https://github.com/python/cpython/commit/375c94c75dd9eaefaddd89a7f704a031441af286
commit: 375c94c75dd9eaefaddd89a7f704a031441af286
branch: main
author: Tian Gao <[email protected]>
committer: markshannon <[email protected]>
date: 2024-04-29T09:54:52+01:00
summary:
gh-107674: Lazy load line number to improve performance of tracing (GH-118127)
files:
A Misc/NEWS.d/next/Core and
Builtins/2024-04-20-20-30-15.gh-issue-107674.GZPOP7.rst
M Objects/frameobject.c
M Python/instrumentation.c
M Python/legacy_tracing.c
diff --git a/Misc/NEWS.d/next/Core and
Builtins/2024-04-20-20-30-15.gh-issue-107674.GZPOP7.rst b/Misc/NEWS.d/next/Core
and Builtins/2024-04-20-20-30-15.gh-issue-107674.GZPOP7.rst
new file mode 100644
index 00000000000000..29d16bd7dd6581
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and
Builtins/2024-04-20-20-30-15.gh-issue-107674.GZPOP7.rst
@@ -0,0 +1 @@
+Lazy load frame line number to improve performance of tracing
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 07b7ef3df46a5c..36538b1f6d53fe 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -41,12 +41,20 @@ int
PyFrame_GetLineNumber(PyFrameObject *f)
{
assert(f != NULL);
- if (f->f_lineno != 0) {
- return f->f_lineno;
+ if (f->f_lineno == -1) {
+ // We should calculate it once. If we can't get the line number,
+ // set f->f_lineno to 0.
+ f->f_lineno = PyUnstable_InterpreterFrame_GetLine(f->f_frame);
+ if (f->f_lineno < 0) {
+ f->f_lineno = 0;
+ return -1;
+ }
}
- else {
- return PyUnstable_InterpreterFrame_GetLine(f->f_frame);
+
+ if (f->f_lineno > 0) {
+ return f->f_lineno;
}
+ return PyUnstable_InterpreterFrame_GetLine(f->f_frame);
}
static PyObject *
diff --git a/Python/instrumentation.c b/Python/instrumentation.c
index 71efeff077633d..328a3b1733d604 100644
--- a/Python/instrumentation.c
+++ b/Python/instrumentation.c
@@ -268,14 +268,15 @@ get_events(_Py_GlobalMonitors *m, int tool_id)
* 8 bit value.
* if line_delta == -128:
* line = None # represented as -1
- * elif line_delta == -127:
+ * elif line_delta == -127 or line_delta == -126:
* line = PyCode_Addr2Line(code, offset * sizeof(_Py_CODEUNIT));
* else:
* line = first_line + (offset >> OFFSET_SHIFT) + line_delta;
*/
#define NO_LINE -128
-#define COMPUTED_LINE -127
+#define COMPUTED_LINE_LINENO_CHANGE -127
+#define COMPUTED_LINE -126
#define OFFSET_SHIFT 4
@@ -302,7 +303,7 @@ compute_line(PyCodeObject *code, int offset, int8_t
line_delta)
return -1;
}
- assert(line_delta == COMPUTED_LINE);
+ assert(line_delta == COMPUTED_LINE || line_delta ==
COMPUTED_LINE_LINENO_CHANGE);
/* Look it up */
return PyCode_Addr2Line(code, offset * sizeof(_Py_CODEUNIT));
}
@@ -1224,18 +1225,26 @@ _Py_call_instrumentation_line(PyThreadState *tstate,
_PyInterpreterFrame* frame,
}
PyInterpreterState *interp = tstate->interp;
int8_t line_delta = line_data->line_delta;
- int line = compute_line(code, i, line_delta);
- assert(line >= 0);
- assert(prev != NULL);
- int prev_index = (int)(prev - _PyCode_CODE(code));
- int prev_line = _Py_Instrumentation_GetLine(code, prev_index);
- if (prev_line == line) {
- int prev_opcode = _PyCode_CODE(code)[prev_index].op.code;
- /* RESUME and INSTRUMENTED_RESUME are needed for the operation of
- * instrumentation, so must never be hidden by an INSTRUMENTED_LINE.
