[PATCH v4] perf: Add layout support for --symfs option

Changbin Du
2026-03-09T09:29:43Z

Add support for parsing an optional layout parameter in the --symfs
command line option. The format is:

--symfs <directory[,layout]>

Where layout can be:
- 'hierarchy': matches full path (default)
- 'flat': only matches base name

When debugging symbol files from a copy of the filesystem (e.g., from a
container or remote machine), the debug files are often stored in a
flat directory structure with only filenames, not the full original
paths. In this case, using 'flat' layout allows perf to find debug
symbols by matching only the filename rather than the full path.

For example, given a binary path like:
/build/output/lib/foo.so

With 'perf report --symfs /debug/files,flat', perf will look for:
/debug/files/foo.so

Instead of:
/debug/files/build/output/lib/foo.so

This is particularly useful when:
- Extracting debug files from containers with different directory layouts
- Working with build systems that flatten directory structures

Changes:
- Add symfs_layout_flat field to symbol_conf struct.
- Parse optional layout in symbol__config_symfs().
- Modify __symbol__join_symfs() to use basename() when layout
is 'flat'.
- Update documentation in Documentation/ folder.

Signed-off-by: Changbin Du <changbin.du@huawei.com>

---
v4:
Ouput error if an invalid layout (not "flat" or "hierarchy") is provided.
v3:
Handle paths containing commas in symbol__config_symfs().
v2:
Renaming the new option from 'match_mode' to 'layout', as it better
aligns with the conventions of technical terminology.
---
tools/perf/Documentation/perf-annotate.txt | 7 +++--
tools/perf/Documentation/perf-diff.txt | 7 +++--
tools/perf/Documentation/perf-kwork.txt | 7 +++--
tools/perf/Documentation/perf-probe.txt | 6 ++++
tools/perf/Documentation/perf-report.txt | 7 +++--
tools/perf/Documentation/perf-sched.txt | 7 +++--
tools/perf/Documentation/perf-script.txt | 7 +++--
tools/perf/Documentation/perf-timechart.txt | 7 +++--
tools/perf/Documentation/tips.txt | 2 +-
tools/perf/builtin-annotate.c | 3 +-
tools/perf/builtin-diff.c | 3 +-
tools/perf/builtin-kwork.c | 4 +--
tools/perf/builtin-probe.c | 4 +--
tools/perf/builtin-report.c | 3 +-
tools/perf/builtin-sched.c | 4 +--
tools/perf/builtin-script.c | 3 +-
tools/perf/builtin-timechart.c | 3 +-
tools/perf/util/symbol.c | 35 ++++++++++++++++++---
tools/perf/util/symbol.h | 18 +++++++++++
tools/perf/util/symbol_conf.h | 1 +
20 files changed, 103 insertions(+), 35 deletions(-)

diff --git a/tools/perf/Documentation/perf-annotate.txt b/tools/perf/Documentation/perf-annotate.txt
index 547f1a268018..a688738809c4 100644
--- a/tools/perf/Documentation/perf-annotate.txt
+++ b/tools/perf/Documentation/perf-annotate.txt
@@ -110,8 +110,11 @@ include::itrace.txt[]
Interleave source code with assembly code. Enabled by default,
disable with --no-source.

---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.

-M::
--disassembler-style=:: Set disassembler style for objdump.
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 58efab72d2e5..8e4a3f093135 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -81,8 +81,11 @@ OPTIONS
--force::
Don't do ownership validation.

---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.

-b::
--baseline-only::
diff --git a/tools/perf/Documentation/perf-kwork.txt b/tools/perf/Documentation/perf-kwork.txt
index 21e607669d78..5c33a1fb2ffe 100644
--- a/tools/perf/Documentation/perf-kwork.txt
+++ b/tools/perf/Documentation/perf-kwork.txt
@@ -169,8 +169,11 @@ OPTIONS for 'perf kwork timehist'
--max-stack::
Maximum number of functions to display in backtrace, default 5.

---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.

--time::
Only analyze samples within given time window: <start>,<stop>. Times
diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 5c43a6edc0e5..2e5790325430 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -50,6 +50,12 @@ OPTIONS
--source=PATH::
Specify path to kernel source.

+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.
+
-v::
--verbose::
Be more verbose (show parsed arguments, etc).
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index acef3ff4178e..802f931ae64d 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -368,8 +368,11 @@ OPTIONS
--force::
Don't do ownership validation.

---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.

-C::
--cpu:: Only report samples for the list of CPUs provided. Multiple CPUs can
diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
index 4d9981609c04..a4221398e5e0 100644
--- a/tools/perf/Documentation/perf-sched.txt
+++ b/tools/perf/Documentation/perf-sched.txt
@@ -437,8 +437,11 @@ OPTIONS for 'perf sched timehist'
Show all scheduling events followed by a summary by thread with min,
max, and average run times (in sec) and relative stddev.

---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.

-V::
--cpu-visual::
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index ddf92f9c7821..200ea25891d8 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -307,8 +307,11 @@ OPTIONS
--kallsyms=<file>::
kallsyms pathname

---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.

