Subject: Re: [bpf-next PATCH 3/3] bpf: add sample program to trace map events

From: Jesper Dangaard Brouer <[email-masked]>
Date: Thu, 19 Apr 2018 11:20:04 +0200

On Wed, 18 Apr 2018 17:30:59 +0200
Sebastiano Miano <[email-masked]> wrote:

> This patch adds a sample program, called trace_map_events,
> that shows how to capture map events and filter them based on
> the map id.
> 
> The program accepts a list of map IDs, via the -i command line
> option, and filters all the map events related to those IDs (i.e.,
> map_create/update/lookup/next_key).
> If no IDs are specified, all map events are listed and no filtering
> is performed.
> 
> Sample usage:
> 
>  # trace_map_events -i <map_id1> -i <map_id2> -i <map_id3> ...
> 
> Signed-off-by: Sebastiano Miano <[email-masked]>

Acked-by: Jesper Dangaard Brouer <[email-masked]>

I have tested it works:

$ sudo ./trace_map_events -i 2
Init bpf_perf_event for cpu:0
Init bpf_perf_event for cpu:1
Init bpf_perf_event for cpu:2
Init bpf_perf_event for cpu:3
Init bpf_perf_event for cpu:4
Init bpf_perf_event for cpu:5
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...
LOOKUP event for map id: 2 and type: 6
Waiting for map events...

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer