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",
+ "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)\"",
+ "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
