sample_summary_print() uses accumulated period to calculate and display
per-sec averages. This period gets incremented by sampling interval each
time a new sample is formed, and thus equals to the number of samples
collected multiplied by this interval.
However, the totals are being calculated differently, they receive current
sample statistics already divided by the interval gotten as a difference
between sample timestamps for better precision -- in other words, they are
being incremented by the per-sec values each sample.
This leads to the excessive division of summary per-secs when interval != 1
sec. It is obvious pps couldn't become two times lower just from picking a
different sampling interval value:
$ samples/bpf/xdp_redirect_cpu -p xdp_prognum_n1_inverse_qnum -c all
-s -d 6 -i 1
< snip >
Packets received : 2,197,230,321
Average packets/s : 22,887,816
Packets redirected : 2,197,230,472
Average redir/s : 22,887,817
$ samples/bpf/xdp_redirect_cpu -p xdp_prognum_n1_inverse_qnum -c all
-s -d 6 -i 2
< snip >
Packets received : 159,566,498
Average packets/s : 11,397,607
Packets redirected : 159,566,995
Average redir/s : 11,397,642
This can be easily fixed by treating the divisor not as a period, but rather
as a total number of samples, and thus incrementing it by 1 instead of
interval. As a nice side effect, we can now remove so-named argument from a
couple of functions. Let us also create an "alias" for sample_output::rx_cnt::pps
named 'num' using a union since this field is used to store this number (period
previously) as well, and the resulting counter-intuitive code might've been a
reason for this bug.
Fixes: 156f886cf6 ("samples: bpf: Add basic infrastructure for XDP samples")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20211111215703.690-1-alexandr.lobakin@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Use the libbpf skeleton facility and other utilities provided by XDP
samples helper. Also adapt to change of type of mac address map, so that
no resizing is required.
Add a new flag for sample mask that skips priting the
from_device->to_device heading for each line, as xdp_redirect_map_multi
may have two devices but the flow of data may be bidirectional, so the
output would be confusing.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-23-memxor@gmail.com
This adds support for retrieval and printing for devmap_xmit total and
mutli mode tracepoint. For multi mode, we keep a hash map entry for each
redirection stream, such that we can dynamically add and remove entries
on output.
The from_match and to_match will be set by individual samples when
setting up the XDP program on these devices.
The multi mode tracepoint is also handy for xdp_redirect_map_multi,
where up to 32 devices can be specified.
Also add samples_init_pre_load macro to finally set up the resized maps
and mmap them in place for low overhead stats retrieval.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-12-memxor@gmail.com
This consolidates retrieval and printing into the XDP sample helper. For
the kthread stats, it expands xdp_stats separately with its own per-CPU
stats. For cpumap enqueue, we display FROM->TO stats also with its
per-CPU stats.
The help out explains in detail the various aspects of the output.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-10-memxor@gmail.com
This implements per-errno reporting (for the ones we explicitly
recognize), adds some help output, and implements the stats retrieval
and printing functions.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-6-memxor@gmail.com
This file implements some common helpers to consolidate differences in
features and functionality between the various XDP samples and give them
a consistent look, feel, and reporting capabilities.
This commit only adds support for receive statistics, which does not
rely on any tracepoint, but on the XDP program installed on the device
by each XDP redirect sample.
Some of the key features are:
* A concise output format accompanied by helpful text explaining its
fields.
* An elaborate output format building upon the concise one, and folding
out details in case of errors and staying out of view otherwise.
* Printing driver names for devices redirecting packets.
* Getting mac address for interface.
* Printing summarized total statistics for the entire session.
* Ability to dynamically switch between concise and verbose mode, using
SIGQUIT (Ctrl + \).
In later patches, the support will be extended for each tracepoint with
its own custom output in concise and verbose mode.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-4-memxor@gmail.com
Alexander Lobakin