-G::
--hide-call-graph::
diff --git a/tools/perf/Documentation/perf-timechart.txt b/tools/perf/Documentation/perf-timechart.txt
index ef2281c56743..bacc5df3c400 100644
--- a/tools/perf/Documentation/perf-timechart.txt
+++ b/tools/perf/Documentation/perf-timechart.txt
@@ -53,8 +53,11 @@ TIMECHART OPTIONS
-f::
--force::
Don't complain, do it.
---symfs=<directory>::
- Look for files with symbols relative to this directory.
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.
-n::
--proc-num::
Print task info for at least given number of tasks.
diff --git a/tools/perf/Documentation/tips.txt b/tools/perf/Documentation/tips.txt
index 3fee9b2a88ea..ebf12a8c5db5 100644
--- a/tools/perf/Documentation/tips.txt
+++ b/tools/perf/Documentation/tips.txt
@@ -11,7 +11,7 @@ Search options using a keyword: perf report -h <keyword>
Use parent filter to see specific call path: perf report -p <regex>
List events using substring match: perf list <keyword>
To see list of saved events and attributes: perf evlist -v
-Use --symfs if your symbol files are in non-standard locations
+Use --symfs [,layout] if your symbol files are in non-standard locations.
To see callchains in a more compact form: perf report -g folded
To see call chains by final symbol taking CPU time (bottom up) use perf report -G
Show individual samples with: perf script
diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 9c27bb30b708..686ad08561d6 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -744,8 +744,7 @@ int cmd_annotate(int argc, const char **argv)
&annotate.group_set,
"Show event group information together"),
OPT_STRING('C', "cpu", &annotate.cpu_list, "cpu", "list of cpus to profile"),
- OPT_CALLBACK(0, "symfs", NULL, "directory",
- "Look for files with symbols relative to this directory",
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
symbol__config_symfs),
OPT_BOOLEAN(0, "source", &annotate_opts.annotate_src,
"Interleave source code with assembly code (default)"),
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 59bf1f72d12e..69069926dd0b 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -1280,8 +1280,7 @@ static const struct option options[] = {
OPT_STRING_NOEMPTY('t', "field-separator", &symbol_conf.field_sep, "separator",
"separator for columns, no spaces will be added between "
"columns '.' is reserved."),
- OPT_CALLBACK(0, "symfs", NULL, "directory",
- "Look for files with symbols relative to this directory",
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
symbol__config_symfs),
OPT_UINTEGER('o', "order", &sort_compute, "Specify compute sorting."),
OPT_CALLBACK(0, "percentage", NULL, "relative|absolute",
diff --git a/tools/perf/builtin-kwork.c b/tools/perf/builtin-kwork.c
index 7f3068264568..6f94a8f45f60 100644
--- a/tools/perf/builtin-kwork.c
+++ b/tools/perf/builtin-kwork.c
@@ -2423,8 +2423,8 @@ int cmd_kwork(int argc, const char **argv)
"Display call chains if present"),
OPT_UINTEGER(0, "max-stack", &kwork.max_stack,
"Maximum number of functions to display backtrace."),
- OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
- "Look for files with symbols relative to this directory"),
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
+ symbol__config_symfs),
OPT_STRING(0, "time", &kwork.time_str, "str",
"Time span for analysis (start,stop)"),
OPT_STRING('C', "cpu", &kwork.cpu_list, "cpu",
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 1b4ba85ee019..a67b565278ae 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -597,8 +597,8 @@ __cmd_probe(int argc, const char **argv)
OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel,
"Enable kernel symbol demangling"),
OPT_BOOLEAN(0, "cache", &probe_conf.cache, "Manipulate probe cache"),
- OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
- "Look for files with symbols relative to this directory"),
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
+ symbol__config_symfs),
OPT_CALLBACK(0, "target-ns", NULL, "pid",
"target pid for namespace contexts", opt_set_target_ns),
OPT_BOOLEAN(0, "bootconfig", &probe_conf.bootconfig,
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 3b81f4b3dc49..343c0ada5ea1 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1416,8 +1416,7 @@ int cmd_report(int argc, const char **argv)
"columns '.' is reserved."),
OPT_BOOLEAN('U', "hide-unresolved", &symbol_conf.hide_unresolved,
"Only display entries resolved to a symbol"),
- OPT_CALLBACK(0, "symfs", NULL, "directory",
- "Look for files with symbols relative to this directory",
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
symbol__config_symfs),
OPT_STRING('C', "cpu", &report.cpu_list, "cpu",
"list of cpus to profile"),
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 3f509cfdd58c..d083e2bb7703 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -4879,8 +4879,8 @@ int cmd_sched(int argc, const char **argv)
"Display call chains if present (default on)"),
OPT_UINTEGER(0, "max-stack", &sched.max_stack,
"Maximum number of functions to display backtrace."),
- OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
- "Look for files with symbols relative to this directory"),
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
+ symbol__config_symfs),
OPT_BOOLEAN('s', "summary", &sched.summary_only,
"Show only syscall summary with statistics"),
OPT_BOOLEAN('S', "with-summary", &sched.summary,
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 7c743a303507..9912199d22da 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -4074,8 +4074,7 @@ int cmd_script(int argc, const char **argv)
"file", "kallsyms pathname"),
OPT_BOOLEAN('G', "hide-call-graph", &no_callchain,
"When printing symbols do not display call chain"),
- OPT_CALLBACK(0, "symfs", NULL, "directory",
- "Look for files with symbols relative to this directory",
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
symbol__config_symfs),
OPT_CALLBACK('F', "fields", NULL, "str",
"comma separated output fields prepend with 'type:'. "
diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index f8b49d69e9a5..28f33e39895d 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -1951,8 +1951,7 @@ int cmd_timechart(int argc, const char **argv)
OPT_CALLBACK('p', "process", NULL, "process",
"process selector. Pass a pid or process name.",
parse_process),
- OPT_CALLBACK(0, "symfs", NULL, "directory",
- "Look for files with symbols relative to this directory",
+ OPT_CALLBACK(0, "symfs", NULL, "directory[,layout]", SYMFS_HELP,
symbol__config_symfs),
OPT_INTEGER('n', "proc-num", &tchart.proc_num,
"min. number of tasks to print"),
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 8662001e1e25..bd811b2b7890 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -66,6 +66,7 @@ struct symbol_conf symbol_conf = {
.time_quantum = 100 * NSEC_PER_MSEC, /* 100ms */
.show_hist_headers = true,
.symfs = "",
+ .symfs_layout_flat = false,
.event_group = true,
.inline_name = true,
.res_sample = 0,
@@ -2491,16 +2492,42 @@ int symbol__config_symfs(const struct option *opt __maybe_unused,
const char *dir, int unset __maybe_unused)
{
char *bf = NULL;
+ char *layout_str;
+ char *dir_copy;
int ret;