- */
- if (prev_opcode != RESUME && prev_opcode != INSTRUMENTED_RESUME) {
- goto done;
+ int line = 0;
+
+ if (line_delta == COMPUTED_LINE_LINENO_CHANGE) {
+ // We know the line number must have changed, don't need to calculate
+ // the line number for now because we might not need it.
+ line = -1;
+ } else {
+ line = compute_line(code, i, line_delta);
+ assert(line >= 0);
+ assert(prev != NULL);
+ int prev_index = (int)(prev - _PyCode_CODE(code));
+ int prev_line = _Py_Instrumentation_GetLine(code, prev_index);
+ if (prev_line == line) {
+ int prev_opcode = _PyCode_CODE(code)[prev_index].op.code;
+ /* RESUME and INSTRUMENTED_RESUME are needed for the operation of
+ * instrumentation, so must never be hidden by an
INSTRUMENTED_LINE.
+ */
+ if (prev_opcode != RESUME && prev_opcode != INSTRUMENTED_RESUME) {
+ goto done;
+ }
}
}
@@ -1260,6 +1269,12 @@ _Py_call_instrumentation_line(PyThreadState *tstate,
_PyInterpreterFrame* frame,
tstate->tracing++;
/* Call c_tracefunc directly, having set the line number. */
Py_INCREF(frame_obj);
+ if (line == -1 && line_delta > COMPUTED_LINE) {
+ /* Only assign f_lineno if it's easy to calculate,
otherwise
+ * do lazy calculation by setting the f_lineno to 0.
+ */
+ line = compute_line(code, i, line_delta);
+ }
frame_obj->f_lineno = line;
int err = tstate->c_tracefunc(tstate->c_traceobj, frame_obj,
PyTrace_LINE, Py_None);
frame_obj->f_lineno = 0;
@@ -1276,6 +1291,11 @@ _Py_call_instrumentation_line(PyThreadState *tstate,
_PyInterpreterFrame* frame,
if (tools == 0) {
goto done;
}
+
+ if (line == -1) {
+ /* Need to calculate the line number now for monitoring events */
+ line = compute_line(code, i, line_delta);
+ }
PyObject *line_obj = PyLong_FromLong(line);
if (line_obj == NULL) {
return -1;
@@ -1477,6 +1497,13 @@ initialize_lines(PyCodeObject *code)
*/
if (line != current_line && line >= 0) {
line_data[i].original_opcode = opcode;
+ if (line_data[i].line_delta == COMPUTED_LINE) {
+ /* Label this line as a line with a line number change
+ * which could help the monitoring callback to quickly
+ * identify the line number change.
+ */
+ line_data[i].line_delta = COMPUTED_LINE_LINENO_CHANGE;
+ }
}
else {
line_data[i].original_opcode = 0;
@@ -1529,6 +1556,11 @@ initialize_lines(PyCodeObject *code)
assert(target >= 0);
if (line_data[target].line_delta != NO_LINE) {
line_data[target].original_opcode = _Py_GetBaseOpcode(code,
target);
+ if (line_data[target].line_delta == COMPUTED_LINE_LINENO_CHANGE) {
+ // If the line is a jump target, we are not sure if the line
+ // number changes, so we set it to COMPUTED_LINE.
+ line_data[target].line_delta = COMPUTED_LINE;
+ }
}
}
/* Scan exception table */
diff --git a/Python/legacy_tracing.c b/Python/legacy_tracing.c
index b5a17405931825..74118030925e3e 100644
--- a/Python/legacy_tracing.c
+++ b/Python/legacy_tracing.c
@@ -174,6 +174,7 @@ call_trace_func(_PyLegacyEventHandler *self, PyObject *arg)
Py_INCREF(frame);
int err = tstate->c_tracefunc(tstate->c_traceobj, frame, self->event, arg);
+ frame->f_lineno = 0;
Py_DECREF(frame);
if (err) {
return NULL;
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