diff options
| -rwxr-xr-x | tools/perf/tests/shell/test_dwarf_unwind_multithreaded.sh | 65 | ||||
| -rw-r--r-- | tools/perf/util/unwind-libdw.c | 24 |
2 files changed, 86 insertions, 3 deletions
diff --git a/tools/perf/tests/shell/test_dwarf_unwind_multithreaded.sh b/tools/perf/tests/shell/test_dwarf_unwind_multithreaded.sh new file mode 100755 index 000000000000..49e6e3af771f --- /dev/null +++ b/tools/perf/tests/shell/test_dwarf_unwind_multithreaded.sh @@ -0,0 +1,65 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# Test libdw unwinding of multi-threaded processes (exclusive) + +set -e + +if ! perf check feature -q libdw-dwarf-unwind; then + echo "Skip: libdw DWARF unwinding is not available" + exit 2 +fi + +tmpdir=$(mktemp -d /tmp/perf-test-dwarf-unwind-multithreaded.XXXXXX) +perf_data="$tmpdir/perf.data" +perf_script="$tmpdir/perf-script.txt" +nr_threads=4 +nr_worker_threads=$((nr_threads - 1)) + +cleanup() +{ + trap - EXIT TERM INT + rm -rf "$tmpdir" +} + +trap cleanup EXIT TERM INT + +if ! perf record -q -e task-clock:u -F 99 --call-graph dwarf,8192 \ + -o "$perf_data" -- perf test -w thloop 2 "$nr_threads" +then + echo "Skip: failed to record task-clock:u" + exit 2 +fi + +if ! perf script --unwind-style=libdw \ + -F comm,pid,tid,event,ip,sym -i "$perf_data" > "$perf_script" +then + echo "Error: failed to process the recording with libdw" >&2 + exit 1 +fi + +nr_unwound_threads=$( + awk ' + BEGIN { RS = "" } + + # thfunc is the worker-only caller of test_loop. Finding it proves + # that libdw unwound beyond the sampled leaf for this worker TID. + /thfunc/ { + split($2, id, "/") + seen[id[2]] = 1 + } + + END { + for (tid in seen) + nr_tids++ + print nr_tids + 0 + } + ' "$perf_script" +) + +if [ "$nr_unwound_threads" -ne "$nr_worker_threads" ]; then + echo "Error: expected callchains for $nr_worker_threads worker TIDs," \ + "found $nr_unwound_threads" >&2 + exit 1 +fi + +exit 0 diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c index 7f35042be567..63a5c2253174 100644 --- a/tools/perf/util/unwind-libdw.c +++ b/tools/perf/util/unwind-libdw.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 +#include <assert.h> #include <linux/compiler.h> #include <elfutils/libdw.h> #include <elfutils/libdwfl.h> @@ -173,14 +174,30 @@ static int entry(u64 ip, struct unwind_info *ui) return 0; } -static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp) +static pid_t next_thread(Dwfl *dwfl __maybe_unused, void *arg, void **thread_argp) { + struct dwfl_ui_thread_info *dwfl_ui_ti = arg; + /* We want only single thread to be processed. */ if (*thread_argp != NULL) return 0; + assert(dwfl_ui_ti->ui != NULL); *thread_argp = arg; - return dwfl_pid(dwfl); + return thread__tid(dwfl_ui_ti->ui->thread); +} + +static bool get_thread(Dwfl *dwfl __maybe_unused, pid_t tid, void *arg, + void **thread_argp) +{ + struct dwfl_ui_thread_info *dwfl_ui_ti = arg; + + assert(dwfl_ui_ti->ui != NULL); + if (tid != thread__tid(dwfl_ui_ti->ui->thread)) + return false; + + *thread_argp = arg; + return true; } static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr, @@ -306,6 +323,7 @@ static bool libdw_set_initial_registers(Dwfl_Thread *thread, void *arg) static const Dwfl_Thread_Callbacks callbacks = { .next_thread = next_thread, + .get_thread = get_thread, .memory_read = memory_read, .set_initial_registers = libdw_set_initial_registers, }; @@ -400,7 +418,7 @@ int libdw__get_entries(unwind_entry_cb_t cb, void *arg, if (err) goto out; - dwfl_attach_state(dwfl, /*elf=*/NULL, thread__tid(thread), &callbacks, + dwfl_attach_state(dwfl, /*elf=*/NULL, thread__pid(thread), &callbacks, /* Dwfl thread function argument*/dwfl_ui_ti); // Ignore thread already attached error. |