xdp-monitor - Man Page
a simple BPF-powered XDP monitoring tool
Synopsis
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 eventBugs
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.