Messages in this thread | | | From | Namhyung Kim <> | Date | Wed, 6 Jul 2022 14:27:08 -0700 | Subject | Re: [PATCH] perf inject: Add a command line option to specify build ids. |
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Hi Raul,
On Wed, Jun 29, 2022 at 5:18 PM Raul Silvera <rsilvera@google.com> 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 # Create perf.data file > $ perf record --no-buildid ls /tmp -o perf.data.no-buildid > $ 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
You'd better indent the block for the readability and to prevent possible interference from the shell (for comments usually).
The last line is a continuation from the above line and it used to print other prompts like ">".
> > Signed-off-by: Raul Silvera <rsilvera@google.com> > --- > tools/perf/builtin-inject.c | 57 +++++++++++++++++++++++++++++++++++++ > 1 file changed, 57 insertions(+) > > diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c > index a75bf11585b5..667b942f870e 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; > + struct strlist *known_build_ids; > }; > > struct event_entry { > @@ -570,9 +574,43 @@ 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 *space; > + > + pos->s = skip_spaces(pos->s); > + space = strstr(pos->s, " "); > + if (space == NULL || > + !strcmp(dso->long_name, skip_spaces(space))) > + continue; > + bid_len = space - pos->s; > + if (bid_len == 0 || bid_len / 2 > BUILD_ID_SIZE)
I'm not sure how bid_len can be 0. And you can compare to SBUILD_ID_SIZE (without dividing by 2) - but it'd be ">=". Also it could be worthwhile to check if bid_len is even.
> + return false; > + for (int ix = 0; 2 * ix + 1 < bid_len; ++ix) { > + if (!isxdigit(pos->s[2 * ix]) || > + !isxdigit(pos->s[2 * ix + 1])) > + return false; > + > + dso->bid.data[ix] = (hex(pos->s[2 * ix]) << 4 | > + hex(pos->s[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 +618,10 @@ 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 +1124,9 @@ 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 +1260,18 @@ 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; > + > + 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;
You need to release it after use. Note that strlist__delete() accepts a NULL pointer.
Thanks, Namhyung
> + } > } > > if (inject.sched_stat) { > -- > 2.37.0.rc0.161.g10f37bed90-goog >
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