- symbol_conf.symfs = strdup(dir);
- if (symbol_conf.symfs == NULL)
- return -ENOMEM;
+ layout_str = strrchr(dir, ',');
+ if (layout_str) {
+ size_t dir_len = layout_str - dir;
+
+ dir_copy = strndup(dir, dir_len);
+ if (dir_copy == NULL)
+ return -ENOMEM;
+
+ symbol_conf.symfs = dir_copy;
+
+ layout_str++;
+ if (!strcmp(layout_str, "flat"))
+ symbol_conf.symfs_layout_flat = true;
+ else if (!strcmp(layout_str, "hierarchy"))
+ symbol_conf.symfs_layout_flat = false;
+ else {
+ pr_err("Invalid layout: '%s', use 'hierarchy' or 'flat'\n",
+ layout_str);
+ free(dir_copy);
+ return -EINVAL;
+ }
+ } else {
+ symbol_conf.symfs = strdup(dir);
+ if (symbol_conf.symfs == NULL)
+ return -ENOMEM;
+ symbol_conf.symfs_layout_flat = false;
+ }

/* skip the locally configured cache if a symfs is given, and
* config buildid dir to symfs/.debug
*/
- ret = asprintf(&bf, "%s/%s", dir, ".debug");
+ ret = asprintf(&bf, "%s/%s", symbol_conf.symfs, ".debug");
if (ret < 0)
return -ENOMEM;

diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 3fb5d146d9b1..4f1dbd1ebd99 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -9,6 +9,7 @@
#include <linux/list.h>
#include <linux/rbtree.h>
#include <stdio.h>
+#include <errno.h>
#include "addr_location.h"
#include "path.h"
#include "symbol_conf.h"
@@ -96,6 +97,18 @@ struct intlist;

static inline int __symbol__join_symfs(char *bf, size_t size, const char *path)
{
+ if (symbol_conf.symfs_layout_flat) {
+ char *path_copy = strdup(path);
+ char *base;
+ int ret;
+
+ if (!path_copy)
+ return -ENOMEM;
+ base = basename(path_copy);
+ ret = path__join(bf, size, symbol_conf.symfs, base);
+ free(path_copy);
+ return ret;
+ }
return path__join(bf, size, symbol_conf.symfs, path);
}

@@ -169,6 +182,11 @@ size_t symbol__fprintf_symname(const struct symbol *sym, FILE *fp);
size_t symbol__fprintf(struct symbol *sym, FILE *fp);
bool symbol__restricted_filename(const char *filename,
const char *restricted_filename);
+
+#define SYMFS_HELP "setup root directory which contains debug files:\n" \
+ "\t\t\t\t" "directory:\tLook for files with symbols relative to this directory.\n" \
+ "\t\t\t\t" "layout: \tLayout of files, 'hierarchy' matches full path (default), 'flat' only matches base name.\n"
+
int symbol__config_symfs(const struct option *opt __maybe_unused,
const char *dir, int unset __maybe_unused);

diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h
index 71bb17372a6c..ac1b444a8fd8 100644
--- a/tools/perf/util/symbol_conf.h
+++ b/tools/perf/util/symbol_conf.h
@@ -93,6 +93,7 @@ struct symbol_conf {
*tid_list,
*addr_list;
const char *symfs;
+ bool symfs_layout_flat;
int res_sample;
int pad_output_len_dso;
int group_sort_idx;
--
2.43.0