Re: perf BPF/elfdep intermitent build problems

[Wangnan (F)]

On 2015/11/19 9:24, Wangnan (F) wrote:
> On 2015/11/19 6:44, Arnaldo Carvalho de Melo wrote:
> > Have you guys ever saw this?
> >
> > [acme@zoo linux]$ alias m
> > alias m='perf stat -e cycles make O=/tmp/build/perf -C tools/perf
> > install-bin'
> > [acme @zoo linux]$ m
> > make: Entering directory '/home/git/linux/tools/perf'
> >    BUILD:   Doing 'make -j4' parallel build
> > make[2]: Nothing to be done for 'fixdep'.
> >    CC       /tmp/build/perf/util/machine.o
> >    LD       /tmp/build/perf/util/libperf-in.o
> > No libelf found
> > BPF API too old
>
> This error message means the kernel header in rootfs is too old,
> causes tools/build/feature/test-bpf.c failed to be built.

Strange... even in feature detection it should check BPF API through
kernel source where you are using to build perf...

I guess you are not using NFS or share it with other people?

> > Makefile:191: recipe for target 'elfdep' failed
> > make[2]: *** [elfdep] Error 255
> > make[2]: *** Waiting for unfinished jobs....
> > Makefile:194: recipe for target 'bpfdep' failed
> > make[2]: *** [bpfdep] Error 255
> > Makefile.perf:434: recipe for target '/tmp/build/perf/libbpf.a' failed
> > make[1]: *** [/tmp/build/perf/libbpf.a] Error 2
> > make[1]: *** Waiting for unfinished jobs....
> >    LD       /tmp/build/perf/libperf-in.o
> > Makefile:87: recipe for target 'install-bin' failed
> > make: *** [install-bin] Error 2
> > make: Leaving directory '/home/git/linux/tools/perf'
> >
> >   Performance counter stats for 'make O=/tmp/build/perf -C tools/perf
> > install-bin':
> >
> >      10,265,920,369      cycles
> >
> >         3.002799545 seconds time elapsed
> >
> > [acme@zoo linux]$
> >
> >
> > If I go and try doing a clean on the libbpf dir I see another problem:
> >
> > [acme@zoo linux]$ cd tools/lib/bpf
> > [acme@zoo bpf]$ make clean
> >
> > Auto-detecting system features:
> > ...                        libelf: [ OFF ]
> > ...                           bpf: [ OFF ]
> >
> >    CLEAN    libbpf
> >    CLEAN    core-gen
> > [acme@zoo bpf]$
> >
> > No need for feature detection when doing a plain 'make clean', right?

Right. It should be

$ cd tools/lib/bpf
$ make clean
  CLEAN    libbpf
  CLEAN    core-gen
$


After cleaning can you trigger this problem again?

> > But then, after cleaning it again, and entering tools/perf to do a 'make
> > clean' as well, it does the feature detection at a second 'make clean'
> > and this time it shoes [ on ] for both libelf and bpf, and this time
> > I manage to build perf.
> >
> > This is all intermitent, will eventually try to drill down if you don't
> > fix it first
>
> First let me try to trigger it in my environment...
>
> Thank you.
>
> > - Arnaldo
>
>
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