On Fri, 08 Aug 2025 05:06, Pierrick Bouvier <pierrick.bouv...@linaro.org> wrote:
>Beyond traces per cpu, uftrace expect to find some specific files.
>- info: contains information about machine/program run
> those values are not impacting uftrace behaviour, and we simply copied
> a random example to keep things simple.
>- memory mapping: how every binary is mapped in memory. For system mode,
> we generate an empty mapping (uftrace_symbols.py, coming in future
> commit, will take care of that). For user mode, we copy current
> /proc/self/maps. We don't need to do any special filtering, as
> reported addresses will necessarily concern guest program, and not
> QEMU and its libraries.
>- task: list of tasks. We present every vcpu/privilege level as a
> separate process, as it's the best view we can have when generating a
> (visual) chrome trace. Using threads is less convenient in terms of
> UI.
>
>Signed-off-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
>---
> contrib/plugins/uftrace.c | 130 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 129 insertions(+), 1 deletion(-)
>
>diff --git a/contrib/plugins/uftrace.c b/contrib/plugins/uftrace.c
>index 7737626da2f..6628b4256fd 100644
>--- a/contrib/plugins/uftrace.c
>+++ b/contrib/plugins/uftrace.c
>@@ -115,6 +115,126 @@ static uint64_t gettime_ns(void)
> return now_ns;
> }
>
>+static void uftrace_write_map(bool system_emulation)
>+{
>+ const char *path = "./uftrace.data/sid-0.map";
>+
>+ if (system_emulation && access(path, F_OK) == 0) {
>+ /* do not erase existing map in system emulation, as a custom one
>might
>+ * already have been generated by uftrace_symbols.py */
>+ return;
>+ }
>+
>+ FILE *sid_map = fopen(path, "w");
>+ g_assert(sid_map);
>+
>+ if (system_emulation) {
>+ fprintf(sid_map,
>+ "# map stack on highest address possible, to prevent
>uftrace\n"
>+ "# from considering any kernel address\n");
>+ fprintf(sid_map,
>+ "ffffffffffff-ffffffffffff rw-p 00000000 00:00 0 [stack]\n");
>+ } else {
>+ /* in user mode, copy /proc/self/maps instead */
>+ FILE *self_map = fopen("/proc/self/maps", "r");
>+ g_assert(self_map);
>+ for (;;) {
>+ int c = fgetc(self_map);
>+ if (c == EOF) {
>+ break;
>+ }
>+ fputc(c, sid_map);
>+ }
>+ fclose(self_map);
>+ }
>+ fclose(sid_map);
>+}
>+
>+static void uftrace_write_task(const GArray *traces)
>+{
>+ FILE *task = fopen("./uftrace.data/task.txt", "w");
>+ g_assert(task);
>+ for (int i = 0; i < traces->len; ++i) {
>+ Trace *t = g_array_index(traces, Trace*, i);
>+ fprintf(task, "SESS timestamp=0.0 pid=%"PRIu32" sid=0
>exename=\"%s\"\n",
>+ t->id, t->name->str);
>+ fprintf(task, "TASK timestamp=0.0 tid=%"PRIu32" pid=%"PRIu32"\n",
>+ t->id, t->id);
>+ }
>+ fclose(task);
>+}
>+
>+static void uftrace_write_info(const GArray *traces)
>+{
>+ g_autoptr(GString) taskinfo_tids = g_string_new("taskinfo:tids=");
>+ for (int i = 0; i < traces->len; ++i) {
>+ Trace *t = g_array_index(traces, Trace*, i);
>+ const char *delim = i > 0 ? "," : "";
>+ g_string_append_printf(taskinfo_tids, "%s%"PRIu32, delim, t->id);
>+ }
>+
>+ g_autoptr(GString) taskinfo_nr_tid = g_string_new("taskinfo:nr_tid=");
>+ g_string_append_printf(taskinfo_nr_tid, "%d", traces->len);
>+
>+ FILE *info = fopen("./uftrace.data/info", "w");
>+ g_assert(info);
>+ /*
>+ * $ uftrace dump --debug
>+ * uftrace file header: magic = 4674726163652100
>+ * uftrace file header: version = 4
>+ * uftrace file header: header size = 40
>+ * uftrace file header: endian = 1 (little)
>+ * uftrace file header: class = 2 (64 bit)
>+ * uftrace file header: features = 0x1263 (PLTHOOK | ...
>+ * uftrace file header: info = 0x7bff (EXE_NAME | ...
