Merge patch series "Add 'trace wipe'"
Jerome Forissier <jerome.forissier@linaro.org> says:
This short series adds the 'trace wipe' command which clears the trace
buffer, allowing to re-start a capture from scratch.
Link: https://lore.kernel.org/r/cover.1734093566.git.jerome.forissier@linaro.org
diff --git a/cmd/trace.c b/cmd/trace.c
index 937e6a6..d360087 100644
--- a/cmd/trace.c
+++ b/cmd/trace.c
@@ -100,6 +100,10 @@
case 's':
trace_print_stats();
break;
+ case 'w':
+ if (trace_wipe())
+ return CMD_RET_FAILURE;
+ break;
default:
return CMD_RET_USAGE;
}
@@ -113,6 +117,7 @@
"stats - display tracing statistics\n"
"trace pause - pause tracing\n"
"trace resume - resume tracing\n"
+ "trace wipe - wipe traces\n"
"trace funclist [<addr> <size>] - dump function list into buffer\n"
"trace calls [<addr> <size>] "
"- dump function call trace into buffer"
diff --git a/doc/develop/trace.rst b/doc/develop/trace.rst
index 5468620..d3c8628 100644
--- a/doc/develop/trace.rst
+++ b/doc/develop/trace.rst
@@ -163,6 +163,17 @@
u-boot-1 [000] 3.116466: funcgraph_entry: 0.063 us | memset();
u-boot-1 [000] 3.116539: funcgraph_exit: 0.143 us | }
+The `trace wipe` command may be used to clear the trace buffer. It leaves
+tracing in its current enable state. This command is convenient when tracing a
+single command, for example:
+
+.. code-block:: console
+
+ => trace pause; trace wipe
+ => trace resume; dhcp; trace pause
+ => trace stats
+ ...
+
Flame graph
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diff --git a/include/trace.h b/include/trace.h
index 763d6d1..2bbaed9 100644
--- a/include/trace.h
+++ b/include/trace.h
@@ -100,6 +100,8 @@
int trace_early_init(void);
+int trace_wipe(void);
+
/**
* Init the trace system
*
diff --git a/lib/trace.c b/lib/trace.c
index cabbe47..1d5f7de 100644
--- a/lib/trace.c
+++ b/lib/trace.c
@@ -351,14 +351,8 @@
return gd->mon_len / FUNC_SITE_SIZE;
}
-/**
- * trace_init() - initialize the tracing system and enable it
- *
- * @buff: Pointer to trace buffer
- * @buff_size: Size of trace buffer
- * Return: 0 if ok
- */
-int notrace trace_init(void *buff, size_t buff_size)
+static int notrace trace_init_(void *buff, size_t buff_size, bool copy_early,
+ bool enable)
{
int func_count = get_func_count();
size_t needed;
@@ -368,7 +362,7 @@
return func_count;
trace_save_gd();
- if (!was_disabled) {
+ if (copy_early) {
#ifdef CONFIG_TRACE_EARLY
ulong used, count;
char *end;
@@ -394,9 +388,6 @@
}
puts("\n");
memcpy(buff, hdr, used);
-#else
- puts("trace: already enabled\n");
- return -EALREADY;
#endif
}
hdr = (struct trace_hdr *)buff;
@@ -419,13 +410,41 @@
hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
hdr->depth_limit = CONFIG_TRACE_CALL_DEPTH_LIMIT;
- puts("trace: enabled\n");
- trace_enabled = 1;
+ printf("trace: initialized, %senabled\n", enable ? "" : "not ");
+ trace_enabled = enable;
trace_inited = 1;
return 0;
}
+/**
+ * trace_init() - initialize the tracing system and enable it
+ *
+ * @buff: Pointer to trace buffer
+ * @buff_size: Size of trace buffer
+ * Return: 0 if ok
+ */
+int notrace trace_init(void *buff, size_t buff_size)
+{
+ /* If traces are enabled already, we may have early traces to copy */
+ return trace_init_(buff, buff_size, trace_enabled, true);
+}
+
+/**
+ * trace_wipe() - clear accumulated traced data
+ *
+ * May be called with tracing enabled or disabled.
+ */
+int notrace trace_wipe(void)
+{
+ bool was_enabled = trace_enabled;
+
+ if (trace_enabled)
+ trace_enabled = 0;
+ return trace_init_(gd->trace_buff, CONFIG_TRACE_BUFFER_SIZE,
+ false, was_enabled);
+}
+
#ifdef CONFIG_TRACE_EARLY
/**
* trace_early_init() - initialize the tracing system for early tracing
diff --git a/test/py/tests/test_trace.py b/test/py/tests/test_trace.py
index ec1e624..44239da 100644
--- a/test/py/tests/test_trace.py
+++ b/test/py/tests/test_trace.py
@@ -70,6 +70,32 @@
return fname, int(dm_f_time[0])
+def wipe_and_collect_trace(cons):
+ """Pause and wipe traces, return the number of calls (should be zero)
+
+ Args:
+ cons (ConsoleBase): U-Boot console
+
+ Returns:
+ int: the number of traced function calls reported by 'trace stats'
+ """
+ cons.run_command('trace pause')
+ cons.run_command('trace wipe')
+ out = cons.run_command('trace stats')
+
+ # The output is something like this:
+ # 117,221 function sites
+ # 0 function calls
+ # 0 untracked function calls
+ # 0 traced function calls
+
+ # Get a dict of values from the output
+ lines = [line.split(maxsplit=1) for line in out.splitlines() if line]
+ vals = {key: val.replace(',', '') for val, key in lines}
+
+ return int(vals['traced function calls'])
+
+
def check_function(cons, fname, proftool, map_fname, trace_dat):
"""Check that the 'function' output works
@@ -304,3 +330,7 @@
# This allows for CI being slow to run
diff = abs(fg_time - dm_f_time)
assert diff / dm_f_time < 0.3
+
+ # Check that the trace buffer can be wiped
+ numcalls = wipe_and_collect_trace(cons)
+ assert numcalls == 0