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From: Ian Rogers <irogers@google.com>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Andi Kleen <ak@linux.intel.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 08/35] perf buildid-cache: Add guestmount'd files to the build ID cache
Date: Tue, 19 Jul 2022 10:41:46 -0700	[thread overview]
Message-ID: <CAP-5=fUF_feSL-+=LQpg=6cRd_nXTWKCM4zU1k8TP-6veP26Rw@mail.gmail.com> (raw)
In-Reply-To: <20220711093218.10967-9-adrian.hunter@intel.com>

On Mon, Jul 11, 2022 at 2:33 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> When the guestmount option is used, a guest machine's file system mount
> point is recorded in machine->root_dir.
>
> perf already iterates guest machines when adding files to the build ID
> cache, but does not take machine->root_dir into account.
>
> Use machine->root_dir to find files for guest build IDs, and add them to
> the build ID cache using the "proper" name i.e. relative to the guest root
> directory not the host root directory.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>

Is it plausible to add a test for this? Our tests create workload but
there's no existing hypervisor way to do this. Perhaps the test can
run in a hypervisor? Or maybe there's a route that doesn't involve
hypervisors.

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/util/build-id.c | 67 +++++++++++++++++++++++++++++---------
>  tools/perf/util/build-id.h | 16 ++++++---
>  2 files changed, 63 insertions(+), 20 deletions(-)
>
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index 4c9093b64d1f..7c9f441936ee 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -625,9 +625,12 @@ static int build_id_cache__add_sdt_cache(const char *sbuild_id,
>  #endif
>
>  static char *build_id_cache__find_debug(const char *sbuild_id,
> -                                       struct nsinfo *nsi)
> +                                       struct nsinfo *nsi,
> +                                       const char *root_dir)
>  {
> +       const char *dirname = "/usr/lib/debug/.build-id/";
>         char *realname = NULL;
> +       char dirbuf[PATH_MAX];
>         char *debugfile;
>         struct nscookie nsc;
>         size_t len = 0;
> @@ -636,8 +639,12 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
>         if (!debugfile)
>                 goto out;
>
> -       len = __symbol__join_symfs(debugfile, PATH_MAX,
> -                                  "/usr/lib/debug/.build-id/");
> +       if (root_dir) {
> +               path__join(dirbuf, PATH_MAX, root_dir, dirname);
> +               dirname = dirbuf;
> +       }
> +
> +       len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);
>         snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
>                  sbuild_id + 2);
>
> @@ -668,14 +675,18 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
>
>  int
>  build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
> -                   struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
> +                   struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
> +                   const char *proper_name, const char *root_dir)
>  {
>         const size_t size = PATH_MAX;
>         char *filename = NULL, *dir_name = NULL, *linkname = zalloc(size), *tmp;
>         char *debugfile = NULL;
>         int err = -1;
>
> -       dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
> +       if (!proper_name)
> +               proper_name = name;
> +
> +       dir_name = build_id_cache__cachedir(sbuild_id, proper_name, nsi, is_kallsyms,
>                                             is_vdso);
>         if (!dir_name)
>                 goto out_free;
> @@ -715,7 +726,7 @@ build_id_cache__add(const char *sbuild_id, const char *name, const char *realnam
>          */
>         if (!is_kallsyms && !is_vdso &&
>             strncmp(".ko", name + strlen(name) - 3, 3)) {
> -               debugfile = build_id_cache__find_debug(sbuild_id, nsi);
> +               debugfile = build_id_cache__find_debug(sbuild_id, nsi, root_dir);
>                 if (debugfile) {
>                         zfree(&filename);
>                         if (asprintf(&filename, "%s/%s", dir_name,
> @@ -781,8 +792,9 @@ build_id_cache__add(const char *sbuild_id, const char *name, const char *realnam
>         return err;
>  }
>
> -int build_id_cache__add_s(const char *sbuild_id, const char *name,
> -                         struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
> +int __build_id_cache__add_s(const char *sbuild_id, const char *name,
> +                           struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
