On Mon, May 18, 2020 at 8:45 AM Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx> wrote: > > Em Fri, May 15, 2020 at 03:17:32PM -0700, Ian Rogers escreveu: > > Use a hashmap between a char* string and a double* value. While bpf's > > hashmap entries are size_t in size, we can't guarantee sizeof(size_t) >= > > sizeof(double). Avoid a memory allocation when gathering ids by making 0.0 > > a special value encoded as NULL. > > > > Original map suggestion by Andi Kleen: > > https://lore.kernel.org/lkml/20200224210308.GQ160988@xxxxxxxxxxxxxxxxxxxx/ > > and seconded by Jiri Olsa: > > https://lore.kernel.org/lkml/20200423112915.GH1136647@krava/ > > I'm having trouble here when building it with: > > make -C tools/perf O=/tmp/build/perf > > CC /tmp/build/perf/tests/expr.o > INSTALL trace_plugins > CC /tmp/build/perf/util/metricgroup.o > In file included from /home/acme/git/perf/tools/lib/bpf/hashmap.h:18, > from /home/acme/git/perf/tools/perf/util/expr.h:6, > from tests/expr.c:3: > /home/acme/git/perf/tools/lib/bpf/libbpf_internal.h:63: error: "pr_info" redefined [-Werror] > 63 | #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) > | > In file included from tests/expr.c:2: > /home/acme/git/perf/tools/perf/util/debug.h:24: note: this is the location of the previous definition > > It looks like libbpf's hashmap.h is being used instead of the one in > tools/perf/util/, yeah, as intended, but then since I don't have the > fixes you added to the BPF tree, the build fails, if I instead > unconditionally use > > #include "util/hashmap.h" > > It works. Please ack. > > I.e. with the patch below, further tests: > > [acme@five perf]$ perf -vv | grep -i bpf > bpf: [ on ] # HAVE_LIBBPF_SUPPORT > [acme@five perf]$ nm ~/bin/perf | grep -i libbpf_ | wc -l > 39 > [acme@five perf]$ nm ~/bin/perf | grep -i hashmap_ | wc -l > 17 > [acme@five perf]$ > > Explicitely building without LIBBPF: > > [acme@five perf]$ perf -vv | grep -i bpf > bpf: [ OFF ] # HAVE_LIBBPF_SUPPORT > [acme@five perf]$ > [acme@five perf]$ nm ~/bin/perf | grep -i libbpf_ | wc -l > 0 > [acme@five perf]$ nm ~/bin/perf | grep -i hashmap_ | wc -l > 9 > [acme@five perf]$ > > Works, > > - Arnaldo Hi Arnaldo, this build issue sounds like this patch is missing: https://lore.kernel.org/lkml/20200515221732.44078-3-irogers@xxxxxxxxxx/ The commit message there could have explicitly said having this #include causes the conflicting definitions between perf's debug.h and libbpf_internal.h's definitions of pr_info, etc. Let me know how else to help and sorry for the confusion. Thanks, Ian > diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h > index d60a8feaf50b..8a2c1074f90f 100644 > --- a/tools/perf/util/expr.h > +++ b/tools/perf/util/expr.h > @@ -2,11 +2,14 @@ > #ifndef PARSE_CTX_H > #define PARSE_CTX_H 1 > > -#ifdef HAVE_LIBBPF_SUPPORT > -#include <bpf/hashmap.h> > -#else > -#include "hashmap.h" > -#endif > +// There are fixes that need to land upstream before we can use libbpf's headers, > +// for now use our copy unconditionally, since the data structures at this point > +// are exactly the same, no problem. > +//#ifdef HAVE_LIBBPF_SUPPORT > +//#include <bpf/hashmap.h> > +//#else > +#include "util/hashmap.h" > +//#endif > > struct expr_parse_ctx { > struct hashmap ids;
