cpython/Lib/profiling/sampling/cli.py at main · python/cpython · GitHub

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"""Command-line interface for the sampling profiler."""

import argparse

import importlib.util

import locale

import os

import re

import selectors

import socket

import subprocess

import sys

import time

import webbrowser

from contextlib import nullcontext

from .errors import SamplingUnknownProcessError, SamplingModuleNotFoundError, SamplingScriptNotFoundError

from .sample import sample, sample_live, dump_stack, _is_process_running

from .dump import print_stack_dump

from .pstats_collector import PstatsCollector

from .stack_collector import CollapsedStackCollector, FlamegraphCollector, DiffFlamegraphCollector

from .heatmap_collector import HeatmapCollector

from .gecko_collector import GeckoCollector

from .jsonl_collector import JsonlCollector

from .binary_collector import BinaryCollector

from .binary_reader import BinaryReader

from .constants import (

MICROSECONDS_PER_SECOND,

PROFILING_MODE_ALL,

PROFILING_MODE_WALL,

PROFILING_MODE_CPU,

PROFILING_MODE_GIL,

PROFILING_MODE_EXCEPTION,

SORT_MODE_NSAMPLES,

SORT_MODE_TOTTIME,

SORT_MODE_CUMTIME,

SORT_MODE_SAMPLE_PCT,

SORT_MODE_CUMUL_PCT,

SORT_MODE_NSAMPLES_CUMUL,

)

try:

from ._child_monitor import ChildProcessMonitor

except ImportError:

# _remote_debugging module not available on this platform (e.g., WASI)

ChildProcessMonitor = None

try:

from .live_collector import LiveStatsCollector

except ImportError:

LiveStatsCollector = None

class CustomFormatter(

argparse.ArgumentDefaultsHelpFormatter,

argparse.RawDescriptionHelpFormatter,

"""Custom formatter that combines default values display with raw description formatting."""

pass

class DiffFlamegraphAction(argparse.Action):

"""Custom action for --diff-flamegraph that sets both format and baseline path."""

def __call__(self, parser, namespace, values, option_string=None):

namespace.format = 'diff_flamegraph'

namespace.diff_baseline = values

_HELP_DESCRIPTION = """Sample a process's stack frames and generate profiling data.

Examples:

# Run and profile a script

`python -m profiling.sampling run script.py arg1 arg2`

# Attach to a running process

`python -m profiling.sampling attach 1234`

# Dump a running process's current stack

`python -m profiling.sampling dump 1234`

# Live interactive mode for a script

`python -m profiling.sampling run --live script.py`

# Live interactive mode for a running process

`python -m profiling.sampling attach --live 1234`

Use `python -m profiling.sampling <command> --help` for command-specific help."""

# Constants for socket synchronization

_SYNC_TIMEOUT_SEC = 15.0

_PROCESS_KILL_TIMEOUT_SEC = 5.0

_READY_MESSAGE = b"ready"

_RECV_BUFFER_SIZE = 1024

_BINARY_PROFILE_HEADER_SIZE = 64

_BINARY_PROFILE_MAGICS = (b"HCAT", b"TACH")

# Format configuration

FORMAT_EXTENSIONS = {

"pstats": "pstats",

"collapsed": "txt",

"flamegraph": "html",

"diff_flamegraph": "html",

"gecko": "json",

"heatmap": "html",

"jsonl": "jsonl",

"binary": "bin",

}

COLLECTOR_MAP = {

"pstats": PstatsCollector,

"collapsed": CollapsedStackCollector,

"flamegraph": FlamegraphCollector,

"diff_flamegraph": DiffFlamegraphCollector,

"gecko": GeckoCollector,

"heatmap": HeatmapCollector,

"jsonl": JsonlCollector,

"binary": BinaryCollector,

}

BROWSER_COMPATIBLE_FORMATS = ("flamegraph", "diff_flamegraph", "heatmap")

def _setup_child_monitor(args, parent_pid):

# Build CLI args for child profilers (excluding --subprocesses to avoid recursion)

child_cli_args = _build_child_profiler_args(args)

# Build output pattern

output_pattern = _build_output_pattern(args)

return ChildProcessMonitor(

pid=parent_pid,

cli_args=child_cli_args,

output_pattern=output_pattern,

)

def _get_child_monitor_context(args, pid):

if getattr(args, 'subprocesses', False):

return _setup_child_monitor(args, pid)

return nullcontext()

def _build_child_profiler_args(args):

child_args = []

