Re: [PATCH v2] perf inject: Add a command line option to specify build ids

From: Raul Silvera
Date: Fri Jul 08 2022 - 20:22:16 EST


Thank you. I just uploaded a new version addressing this feedback.

Raul E. Silvera
Software Engineer
waymo.com

On Fri, Jul 8, 2022 at 11:51 AM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> Hi Raul,
>
> On Thu, Jul 7, 2022 at 2:56 PM Raul Silvera <rsilvera@xxxxxxxxxx> wrote:
> >
> > This commit adds the option --known-build-ids to perf inject.
> > It allows the user to explicitly specify the build id for a given
> > path, instead of retrieving it from the current system. This is
> > useful in cases where a perf.data file is processed on a different
> > system from where it was collected, or if some of the binaries are
> > no longer available.
> >
> > The build ids and paths are specified in pairs in the command line.
> > Using the file:// specifier, build ids can be loaded from a file
> > directly generated by perf buildid-list. This is convenient to copy
> > build ids from one perf.data file to another.
> >
> > ** Example: In this example we use perf record to create two
> > perf.data files, one with build ids and another without, and use
> > perf buildid-list and perf inject to copy the build ids from the
> > first file to the second.
> >
> > $ perf record ls /tmp
> > $ perf record --no-buildid -o perf.data.no-buildid ls /tmp
> > $ perf buildid-list > /tmp/build-ids.txt
> > $ perf inject -b --known-build-ids='file:///tmp/build-ids.txt' \
> > -i perf.data.no-buildid -o perf.data.buildid
>
> Please add documentation for new options. Some nit pickings below.
>
> >
> > Signed-off-by: Raul Silvera <rsilvera@xxxxxxxxxx>
> > ---
> > V1 -> V2: Cleaned up patch description, deleted the strlist during
> > cleanup, and updated validation of the build id strings
> >
> > tools/perf/builtin-inject.c | 60 +++++++++++++++++++++++++++++++++++++
> > 1 file changed, 60 insertions(+)
> >
> > diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> > index a75bf11585b5..4efb992ed1a0 100644
> > --- a/tools/perf/builtin-inject.c
> > +++ b/tools/perf/builtin-inject.c
> > @@ -21,6 +21,7 @@
> > #include "util/data.h"
> > #include "util/auxtrace.h"
> > #include "util/jit.h"
> > +#include "util/string2.h"
> > #include "util/symbol.h"
> > #include "util/synthetic-events.h"
> > #include "util/thread.h"
> > @@ -35,6 +36,7 @@
> >
> > #include <linux/list.h>
> > #include <linux/string.h>
> > +#include <ctype.h>
> > #include <errno.h>
> > #include <signal.h>
> >
> > @@ -59,6 +61,8 @@ struct perf_inject {
> > struct itrace_synth_opts itrace_synth_opts;
> > char event_copy[PERF_SAMPLE_MAX_SIZE];
> > struct perf_file_section secs[HEADER_FEAT_BITS];
> > + const char *known_build_ids_source;
>
> Nit: It doesn't need to be here. You can use a local variable in
> cmd_inject for parsing.
>
>
> > + struct strlist *known_build_ids;
> > };
> >
> > struct event_entry {
> > @@ -570,9 +574,45 @@ static int dso__read_build_id(struct dso *dso)
> > return dso->has_build_id ? 0 : -1;
> > }
> >
> > +static bool perf_inject__lookup_known_build_id(struct perf_inject *inject,
> > + struct dso *dso)
> > +{
> > + struct str_node *pos;
> > + int bid_len;
> > +
> > + strlist__for_each_entry(pos, inject->known_build_ids) {
> > + const char *build_id, *dso_name;
> > +
> > + build_id = skip_spaces(pos->s);
> > + dso_name = strchr(build_id, ' ');
> > + if (dso_name == NULL)
> > + continue;
> > + bid_len = dso_name - pos->s;
> > + dso_name = skip_spaces(dso_name);
> > + if (strcmp(dso->long_name, dso_name))
> > + continue;
> > + if (bid_len % 2 != 0 || bid_len >= SBUILD_ID_SIZE)
> > + return false;
> > + for (int ix = 0; 2 * ix + 1 < bid_len; ++ix) {
> > + if (!isxdigit(build_id[2 * ix]) ||
> > + !isxdigit(build_id[2 * ix + 1]))
> > + return false;
> > +
> > + dso->bid.data[ix] = (hex(build_id[2 * ix]) << 4 |
> > + hex(build_id[2 * ix + 1]));
> > + }
> > + dso->bid.size = bid_len / 2;
> > + dso->has_build_id = 1;
> > + return true;
> > + }
> > + return false;
> > +}
> > +
> > static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
> > struct machine *machine, u8 cpumode, u32 flags)
> > {
> > + struct perf_inject *inject = container_of(tool, struct perf_inject,
> > + tool);
> > int err;
> >
> > if (is_anon_memory(dso->long_name) || flags & MAP_HUGETLB)
> > @@ -580,6 +620,10 @@ static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
> > if (is_no_dso_memory(dso->long_name))
> > return 0;
> >
> > + if (inject->known_build_ids != NULL &&
> > + perf_inject__lookup_known_build_id(inject, dso))
> > + return 1;
> > +
> > if (dso__read_build_id(dso) < 0) {
> > pr_debug("no build_id found for %s\n", dso->long_name);
> > return -1;
> > @@ -1082,6 +1126,9 @@ int cmd_inject(int argc, const char **argv)
> > "Inject build-ids into the output stream"),
> > OPT_BOOLEAN(0, "buildid-all", &inject.build_id_all,
> > "Inject build-ids of all DSOs into the output stream"),
> > + OPT_STRING(0, "known-build-ids", &inject.known_build_ids_source,
> > + "buildid path [buildid path...]",
> > + "build-ids to use for specific files"),
> > OPT_STRING('i', "input", &inject.input_name, "file",
> > "input file name"),
> > OPT_STRING('o', "output", &inject.output.path, "file",
> > @@ -1215,6 +1262,18 @@ int cmd_inject(int argc, const char **argv)
> > */
> > inject.tool.ordered_events = true;
> > inject.tool.ordering_requires_timestamps = true;
> > + if (inject.known_build_ids_source != NULL) {
> > + struct strlist *known_build_ids;
>
> Nit: I think you can use inject.known_build_ids directly.
>
> Thanks,
> Namhyung
>
>
> > +
> > + known_build_ids = strlist__new(
> > + inject.known_build_ids_source, NULL);
> > +
> > + if (known_build_ids == NULL) {
> > + pr_err("Couldn't parse known build ids.\n");
> > + goto out_delete;
> > + }
> > + inject.known_build_ids = known_build_ids;
> > + }
> > }
> >
> > if (inject.sched_stat) {
> > @@ -1241,6 +1300,7 @@ int cmd_inject(int argc, const char **argv)
> > ret = __cmd_inject(&inject);
> >
> > out_delete:
> > + strlist__delete(inject.known_build_ids);
> > zstd_fini(&(inject.session->zstd_data));
> > perf_session__delete(inject.session);
> > out_close_output:
> > --
> > 2.37.0.rc0.161.g10f37bed90-goog
> >