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gh-107674: Lazy load line number to improve performance of tracing (GH-118127)

This commit is contained in:
Tian Gao 2024-04-29 01:54:52 -07:00 committed by GitHub
parent c7e7bfc4ca
commit 375c94c75d
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GPG Key ID: B5690EEEBB952194
4 changed files with 61 additions and 19 deletions
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1
Misc/NEWS.d/next/Core and Builtins/2024-04-20-20-30-15.gh-issue-107674.GZPOP7.rst Normal file
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@ -0,0 +1 @@
Lazy load frame line number to improve performance of tracing

16
Objects/frameobject.c
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@ -41,12 +41,20 @@ int
PyFrame_GetLineNumber(PyFrameObject *f)
{
assert(f != NULL);
if (f->f_lineno != 0) {
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;
}
}
if (f->f_lineno > 0) {
return f->f_lineno;
}
else {
return PyUnstable_InterpreterFrame_GetLine(f->f_frame);
}
return PyUnstable_InterpreterFrame_GetLine(f->f_frame);
}
static PyObject *

62
Python/instrumentation.c
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@ -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 */

1
Python/legacy_tracing.c
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@ -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;