> +                           const char *proper_name, const char *root_dir)
>  {
>         char *realname = NULL;
>         int err = -1;
> @@ -796,8 +808,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
>                         goto out_free;
>         }
>
> -       err = build_id_cache__add(sbuild_id, name, realname, nsi, is_kallsyms, is_vdso);
> -
> +       err = build_id_cache__add(sbuild_id, name, realname, nsi,
> +                                 is_kallsyms, is_vdso, proper_name, root_dir);
>  out_free:
>         if (!is_kallsyms)
>                 free(realname);
> @@ -806,14 +818,16 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
>
>  static int build_id_cache__add_b(const struct build_id *bid,
>                                  const char *name, struct nsinfo *nsi,
> -                                bool is_kallsyms, bool is_vdso)
> +                                bool is_kallsyms, bool is_vdso,
> +                                const char *proper_name,
> +                                const char *root_dir)
>  {
>         char sbuild_id[SBUILD_ID_SIZE];
>
>         build_id__sprintf(bid, sbuild_id);
>
> -       return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
> -                                    is_vdso);
> +       return __build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
> +                                      is_vdso, proper_name, root_dir);
>  }
>
>  bool build_id_cache__cached(const char *sbuild_id)
> @@ -896,6 +910,10 @@ static int dso__cache_build_id(struct dso *dso, struct machine *machine,
>         bool is_kallsyms = dso__is_kallsyms(dso);
>         bool is_vdso = dso__is_vdso(dso);
>         const char *name = dso->long_name;
> +       const char *proper_name = NULL;
> +       const char *root_dir = NULL;
> +       char *allocated_name = NULL;
> +       int ret = 0;
>
>         if (!dso->has_build_id)
>                 return 0;
> @@ -905,11 +923,28 @@ static int dso__cache_build_id(struct dso *dso, struct machine *machine,
>                 name = machine->mmap_name;
>         }
>
> +       if (!machine__is_host(machine)) {
> +               if (*machine->root_dir) {
> +                       root_dir = machine->root_dir;
> +                       ret = asprintf(&allocated_name, "%s/%s", root_dir, name);
> +                       if (ret < 0)
> +                               return ret;
> +                       proper_name = name;
> +                       name = allocated_name;
> +               } else if (is_kallsyms) {
> +                       /* Cannot get guest kallsyms */
> +                       return 0;
> +               }
> +       }
> +
>         if (!is_kallsyms && dso__build_id_mismatch(dso, name))
> -               return 0;
> +               goto out_free;
>
> -       return build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
> -                                    is_kallsyms, is_vdso);
> +       ret = build_id_cache__add_b(&dso->bid, name, dso->nsinfo,
> +                                   is_kallsyms, is_vdso, proper_name, root_dir);
> +out_free:
> +       free(allocated_name);
> +       return ret;
>  }
>
>  static int
> diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
> index c19617151670..4e3a1169379b 100644
> --- a/tools/perf/util/build-id.h
> +++ b/tools/perf/util/build-id.h
> @@ -66,10 +66,18 @@ int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
>                                    struct strlist **result);
>  bool build_id_cache__cached(const char *sbuild_id);
>  int build_id_cache__add(const char *sbuild_id, const char *name, const char *realname,
> -                       struct nsinfo *nsi, bool is_kallsyms, bool is_vdso);
> -int build_id_cache__add_s(const char *sbuild_id,
> -                         const char *name, struct nsinfo *nsi,
> -                         bool is_kallsyms, bool is_vdso);
> +                       struct nsinfo *nsi, bool is_kallsyms, bool is_vdso,
> +                       const char *proper_name, const char *root_dir);
> +int __build_id_cache__add_s(const char *sbuild_id,
> +                           const char *name, struct nsinfo *nsi,
> +                           bool is_kallsyms, bool is_vdso,
> +                           const char *proper_name, const char *root_dir);
> +static inline int build_id_cache__add_s(const char *sbuild_id,
> +                                       const char *name, struct nsinfo *nsi,
> +                                       bool is_kallsyms, bool is_vdso)
> +{
> +       return __build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms, is_vdso, NULL, NULL);
> +}
>  int build_id_cache__remove_s(const char *sbuild_id);
>
>  extern char buildid_dir[];
> --
> 2.25.1
>

