netdev - Re: [PATCH net-next 7/7] samples/bpf: xdp_monitor tool based on tracepoints

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Date:   Tue, 29 Aug 2017 19:24:38 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Jesper Dangaard Brouer <brouer@...hat.com>
CC:     netdev@...r.kernel.org, John Fastabend <john.fastabend@...il.com>
Subject: Re: [PATCH net-next 7/7] samples/bpf: xdp_monitor tool based on tracepoints

On 08/29/2017 07:05 PM, Alexei Starovoitov wrote:
> On Tue, Aug 29, 2017 at 04:38:11PM +0200, Jesper Dangaard Brouer wrote:
>> This tool xdp_monitor demonstrate how to use the different xdp_redirect
>> tracepoints xdp_redirect{,_map}{,_err} from a BPF program.
>>
>> The default mode is to only monitor the error counters, to avoid
>> affecting the per packet performance. Tracepoints comes with a base
>> overhead of 25 nanosec for an attached bpf_prog, and 48 nanosec for
>> using a full perf record (with non-matching filter).  Thus, default
>> loading the --stats mode could affect the maximum performance.
>>
>> This version of the tool is very simple and count all types of errors
>> as one.  It will be natural to extend this later with the different
>> types of errors that can occur, which should help users quickly
>> identify common mistakes.
>>
>> Because the TP_STRUCT was kept in sync all the tracepoints loads the
>> same BPF code.  It would also be natural to extend the map version to
>> demonstrate how the map information could be used.
>>
>> Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>
>
> Nice. Did you consider using libbbpf (instead of old bpf_load.c hack)
> and make full standalone tool out of it? Looks very useful.

+1 also my suggestion. ;)

> Acked-by: Alexei Starovoitov <ast@...nel.org>