Messages in this thread | | | Date | Wed, 29 Nov 2017 18:15:43 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: 'perf test BPF' failing, libbpf regression wrt "basic API for BPF obj name" |
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Em Wed, Nov 29, 2017 at 01:07:34PM -0800, Martin KaFai Lau escreveu: > On Tue, Nov 28, 2017 at 04:05:19PM -0300, Arnaldo Carvalho de Melo wrote: > > > > [root@jouet ~]# perf test -v bpf > > 39: BPF filter : > > 39.1: Basic BPF filtering : > > --- start --- > > test child forked, pid 12198 > > Kernel build dir is set to /lib/modules/4.14.0+/build > > set env: KBUILD_DIR=/lib/modules/4.14.0+/build > [ ... ] > > libbpf: failed to create map (name: 'flip_table'): Invalid argument > > libbpf: failed to load object '[basic_bpf_test]' > > bpf: load objects failed > 88cda1c9da02 ("bpf: libbpf: Provide basic API support to specify BPF obj name") > is introduced in 4.15.
> I think the perf@kernel-4.15 broke on older kernels like 4.14 because > the new bpf prog/map name is only introduced since 4.15.
> The newer perf needs to be compatible with an older kernel?
Sure :-)
If some ABI breaks it should detect that and adapt, and older perf tools should also gracefully fail in such a case, which I'm not sure will be the case here, haven't checked perf's BPF integration to see how it behaves in such a case, but I will.
- Arnaldo
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