XDP monitoring tool

XDP-monitor is a tool that monitors various XDP related statistics and events using BPF tracepoints infrastructure, trying to be as low overhead as possible.

Note that by default, statistics for successful XDP redirect events is disabled, as that leads to a per-packet BPF tracing overhead, which while being low overhead, can lead to packet processing degradation.

This tool relies on the BPF raw tracepoints infrastructure in the kernel.

There is more information on the meaning of the output in both default (terse) and verbose output mode, in the Output Format Description section.

Running xdp-monitor

The syntax for running xdp-monitor is:

xdp-monitor [options]

The supported options are:

-i, –interval <SECONDS>

Set the polling interval for collecting all statistics and displaying them to the output. The unit of interval is in seconds.

-s, –stats

Enable statistics for successful redirection. This option comes with a per packet tracing overhead, for recording all successful redirections.

-e, –extended

Start xdp-bench in “extended” output mode. If not set, xdp-bench will start in “terse” mode. The output mode can be switched by hitting C-\ while the program is running. See also the Output Format Description section below.

-v, –verbose

Enable verbose logging. Supply twice to enable verbose logging from the underlying libxdp and libbpf libraries.

–version

Show the application version and exit.

-h, –help

Display a summary of the available options

Output Format Description

By default, redirect success statistics are disabled, use --stats to enable. The terse output mode is default, extended output mode can be activated using the --extended command line option.

SIGQUIT (Ctrl + \) can be used to switch the mode dynamically at runtime.

Terse mode displays at most the following fields:

rx/s		Number of packets received per second
redir/s	Number of packets successfully redirected per second
err,drop/s	Aggregated count of errors per second (including dropped packets)
xmit/s	Number of packets transmitted on the output device per second

Verbose output mode displays at most the following fields:

FIELD		  DESCRIPTION
receive	       Displays the number of packets received and errors encountered

			Whenever an error or packet drop occurs, details of per CPU error
			and drop statistics will be expanded inline in terse mode.
					pkt/s		- Packets received per second
					drop/s		- Packets dropped per second
					error/s		- Errors encountered per second
					redirect	- Displays the number of packets successfully redirected
                       Errors encountered are expanded under redirect_err field
                       Note that passing -s to enable it has a per packet overhead
					redir/s		- Packets redirected successfully per second


redirect_err	  Displays the number of packets that failed redirection

			The errno is expanded under this field with per CPU count
                       The recognized errors are:
					EINVAL:		Invalid redirection
					ENETDOWN:	Device being redirected to is down
					EMSGSIZE:	Packet length too large for device
					EOPNOTSUPP:	Operation not supported
					ENOSPC:		No space in ptr_ring of cpumap kthread

					error/s		- Packets that failed redirection per second


enqueue to cpu N Displays the number of packets enqueued to bulk queue of CPU N
                       Expands to cpu:FROM->N to display enqueue stats for each CPU enqueuing to CPU N
                       Received packets can be associated with the CPU redirect program is enqueuing
                       packets to.
					pkt/s		- Packets enqueued per second from other CPU to CPU N
					drop/s		- Packets dropped when trying to enqueue to CPU N
					bulk-avg	- Average number of packets processed for each event


kthread	       Displays the number of packets processed in CPUMAP kthread for each CPU
                       Packets consumed from ptr_ring in kthread, and its xdp_stats (after calling
                       CPUMAP bpf prog) are expanded below this. xdp_stats are expanded as a total and
                       then per-CPU to associate it to each CPU's pinned CPUMAP kthread.
					pkt/s		- Packets consumed per second from ptr_ring
					drop/s		- Packets dropped per second in kthread
					sched		- Number of times kthread called schedule()

                       xdp_stats (also expands to per-CPU counts)
					pass/s		- XDP_PASS count for CPUMAP program execution
					drop/s		- XDP_DROP count for CPUMAP program execution
					redir/s		- XDP_REDIRECT count for CPUMAP program execution


xdp_exception	  Displays xdp_exception tracepoint events

			This can occur due to internal driver errors, unrecognized
                       XDP actions and due to explicit user trigger by use of XDP_ABORTED
                       Each action is expanded below this field with its count
					hit/s		- Number of times the tracepoint was hit per second


devmap_xmit      Displays devmap_xmit tracepoint events

			This tracepoint is invoked for successful transmissions on output
                       device but these statistics are not available for generic XDP mode,
                       hence they will be omitted from the output when using SKB mode
					xmit/s		- Number of packets that were transmitted per second
					drop/s		- Number of packets that failed transmissions per second
					drv_err/s	- Number of internal driver errors per second
					bulk-avg	- Average number of packets processed for each event

BUGS

Please report any bugs on Github: https://github.com/xdp-project/xdp-tools/issues

AUTHOR

The original xdp-monitor tool was written by Jesper Dangaard Brouer. It was then rewritten to support more features by Kumar Kartikeya Dwivedi. This man page was written by Kumar Kartikeya Dwivedi.