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    SubjectRe: [PATCH 6/8] perf record: Do not save pathname in ./debug/.build-id directory for vmlinux
    Em Tue, Nov 04, 2014 at 10:14:32AM +0900, Namhyung Kim escreveu:
    > When perf record finishes a session recording, it then pre-process
    > samples in order to write build-id info from actually used DSOs.
    > During this process it'll call map__load() for kernel map, and it ends
    > up calling dso__load_vmlinux_path() which replaces dso->long_name.

    Can't we achieve the same end result without introducing yet another
    symbol_conf entry?

    I think there are way too many there, we need to remove, not add :-\

    I'll add this since it improve the end result, but if you don't beat me
    to it I'll try to remove this symbol_conf entry while keeping the end
    result you achieved with it.

    - Arnaldo

    > But this function checks kernel's build-id before searching vmlinux
    > path so it'll have the cryptic name which can be confusing to users IMHO.
    >
    > This patch adds a flag to skip the build-id check during record, so
    > it'll have a vmlinux path for the kernel dso->long_name.
    >
    > Before:
    > # perf record -va sleep 3
    > mmap size 528384B
    > [ perf record: Woken up 1 times to write data ]
    > [ perf record: Captured and wrote 0.196 MB perf.data (~8545 samples) ]
    > Looking at the vmlinux_path (7 entries long)
    > Using /home/namhyung/.debug/.build-id/f0/6e17aa50adf4d00b88925e03775de107611551 for symbols
    >
    > After:
    > # perf record -va sleep 3
    > mmap size 528384B
    > [ perf record: Woken up 1 times to write data ]
    > [ perf record: Captured and wrote 0.193 MB perf.data (~8432 samples) ]
    > Looking at the vmlinux_path (7 entries long)
    > Using /lib/modules/3.16.4-1-ARCH/build/vmlinux for symbols

    > Cc: Adrian Hunter <adrian.hunter@intel.com>
    > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
    > ---
    > tools/perf/builtin-record.c | 11 +++++++++++
    > tools/perf/util/symbol.c | 11 ++++++-----
    > tools/perf/util/symbol.h | 1 +
    > 3 files changed, 18 insertions(+), 5 deletions(-)
    >
    > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
    > index 5091a27e6d28..582c4da155ea 100644
    > --- a/tools/perf/builtin-record.c
    > +++ b/tools/perf/builtin-record.c
    > @@ -200,6 +200,17 @@ static int process_buildids(struct record *rec)
    > if (size == 0)
    > return 0;
    >
    > + /*
    > + * During this process, it'll load kernel map and replace the
    > + * dso->long_name to a real pathname it found. In this case
    > + * we prefer the vmlinux path like
    > + * /lib/modules/3.16.4/build/vmlinux
    > + *
    > + * rather than build-id path (in debug directory).
    > + * $HOME/.debug/.build-id/f0/6e17aa50adf4d00b88925e03775de107611551
    > + */
    > + symbol_conf.ignore_vmlinux_buildid = true;
    > +
    > return __perf_session__process_events(session, start,
    > size - start,
    > size, &build_id__mark_dso_hit_ops);
    > diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
    > index c69915c9d5bc..c24c5b83156c 100644
    > --- a/tools/perf/util/symbol.c
    > +++ b/tools/perf/util/symbol.c
    > @@ -1511,12 +1511,10 @@ int dso__load_vmlinux_path(struct dso *dso, struct map *map,
    > symbol_filter_t filter)
    > {
    > int i, err = 0;
    > - char *filename;
    > + char *filename = NULL;
    >
    > - pr_debug("Looking at the vmlinux_path (%d entries long)\n",
    > - vmlinux_path__nr_entries + 1);
    > -
    > - filename = dso__build_id_filename(dso, NULL, 0);
    > + if (!symbol_conf.ignore_vmlinux_buildid)
    > + filename = dso__build_id_filename(dso, NULL, 0);
    > if (filename != NULL) {
    > err = dso__load_vmlinux(dso, map, filename, true, filter);
    > if (err > 0)
    > @@ -1524,6 +1522,9 @@ int dso__load_vmlinux_path(struct dso *dso, struct map *map,
    > free(filename);
    > }
    >
    > + pr_debug("Looking at the vmlinux_path (%d entries long)\n",
    > + vmlinux_path__nr_entries + 1);
    > +
    > for (i = 0; i < vmlinux_path__nr_entries; ++i) {
    > err = dso__load_vmlinux(dso, map, vmlinux_path[i], false, filter);
    > if (err > 0)
    > diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
    > index eb2c19bf8d90..ded3ca7266de 100644
    > --- a/tools/perf/util/symbol.h
    > +++ b/tools/perf/util/symbol.h
    > @@ -105,6 +105,7 @@ struct symbol_conf {
    > unsigned short nr_events;
    > bool try_vmlinux_path,
    > ignore_vmlinux,
    > + ignore_vmlinux_buildid,
    > show_kernel_path,
    > use_modules,
    > sort_by_name,
    > --
    > 2.1.2


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