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Message-ID: <CAM9d7cicdANoZCrqctdW+m+zx6_3nm4F_A_=5jEcBT7auOScJQ@mail.gmail.com>
Date: Wed, 10 Aug 2022 10:42:34 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Raul Silvera <rsilvera@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
linux-perf-users <linux-perf-users@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] perf inject: Add a command line option to specify
build ids.
Hello,
On Fri, Jul 8, 2022 at 5:20 PM Raul Silvera <rsilvera@...gle.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
> $ 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
>
> Signed-off-by: Raul Silvera <rsilvera@...gle.com>
> ---
>
> V2 -> V3 Added documentation and removed unnecessary temps
> V1 -> V2: Cleaned up patch description, deleted the strlist during
> cleanup, and updated validation of the build id strings
>
> tools/perf/Documentation/perf-inject.txt | 7 ++-
> tools/perf/builtin-inject.c | 57 ++++++++++++++++++++++++
> 2 files changed, 63 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/Documentation/perf-inject.txt b/tools/perf/Documentation/perf-inject.txt
> index 0570a1ccd344..78474d941fd8 100644
> --- a/tools/perf/Documentation/perf-inject.txt
> +++ b/tools/perf/Documentation/perf-inject.txt
> @@ -27,9 +27,14 @@ OPTIONS
> --build-ids::
> Inject build-ids into the output stream
>
> ---buildid-all:
> +--buildid-all::
> Inject build-ids of all DSOs into the output stream
>
> +--known-build-ids=::
> + Override build-ids to inject using these comma-separated pairs of
> + build-id and path. Understands file://filename to read these pairs
> + from a file, which can be generated with perf buildid-list.
> +
> -v::
> --verbose::
> Be more verbose.
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index a75bf11585b5..bf10c6478493 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 +61,7 @@ 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];
> + struct strlist *known_build_ids;
> };
>
> struct event_entry {
> @@ -570,9 +573,45 @@ 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;
I think this is a broken entry and it should check them when it
creates the strlist
rather than whenever it looks up the entries.
You may use strlist__for_each_entry_safe() and strlist__remove().
> + 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;
Ditto.
Thanks,
Namhyung
> +
> + 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 +619,10 @@ 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;
> @@ -1076,12 +1119,16 @@ int cmd_inject(int argc, const char **argv)
> };
> int ret;
> bool repipe = true;
> + const char *known_build_ids = NULL;
>
> struct option options[] = {
> OPT_BOOLEAN('b', "build-ids", &inject.build_ids,
> "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", &known_build_ids,
> + "buildid path [,buildid path...]",
> + "build-ids to use for given paths"),
> OPT_STRING('i', "input", &inject.input_name, "file",
> "input file name"),
> OPT_STRING('o', "output", &inject.output.path, "file",
> @@ -1215,6 +1262,15 @@ int cmd_inject(int argc, const char **argv)
> */
> inject.tool.ordered_events = true;
> inject.tool.ordering_requires_timestamps = true;
> + if (known_build_ids != NULL) {
> + inject.known_build_ids = strlist__new(
> + known_build_ids, NULL);
> +
> + if (inject.known_build_ids == NULL) {
> + pr_err("Couldn't parse known build ids.\n");
> + goto out_delete;
> + }
> + }
> }
>
> if (inject.sched_stat) {
> @@ -1241,6 +1297,7 @@ 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
>
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