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gh-107674: Lazy load line number to improve performance of tracing #118127

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Merged
markshannon merged 4 commits into from
Apr 29, 2024
Merged

gh-107674: Lazy load line number to improve performance of tracing #118127

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af1ed33
Lazy load f_lineno to improve performance of tracing
gaogaotiantian Apr 20, 2024
6acff3d
📜🤖 Added by blurb_it.
blurb-it[bot] Apr 20, 2024
a6cee96
Fix the lineno cache issue
gaogaotiantian Apr 20, 2024
4fecbd4
early return if calculation fails
gaogaotiantian Apr 26, 2024
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Fix the lineno cache issue
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@gaogaotiantian
gaogaotiantian committed Apr 20, 2024
commit a6cee96faf8bf079564160e8ba9f573fd131fe8b
13 changes: 11 additions & 2 deletions Objects/frameobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -41,10 +41,19 @@ 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;
}
}

if (f->f_lineno > 0) {
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@markshannon markshannon Apr 26, 2024

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If f->f_lineno == 0 we end up recalculating the line number, so if PyUnstable_InterpreterFrame_GetLine() returns -1 it will get called twice.

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@gaogaotiantian gaogaotiantian Apr 26, 2024

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Yeah that makes sense.

return f->f_lineno;
}
return f->f_lineno;
return PyUnstable_InterpreterFrame_GetLine(f->f_frame);
}

static PyObject *
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10 changes: 5 additions & 5 deletions Python/instrumentation.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1228,9 +1228,9 @@ _Py_call_instrumentation_line(PyThreadState *tstate, _PyInterpreterFrame* frame,
int line = 0;

if (line_delta == COMPUTED_LINE_LINENO_CHANGE) {
// We know the line number must changed, don't need to calculate the
// line number for now because we might not need it.
line = 0;
// 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);
Expand Down Expand Up @@ -1269,7 +1269,7 @@ _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 == 0 && line_delta > COMPUTED_LINE) {
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.
*/
Expand All @@ -1292,7 +1292,7 @@ _Py_call_instrumentation_line(PyThreadState *tstate, _PyInterpreterFrame* frame,
goto done;
}

if (line == 0) {
if (line == -1) {
/* Need to calculate the line number now for monitoring events */
line = compute_line(code, i, line_delta);
}
Expand Down