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Date: Tue, 25 Jun 2024 16:20:49 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Changbin Du <changbin.du@...wei.com>,
Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>, Nathan Chancellor <nathan@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
"Liang, Kan" <kan.liang@...ux.intel.com>,
Nick Desaulniers <ndesaulniers@...gle.com>, Bill Wendling
<morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
llvm@...ts.linux.dev
Subject: Re: [PATCH v4 1/5] perf: support specify vdso path in cmdline
On 25/06/24 06:37, Changbin Du wrote:
> The vdso dumped from process memory (in buildid-cache) lacks debugging
> info. To annotate vdso symbols with source lines we need specify a
> debugging version.
>
> For x86, we can find them from your local build as
> arch/x86/entry/vdso/vdso{32,64}.so.dbg. Or they may reside in
> /lib/modules/<version>/vdso/vdso{32,64}.so on Ubuntu. But notice that
> the buildid has to match.
>
> $ sudo perf record -a
> $ sudo perf report --objdump=llvm-objdump \
> --vdso arch/x86/entry/vdso/vdso64.so.dbg,arch/x86/entry/vdso/vdso32.so.dbg
>
> Samples: 17K of event 'cycles:P', 4000 Hz, Event count (approx.): 1760
> __vdso_clock_gettime /work/linux-host/arch/x86/entry/vdso/vdso64.so.d
> Percent│ movq -48(%rbp),%rsi
> │ testq %rax,%rax
> │ ; return vread_hvclock();
> │ movq %rax,%rdx
> │ ; if (unlikely(!vdso_cycles_ok(cycles)))
> │ ↑ js eb
> │ ↑ jmp 74
> │ ; ts->tv_sec = vdso_ts->sec;
> 0.02 │147: leaq 2(%rbx),%rax
> │ shlq $4, %rax
> │ addq %r10,%rax
> │ ; while ((seq = READ_ONCE(vd->seq)) & 1) {
> 9.38 │152: movl (%r10),%ecx
>
> When doing cross platform analysis, we also need specify the vdso path if
> we are interested in its symbols.
Would it be possible to add vdso and vdso debug to the build-id
cache and ensure perf can find it there?
Typically, getting dsos from another machine is handled via
build-id cache e.g. what perf-archive does
>
> v2: update documentation.
>
> Signed-off-by: Changbin Du <changbin.du@...wei.com>
> ---
> tools/perf/Documentation/perf-annotate.txt | 3 +
> tools/perf/Documentation/perf-c2c.txt | 3 +
> tools/perf/Documentation/perf-inject.txt | 3 +
> tools/perf/Documentation/perf-report.txt | 3 +
> tools/perf/Documentation/perf-script.txt | 3 +
> tools/perf/Documentation/perf-top.txt | 3 +
> tools/perf/builtin-annotate.c | 2 +
> tools/perf/builtin-c2c.c | 2 +
> tools/perf/builtin-inject.c | 2 +
> tools/perf/builtin-report.c | 2 +
> tools/perf/builtin-script.c | 2 +
> tools/perf/builtin-top.c | 2 +
> tools/perf/util/disasm.c | 7 +-
> tools/perf/util/symbol.c | 82 +++++++++++++++++++++-
> tools/perf/util/symbol_conf.h | 5 ++
> 15 files changed, 119 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-annotate.txt b/tools/perf/Documentation/perf-annotate.txt
> index b95524bea021..4b6692f9a793 100644
> --- a/tools/perf/Documentation/perf-annotate.txt
> +++ b/tools/perf/Documentation/perf-annotate.txt
> @@ -58,6 +58,9 @@ OPTIONS
> --ignore-vmlinux::
> Ignore vmlinux files.
>
> +--vdso=<vdso1[,vdso2]>::
> + Specify vdso pathnames. You can specify up to two for multiarch-support.
> +
> --itrace::
> Options for decoding instruction tracing data. The options are:
>
> diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt
> index 856f0dfb8e5a..7c07efca7542 100644
> --- a/tools/perf/Documentation/perf-c2c.txt
> +++ b/tools/perf/Documentation/perf-c2c.txt
> @@ -71,6 +71,9 @@ REPORT OPTIONS
> --vmlinux=<file>::
> vmlinux pathname
>
> +--vdso=<vdso1[,vdso2]>::
> + Specify vdso pathnames. You can specify up to two for multiarch-support.
