On Wed, Jul 18, 2018 at 11:13:37AM -0700, Jakub Kicinski wrote:
> On Wed, 18 Jul 2018 11:33:22 +0200, Daniel Borkmann wrote:
> > On 07/18/2018 10:42 AM, Daniel Borkmann wrote:
> > > On 07/18/2018 02:27 AM, Jakub Kicinski wrote:
> > >> On Wed, 18 Jul 2018 01:31:22 +0200, Daniel Borkmann wrote:
> > >>> # bpftool map dump id 386
> > >>> [{
> > >>> "key": 0,
> > >>> "value": {
> > >>> "": {
> > >>> "value": 0,
> > >>> "ifindex": 0,
> > >>> "mac": []
> > >>> }
> > >>> }
> > >>> },{
> > >>> "key": 1,
> > >>> "value": {
> > >>> "": {
> > >>> "value": 0,
> > >>> "ifindex": 0,
> > >>> "mac": []
> > >>> }
> > >>> }
> > >>> },{
> > >>> [...]
> > >>
> > >> Ugh, the empty keys ("") look worrying, we should probably improve
> > >> handling of anonymous structs in bpftool :S
> > >
> > > Yeah agree, I think it would be nice to see a more pahole style dump
> > > where we have types and member names along with the value as otherwise
> > > it might be a bit confusing.
> >
> > Another feature that would be super useful imho would be in the /single/
> > map view e.g. 'bpftool map show id 123' to have a detailed BTF key+value
> > type dump, so in addition to the basic map info we show pahole like info
> > of the structs with length/offsets.
>
> That sounds good! We could also consider adding a btf object and
> commands to interrogate BTF types in the kernel in general.. Perhaps
> then we could add something like bpftool btf describe map id 123.
+1 on the btf subcommand.
>
> Having the single map view show more information seems interesting, but
> I wonder if it could be surprising. Is there precedent for such
> behaviour?
Having everything in one page (map show id 123) could be interesting.
One thing is the pahole-like output may be quite long?
e.g. the member of a struct could itself be another struct.
Not sure how the pahole-like output may look like in json though.