  reply	other threads:[~2022-07-19 17:42 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-11  9:31 [PATCH 00/35] perf intel-pt: Add support for tracing virtual machine user space on the host Adrian Hunter
2022-07-11  9:31 ` [PATCH 01/35] perf tools: Fix dso_id inode generation comparison Adrian Hunter
2022-07-18 14:57   ` Arnaldo Carvalho de Melo
2022-07-19 10:18     ` Adrian Hunter
2022-07-19 15:13       ` Ian Rogers
2022-07-19 19:16         ` Arnaldo Carvalho de Melo
2022-07-11  9:31 ` [PATCH 02/35] perf tools: Export dsos__for_each_with_build_id() Adrian Hunter
2022-07-19 16:55   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 03/35] perf ordered_events: Add ordered_events__last_flush_time() Adrian Hunter
2022-07-19 16:56   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 04/35] perf tools: Export perf_event__process_finished_round() Adrian Hunter
2022-07-19 17:04   ` Ian Rogers
2022-08-09 11:37     ` Adrian Hunter
2022-07-11  9:31 ` [PATCH 05/35] perf tools: Factor out evsel__id_hdr_size() Adrian Hunter
2022-07-19 17:09   ` Ian Rogers
2022-08-09 11:49     ` Adrian Hunter
2022-08-09 17:07       ` Ian Rogers
2022-07-11  9:31 ` [PATCH 06/35] perf tools: Add perf_event__synthesize_id_sample() Adrian Hunter
2022-07-19 17:10   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 07/35] perf script: Add --dump-unsorted-raw-trace option Adrian Hunter
2022-07-19 17:11   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 08/35] perf buildid-cache: Add guestmount'd files to the build ID cache Adrian Hunter
2022-07-19 17:41   ` Ian Rogers [this message]
2022-08-09 12:21     ` Adrian Hunter
2022-07-11  9:31 ` [PATCH 09/35] perf buildid-cache: Do not require purge files to also be in the file system Adrian Hunter
2022-07-19 17:44   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 10/35] perf tools: Add machine_pid and vcpu to id_index Adrian Hunter
2022-07-19 17:48   ` Ian Rogers
2022-08-09 12:19     ` Adrian Hunter
2022-07-11  9:31 ` [PATCH 11/35] perf session: Create guest machines from id_index Adrian Hunter
2022-07-19 17:51   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 12/35] perf tools: Add guest_cpu to hypervisor threads Adrian Hunter
2022-07-20  0:23   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 13/35] perf tools: Add machine_pid and vcpu to perf_sample Adrian Hunter
2022-07-20  0:36   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 14/35] perf tools: Use sample->machine_pid to find guest machine Adrian Hunter
2022-07-20  0:37   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 15/35] perf script: Add machine_pid and vcpu Adrian Hunter
2022-07-20  0:39   ` Ian Rogers
2022-07-11  9:31 ` [PATCH 16/35] perf dlfilter: " Adrian Hunter
2022-07-20  0:42   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 17/35] perf auxtrace: Add machine_pid and vcpu to auxtrace_error Adrian Hunter
2022-07-20  0:43   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 18/35] perf script python: Add machine_pid and vcpu Adrian Hunter
2022-07-20  0:43   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 19/35] perf script python: intel-pt-events: " Adrian Hunter
2022-07-20  0:44   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 20/35] perf tools: Remove also guest kcore_dir with host kcore_dir Adrian Hunter
2022-07-20  0:45   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 21/35] perf tools: Make has_kcore_dir() work also for guest kcore_dir Adrian Hunter
2022-07-20  0:49   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 22/35] perf tools: Automatically use guest kcore_dir if present Adrian Hunter
2022-07-20  0:51   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 23/35] perf tools: Add reallocarray_as_needed() Adrian Hunter
2022-07-20  0:55   ` Ian Rogers
2022-08-09 16:48     ` Adrian Hunter
2022-07-11  9:32 ` [PATCH 24/35] perf inject: Add support for injecting guest sideband events Adrian Hunter
2022-07-20  1:06   ` Ian Rogers
2022-08-11 17:19     ` Adrian Hunter
2022-07-11  9:32 ` [PATCH 25/35] perf machine: Use realloc_array_as_needed() in machine__set_current_tid() Adrian Hunter
2022-07-11  9:32 ` [PATCH 26/35] perf tools: Handle injected guest kernel mmap event Adrian Hunter
2022-07-20  1:09   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 27/35] perf tools: Add perf_event__is_guest() Adrian Hunter
2022-07-20  1:11   ` Ian Rogers
2022-07-20 14:06     ` Arnaldo Carvalho de Melo
2022-07-20 14:56       ` Ian Rogers
2022-07-11  9:32 ` [PATCH 28/35] perf intel-pt: Remove guest_machine_pid Adrian Hunter
2022-07-20  1:12   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 29/35] perf intel-pt: Add some more logging to intel_pt_walk_next_insn() Adrian Hunter
2022-07-20  1:13   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 30/35] perf intel-pt: Track guest context switches Adrian Hunter
2022-07-20  1:13   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 31/35] perf intel-pt: Disable sync switch with guest sideband Adrian Hunter
2022-07-20  1:14   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 32/35] perf intel-pt: Determine guest thread from " Adrian Hunter
2022-07-20  1:15   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 33/35] perf intel-pt: Add machine_pid and vcpu to auxtrace_error Adrian Hunter
2022-07-20  5:27   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 34/35] perf intel-pt: Use guest pid/tid etc in guest samples Adrian Hunter
2022-07-20  5:28   ` Ian Rogers
2022-07-11  9:32 ` [PATCH 35/35] perf intel-pt: Add documentation for tracing guest machine user space Adrian Hunter
2022-07-20  5:29   ` Ian Rogers
2022-07-18 15:28 ` [PATCH 00/35] perf intel-pt: Add support for tracing virtual machine user space on the host Arnaldo Carvalho de Melo

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