> +
> -v::
> --verbose::
> Be more verbose (show counter open errors, etc).
> diff --git a/tools/perf/Documentation/perf-inject.txt b/tools/perf/Documentation/perf-inject.txt
> index c972032f4ca0..3c88967b4c7f 100644
> --- a/tools/perf/Documentation/perf-inject.txt
> +++ b/tools/perf/Documentation/perf-inject.txt
> @@ -62,6 +62,9 @@ OPTIONS
> --kallsyms=<file>::
> kallsyms pathname
>
> +--vdso=<vdso1[,vdso2]>::
> + Specify vdso pathnames. You can specify up to two for multiarch-support.
> +
> --itrace::
> Decode Instruction Tracing data, replacing it with synthesized events.
> Options are:
> diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
> index d2b1593ef700..8a3ba5f74cac 100644
> --- a/tools/perf/Documentation/perf-report.txt
> +++ b/tools/perf/Documentation/perf-report.txt
> @@ -345,6 +345,9 @@ OPTIONS
> Load module symbols. WARNING: This should only be used with -k and
> a LIVE kernel.
>
> +--vdso=<vdso1[,vdso2]>::
> + Specify vdso pathnames. You can specify up to two for multiarch-support.
> +
> -f::
> --force::
> Don't do ownership validation.
> diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
> index ff086ef05a0c..48f9974ca4c5 100644
> --- a/tools/perf/Documentation/perf-script.txt
> +++ b/tools/perf/Documentation/perf-script.txt
> @@ -296,6 +296,9 @@ OPTIONS
> --kallsyms=<file>::
> kallsyms pathname
>
> +--vdso=<vdso1[,vdso2]>::
> + Specify vdso pathnames. You can specify up to two for multiarch-support.
> +
> --symfs=<directory>::
> Look for files with symbols relative to this directory.
>
> diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt
> index a754875fa5bb..1cf3ee16a0c1 100644
> --- a/tools/perf/Documentation/perf-top.txt
> +++ b/tools/perf/Documentation/perf-top.txt
> @@ -76,6 +76,9 @@ Default is to monitor all CPUS.
> --kallsyms=<file>::
> kallsyms pathname
>
> +--vdso=<vdso1[,vdso2]>::
> + Specify vdso pathnames. You can specify up to two for multiarch-support.
> +
> -m <pages>::
> --mmap-pages=<pages>::
> Number of mmap data pages (must be a power of two) or size
> diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
> index 50d2fb222d48..ff466882065d 100644
> --- a/tools/perf/builtin-annotate.c
> +++ b/tools/perf/builtin-annotate.c
> @@ -742,6 +742,8 @@ int cmd_annotate(int argc, const char **argv)
> "file", "vmlinux pathname"),
> OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
> "load module symbols - WARNING: use only with -k and LIVE kernel"),
> + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> + parse_vdso_pathnames),
> OPT_BOOLEAN('l', "print-line", &annotate_opts.print_lines,
> "print matching source lines (may be slow)"),
> OPT_BOOLEAN('P', "full-paths", &annotate_opts.full_path,
> diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> index c157bd31f2e5..4764f9139661 100644
> --- a/tools/perf/builtin-c2c.c
> +++ b/tools/perf/builtin-c2c.c
> @@ -3018,6 +3018,8 @@ static int perf_c2c__report(int argc, const char **argv)
> const struct option options[] = {
> OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
> "file", "vmlinux pathname"),
> + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> + parse_vdso_pathnames),
> OPT_STRING('i', "input", &input_name, "file",
> "the input file to process"),
> OPT_INCR('N', "node-info", &c2c.node_info,
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index a212678d47be..e774e83d0a0f 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -2247,6 +2247,8 @@ int cmd_inject(int argc, const char **argv)
> "don't load vmlinux even if found"),
> OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name, "file",
> "kallsyms pathname"),
> + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> + parse_vdso_pathnames),
> OPT_BOOLEAN('f', "force", &data.force, "don't complain, do it"),