>+ * <0000000000000000>: 46 74 72 61 63 65 21 00 04 00 00 00 28 00 01 02
>+ * <0000000000000010>: 63 12 00 00 00 00 00 00 ff 7b 00 00 00 00 00 00
>+ * <0000000000000020>: 00 04 00 00 00 00 00 00
>+ */
>+ const uint8_t header[] = {0x46, 0x74, 0x72, 0x61, 0x63, 0x65, 0x21, 0x00,
>+ 0x04, 0x00, 0x00, 0x00, 0x28, 0x00, 0x01, 0x02,
>+ 0x63, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>+ 0xff, 0x7b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>+ 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
>+ fwrite(header, sizeof(header), 1, info);
>+ const char *info_data[] = {
>+ "exename:from_qemu",
>+ "build_id:0123456789abcdef0123456789abcdef01234567",
>+ "exit_status:0",
>+ "cmdline:uftrace record qemu",
>+ "cpuinfo:lines=2",
>+ "cpuinfo:nr_cpus=1 / 1 (online/possible)",
>+ "cpuinfo:desc=Intel 8086",
Haha what :D
>+ "meminfo:1.0 / 1.0 GB (free / total)",
>+ "osinfo:lines=3",
>+ "osinfo:kernel=Linux 6.12.33",
>+ "osinfo:hostname=pc",
>+ "osinfo:distro=\"Debian GNU/Linux 13 (trixie)\"",
So I assume these strings can be anything, why not make them blank?
>+ "taskinfo:lines=2",
>+ taskinfo_nr_tid->str,
>+ taskinfo_tids->str,
>+ "usageinfo:lines=6",
>+ "usageinfo:systime=0.000000",
>+ "usageinfo:usrtime=0.000000",
>+ "usageinfo:ctxsw=0 / 0 (voluntary / involuntary)",
>+ "usageinfo:maxrss=8016",
>+ "usageinfo:pagefault=0 / 0 (major / minor)",
>+ "usageinfo:iops=0 / 0 (read / write)",
>+ "loadinfo:0.0 / 0.0 / 0.0",
>+ "record_date:Mon Jan 1 00:00:00 2025",
>+ "elapsed_time:1000000000000.0 sec",
>+ "pattern_type:regex",
>+ "uftrace_version:v0.17 ( x86_64 dwarf python3 luajit tui perf sched
>dynamic kernel )",
>+ "utc_offset:1751552954",
>+ 0};
>+ const char **info_data_it = info_data;
>+ while (*(info_data_it)) {
>+ fprintf(info, "%s\n", *info_data_it);
>+ ++info_data_it;
>+ }
>+ fclose(info);
>+}
>+
> static Callstack *callstack_new(void)
> {
> Callstack *cs = g_new0(Callstack, 1);
>@@ -607,14 +727,22 @@ static void vcpu_end(unsigned int vcpu_index)
>
> static void at_exit(qemu_plugin_id_t id, void *data)
> {
>+ bool system_emulation = (bool) data;
>+ g_autoptr(GArray) traces = g_array_new(0, 0, sizeof(Trace *));
>+
> for (size_t i = 0; i < qemu_plugin_num_vcpus(); ++i) {
> Cpu *cpu = qemu_plugin_scoreboard_find(score, i);
> for (size_t j = 0; j < cpu->traces->len; ++j) {
> Trace *t = g_array_index(cpu->traces, Trace*, j);
> trace_flush(t, true);
>+ g_array_append_val(traces, t);
> }
> }
>
>+ uftrace_write_map(system_emulation);
>+ uftrace_write_info(traces);
>+ uftrace_write_task(traces);
>+
> for (size_t i = 0; i < qemu_plugin_num_vcpus(); ++i) {
> vcpu_end(i);
> }
>@@ -651,7 +779,7 @@ QEMU_PLUGIN_EXPORT int
>qemu_plugin_install(qemu_plugin_id_t id,
>
> score = qemu_plugin_scoreboard_new(sizeof(Cpu));
> qemu_plugin_register_vcpu_init_cb(id, vcpu_init);
>- qemu_plugin_register_atexit_cb(id, at_exit, NULL);
>+ qemu_plugin_register_atexit_cb(id, at_exit, (void *)
>info->system_emulation);
> qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
>
> return 0;
>--
>2.47.2
>
LGTM,
Reviewed-by: Manos Pitsidianakis <manos.pitsidiana...@linaro.org>
