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Optimize python tracing debugger performance #3356

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112 changes: 64 additions & 48 deletions python/helpers/pydev/_pydevd_bundle/pydevd_pep_669_tracing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -302,6 +302,16 @@ def _should_enable_line_events_for_code(frame, code, filename, info, will_be_sto
for breakpoint in breakpoints_for_file.values():
# will match either global or some function
if breakpoint.func_name in ('None', curr_func_name):
if breakpoint.func_name == 'None' and curr_func_name != '':
# Module-level breakpoints (func_name='None') should not enable line
# tracing for all functions. Check if breakpoint is within this function's
# line range to avoid unnecessary tracing.
first_line = code.co_firstlineno
# Get last line number from code object (Python 3.11+)
lines = [line for _, _, line in code.co_lines() if line is not None]
last_line = max(lines) if lines else first_line
if not (first_line <= breakpoint.line <= last_line):
continue
has_breakpoint_in_frame = True
# New breakpoint was processed -> stop tracing monitoring.events.INSTRUCTION
remove_breakpoint(breakpoint)
Expand All @@ -320,7 +330,10 @@ def _should_enable_line_events_for_code(frame, code, filename, info, will_be_sto
else:
global_cache_frame_skips[frame_cache_key] = 0

if can_skip and not has_breakpoint_in_frame:
# Performance fix: Only enable line tracing if this frame has a breakpoint.
# Without this check, all functions in a file would be traced whenever
# any breakpoint exists in the file, causing significant slowdown.
if not has_breakpoint_in_frame:
return False

return True
Expand All @@ -347,21 +360,14 @@ def _clear_run_state(info):
# ENDIF


def _get_top_level_frame():
f_unhandled = _getframe()

while f_unhandled:
filename = f_unhandled.f_code.co_filename
name = splitext(basename(filename))[0]
if name == 'pydevd':
if f_unhandled.f_code.co_name == '_exec':
break
elif name == 'threading':
if f_unhandled.f_code.co_name == '_bootstrap_inner':
break
f_unhandled = f_unhandled.f_back

return f_unhandled
def _is_top_level_frame(frame):
"""Check if frame is a top-level entry point (O(1) instead of walking stack)."""
name = splitext(basename(frame.f_code.co_filename))[0]
if name == 'pydevd' and frame.f_code.co_name == '_exec':
return True
if name == 'threading' and frame.f_code.co_name == '_bootstrap_inner':
return True
return False


def _stop_on_unhandled_exception(exc_info, py_db, thread):
Expand Down Expand Up @@ -512,6 +518,21 @@ def py_start_callback(code, instruction_offset):
return

try:
# Performance optimization: Check cache before expensive operations.
# Checking the cache first avoids unnecessary disposed checks, thread liveness
# checks, path normalization, and file type checks for already-seen frames.
info = thread_info.additional_info
if info is None:
return

pydev_step_cmd = info.pydev_step_cmd
is_stepping = pydev_step_cmd != -1

if not is_stepping:
frame_cache_key = _make_frame_cache_key(code)
if frame_cache_key in global_cache_skips:
return monitoring.DISABLE

if py_db.pydb_disposed:
return monitoring.DISABLE

Expand All @@ -526,18 +547,8 @@ def py_start_callback(code, instruction_offset):
if py_db.asyncio_analyser is not None:
py_db.asyncio_analyser.log_event(frame)

frame_cache_key = _make_frame_cache_key(code)

info = thread_info.additional_info
if info is None:
return

pydev_step_cmd = info.pydev_step_cmd
is_stepping = pydev_step_cmd != -1

if not is_stepping and frame_cache_key in global_cache_skips:
# print('skipped: PY_START (cache hit)', frame_cache_key, frame.f_lineno, code.co_name)
return
if is_stepping:
frame_cache_key = _make_frame_cache_key(code)

abs_path_real_path_and_base = _get_abs_path_real_path_and_base_from_frame(frame)
filename = abs_path_real_path_and_base[1]
Expand All @@ -557,7 +568,9 @@ def py_start_callback(code, instruction_offset):
breakpoints_for_file = (py_db.breakpoints.get(filename)
or py_db.has_plugin_line_breaks)
if not breakpoints_for_file and not is_stepping:
return
# Cache frames without breakpoints to avoid repeated checks.
global_cache_skips[frame_cache_key] = 1
return monitoring.DISABLE

if py_db.plugin and py_db.has_plugin_line_breaks:
args = (py_db, filename, info, thread_info.thread)
Expand Down Expand Up @@ -628,7 +641,7 @@ def py_start_callback(code, instruction_offset):
_enable_return_tracing(code)
else:
global_cache_skips[frame_cache_key] = 1
return
return monitoring.DISABLE

except SystemExit:
return monitoring.DISABLE
Expand Down Expand Up @@ -854,8 +867,6 @@ def py_line_callback(code, line_number):
def py_raise_callback(code, instruction_offset, exception):
# print('PY_RAISE %s %s %s' % (code.co_name, code.co_filename, exception))

exc_info = (type(exception), exception, exception.__traceback__)

try:
py_db = GlobalDebuggerHolder.global_dbg
except AttributeError:
Expand All @@ -864,6 +875,15 @@ def py_raise_callback(code, instruction_offset, exception):
if py_db is None:
return

has_exception_breakpoints = (py_db.break_on_caught_exceptions
or py_db.has_plugin_exception_breaks
or py_db.stop_on_failed_tests)
if not has_exception_breakpoints:
return

# Only do expensive work if exception breakpoints are actually enabled
exc_info = (type(exception), exception, exception.__traceback__)

try:
try:
thread_info = _thread_local_info.thread_info
Expand All @@ -878,25 +898,21 @@ def py_raise_callback(code, instruction_offset, exception):
return

frame = _getframe(1)
if frame is _get_top_level_frame():
if _is_top_level_frame(frame):
_stop_on_unhandled_exception(exc_info, py_db, thread)
return

has_exception_breakpoints = (py_db.break_on_caught_exceptions
or py_db.has_plugin_exception_breaks
or py_db.stop_on_failed_tests)
if has_exception_breakpoints:
args = (
py_db,
_get_abs_path_real_path_and_base_from_frame(frame)[1],
info, thread,
global_cache_skips,
global_cache_frame_skips
)
should_stop, frame = should_stop_on_exception(
args, frame, 'exception', exc_info)
if should_stop:
handle_exception(args, frame, 'exception', exc_info)
args = (
py_db,
_get_abs_path_real_path_and_base_from_frame(frame)[1],
info, thread,
global_cache_skips,
global_cache_frame_skips
)
should_stop, frame = should_stop_on_exception(
args, frame, 'exception', exc_info)
if should_stop:
handle_exception(args, frame, 'exception', exc_info)
except KeyboardInterrupt:
_clear_run_state(info)
raise
Expand Down