> OPT_CALLBACK_OPTARG(0, "itrace", &inject.itrace_synth_opts,
> NULL, "opts", "Instruction Tracing options\n"
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index 69618fb0110b..a64b48460dce 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -1324,6 +1324,8 @@ int cmd_report(int argc, const char **argv)
> "don't load vmlinux even if found"),
> OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
> "file", "kallsyms pathname"),
> + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> + parse_vdso_pathnames),
> OPT_BOOLEAN('f', "force", &symbol_conf.force, "don't complain, do it"),
> OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
> "load module symbols - WARNING: use only with -k and LIVE kernel"),
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index c16224b1fef3..2e358922a8d1 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -3965,6 +3965,8 @@ int cmd_script(int argc, const char **argv)
> "file", "vmlinux pathname"),
> OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
> "file", "kallsyms pathname"),
> + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> + parse_vdso_pathnames),
> OPT_BOOLEAN('G', "hide-call-graph", &no_callchain,
> "When printing symbols do not display call chain"),
> OPT_CALLBACK(0, "symfs", NULL, "directory",
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 1d6aef51c122..a3cce4e76eb9 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1479,6 +1479,8 @@ int cmd_top(int argc, const char **argv)
> "file", "kallsyms pathname"),
> OPT_BOOLEAN('K', "hide_kernel_symbols", &top.hide_kernel_symbols,
> "hide kernel symbols"),
> + OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
> + parse_vdso_pathnames),
> OPT_CALLBACK('m', "mmap-pages", &opts->mmap_pages, "pages",
> "number of mmap data pages", evlist__parse_mmap_pages),
> OPT_INTEGER('r', "realtime", &top.realtime_prio,
> diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
> index 72aec8f61b94..8d9d78d3150c 100644
> --- a/tools/perf/util/disasm.c
> +++ b/tools/perf/util/disasm.c
> @@ -16,6 +16,7 @@
> #include "debug.h"
> #include "disasm.h"
> #include "dso.h"
> +#include "vdso.h"
> #include "env.h"
> #include "evsel.h"
> #include "map.h"
> @@ -1126,7 +1127,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
> if (pos && strlen(pos) < SBUILD_ID_SIZE - 2)
> dirname(build_id_path);
>
> - if (dso__is_kcore(dso))
> + if (dso__is_kcore(dso) || dso__is_vdso(dso))
> goto fallback;
>
> len = readlink(build_id_path, linkname, sizeof(linkname) - 1);
> @@ -1134,7 +1135,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
> goto fallback;
>
> linkname[len] = '\0';
> - if (strstr(linkname, DSO__NAME_KALLSYMS) ||
> + if (strstr(linkname, DSO__NAME_KALLSYMS) || strstr(linkname, DSO__NAME_VDSO) ||
> access(filename, R_OK)) {
> fallback:
> /*
> @@ -1142,7 +1143,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
> * cache, or is just a kallsyms file, well, lets hope that this
> * DSO is the same as when 'perf record' ran.
> */
> - if (dso__kernel(dso) && dso__long_name(dso)[0] == '/')
> + if ((dso__kernel(dso) || dso__is_vdso(dso)) && dso__long_name(dso)[0] == '/')
> snprintf(filename, filename_size, "%s", dso__long_name(dso));
> else
> __symbol__join_symfs(filename, filename_size, dso__long_name(dso));
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 9e5940b5bc59..a90c647d37e1 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -19,6 +19,7 @@
> #include "build-id.h"
> #include "cap.h"
> #include "dso.h"
> +#include "vdso.h"
> #include "util.h" // lsdir()
> #include "debug.h"
> #include "event.h"
> @@ -44,6 +45,7 @@
>
> static int dso__load_kernel_sym(struct dso *dso, struct map *map);
> static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map);
> +static int dso__load_vdso_sym(struct dso *dso, struct map *map);
> static bool symbol__is_idle(const char *name);
>
> int vmlinux_path__nr_entries;
> @@ -1833,6 +1835,12 @@ int dso__load(struct dso *dso, struct map *map)
> goto out;
> }
>
> + if (dso__is_vdso(dso)) {
> + ret = dso__load_vdso_sym(dso, map);
> + if (ret > 0)
> + goto out;
> + }
> +
> dso__set_adjust_symbols(dso, false);
>
> if (perfmap) {
> @@ -2017,12 +2025,14 @@ int dso__load_vmlinux(struct dso *dso, struct map *map,
> dso__set_binary_type(dso, DSO_BINARY_TYPE__VMLINUX);
>
> err = dso__load_sym(dso, map, &ss, &ss, 0);
> - symsrc__destroy(&ss);
> -
> if (err > 0) {
> dso__set_loaded(dso);
> pr_debug("Using %s for symbols\n", symfs_vmlinux);
> +
> + if (symsrc__has_symtab(&ss) && !dso__symsrc_filename(dso))
> + dso__set_symsrc_filename(dso, strdup(symfs_vmlinux));
> }
> + symsrc__destroy(&ss);
>
> return err;
> }
> @@ -2349,6 +2359,74 @@ static int vmlinux_path__init(struct perf_env *env)
> return -1;
> }
>
> +int parse_vdso_pathnames(const struct option *opt __maybe_unused,
> + const char *arg, int unset __maybe_unused)
> +{
> + char *tmp, *tok, *str = strdup(arg);
> + unsigned int i = 0;
> +
> + for (tok = strtok_r(str, ",", &tmp); tok && i < ARRAY_SIZE(symbol_conf.vdso_name);
> + tok = strtok_r(NULL, ",", &tmp)) {
> + symbol_conf.vdso_name[i++] = strdup(tok);
> + }
> +
> + free(str);
> + return 0;
> +}
> +
> +static int dso__load_vdso(struct dso *dso, struct map *map,
> + const char *vdso)
> +{
> + int err = -1;
> + struct symsrc ss;
> + char symfs_vdso[PATH_MAX];
> +
> + if (vdso[0] == '/')
> + snprintf(symfs_vdso, sizeof(symfs_vdso), "%s", vdso);
> + else
> + symbol__join_symfs(symfs_vdso, vdso);
> +
> + if (symsrc__init(&ss, dso, symfs_vdso, DSO_BINARY_TYPE__SYSTEM_PATH_DSO))
> + return -1;
> +
> + /*
> + * dso__load_sym() may copy 'dso' which will result in the copies having
> + * an incorrect long name unless we set it here first.
> + */
> + dso__set_long_name(dso, vdso, false);
> + dso__set_binary_type(dso, DSO_BINARY_TYPE__SYSTEM_PATH_DSO);
> +
> + err = dso__load_sym(dso, map, &ss, &ss, 0);
> + if (err > 0) {
> + dso__set_loaded(dso);
> + pr_debug("Using %s for %s symbols\n", symfs_vdso, dso__short_name(dso));
> +
> + if (symsrc__has_symtab(&ss) && !dso__symsrc_filename(dso))
> + dso__set_symsrc_filename(dso, strdup(symfs_vdso));
> + }
> + symsrc__destroy(&ss);
> +
> + return err;
> +}
> +
> +static int dso__load_vdso_sym(struct dso *dso, struct map *map)
> +{
> + int ret;
> +
> + if (!dso__is_vdso(dso))
> + return -1;
> +
> + for (unsigned int i = 0; i < ARRAY_SIZE(symbol_conf.vdso_name); i++) {
> + if (symbol_conf.vdso_name[i] != NULL) {
> + ret = dso__load_vdso(dso, map, symbol_conf.vdso_name[i]);
> + if (ret > 0)
> + return ret;
> + }
> + }
> +
> + return -1;
> +}
> +
> int setup_list(struct strlist **list, const char *list_str,
> const char *list_name)
> {
> diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h
> index c114bbceef40..108356e3c981 100644
> --- a/tools/perf/util/symbol_conf.h
> +++ b/tools/perf/util/symbol_conf.h
> @@ -3,6 +3,7 @@
> #define __PERF_SYMBOL_CONF 1
>
> #include <stdbool.h>
> +#include <subcmd/parse-options.h>
>
> struct strlist;
> struct intlist;
> @@ -55,6 +56,7 @@ struct symbol_conf {
> const char *default_guest_vmlinux_name,
> *default_guest_kallsyms,
> *default_guest_modules;
> + const char *vdso_name[2];
> const char *guestmount;
> const char *dso_list_str,
> *comm_list_str,
> @@ -85,4 +87,7 @@ struct symbol_conf {
>
> extern struct symbol_conf symbol_conf;
>
> +int parse_vdso_pathnames(const struct option *opt __maybe_unused,
> + const char *arg, int unset __maybe_unused);
> +
> #endif // __PERF_SYMBOL_CONF
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