# Sampling options

hz = MICROSECONDS_PER_SECOND // args.sample_interval_usec

child_args.extend(["-r", str(hz)])

if args.duration is not None:

child_args.extend(["-d", str(args.duration)])

if args.all_threads:

child_args.append("-a")

if args.realtime_stats:

child_args.append("--realtime-stats")

if args.native:

child_args.append("--native")

if not args.gc:

child_args.append("--no-gc")

if args.opcodes:

child_args.append("--opcodes")

if args.async_aware:

child_args.append("--async-aware")

async_mode = getattr(args, 'async_mode', 'running')

if async_mode != "running":

child_args.extend(["--async-mode", async_mode])

# Mode options

mode = getattr(args, 'mode', 'wall')

if mode != "wall":

child_args.extend(["--mode", mode])

# Format options (skip pstats as it's the default)

if args.format == "diff_flamegraph":

child_args.extend(["--diff-flamegraph", args.diff_baseline])

elif args.format != "pstats":

child_args.append(f"--{args.format}")

return child_args

def _build_output_pattern(args):

"""Build output filename pattern for child profilers.

The pattern uses {pid} as a placeholder which will be replaced with the

actual child PID using str.replace(), so user filenames with braces are safe.

"""

if args.outfile:

# User specified output - add PID to filename

base, ext = os.path.splitext(args.outfile)

if ext:

return f"{base}_{{pid}}{ext}"

else:

return f"{args.outfile}_{{pid}}"

else:

# Use default pattern based on format (consistent _ separator)

extension = FORMAT_EXTENSIONS.get(args.format, "txt")

if args.format == "heatmap":

return "heatmap_{pid}"

if args.format == "pstats":

# pstats defaults to stdout, but for subprocesses we need files

return "profile_{pid}.pstats"

return f"{args.format}_{{pid}}.{extension}"

def _parse_mode(mode_string):

"""Convert mode string to mode constant."""

mode_map = {

"wall": PROFILING_MODE_WALL,

"cpu": PROFILING_MODE_CPU,

"gil": PROFILING_MODE_GIL,

"exception": PROFILING_MODE_EXCEPTION,

}

return mode_map[mode_string]

def _check_process_died(process):

"""Check if process died and raise an error with stderr if available."""

if process.poll() is None:

return

# Process died - try to get stderr for error message

stderr_msg = ""

if process.stderr:

try:

stderr_msg = process.stderr.read().decode().strip()

except (OSError, UnicodeDecodeError):

pass

if stderr_msg:

raise RuntimeError(stderr_msg)

raise RuntimeError(f"Process exited with code {process.returncode}")

def _wait_for_ready_signal(sync_sock, process, timeout):

"""Wait for the ready signal from the subprocess, checking for early death."""

deadline = time.monotonic() + timeout

sel = selectors.DefaultSelector()

sel.register(sync_sock, selectors.EVENT_READ)

try:

while True:

_check_process_died(process)

remaining = deadline - time.monotonic()

if remaining <= 0:

raise socket.timeout("timed out")

if not sel.select(timeout=min(0.1, remaining)):

continue

conn, _ = sync_sock.accept()

try:

ready_signal = conn.recv(_RECV_BUFFER_SIZE)

finally:

conn.close()

if ready_signal != _READY_MESSAGE:

raise RuntimeError(f"Invalid ready signal received: {ready_signal!r}")

return

finally:

sel.close()

def _run_with_sync(original_cmd, suppress_output=False):

"""Run a command with socket-based synchronization and return the process."""

# Create a TCP socket for synchronization with better socket options

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sync_sock:

# Set SO_REUSEADDR to avoid "Address already in use" errors

sync_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

sync_sock.bind(("127.0.0.1", 0)) # Let OS choose a free port

sync_port = sync_sock.getsockname()[1]

sync_sock.listen(1)

sync_sock.settimeout(_SYNC_TIMEOUT_SEC)

# Get current working directory to preserve it

cwd = os.getcwd()

# Build command using the sync coordinator

target_args = original_cmd[1:] # Remove python executable

cmd = (

sys.executable,

"-m",

"profiling.sampling._sync_coordinator",

str(sync_port),

cwd,

) + tuple(target_args)

# Start the process with coordinator

# When suppress_output=True (live mode), capture stderr so we can

# report errors if the process dies before signaling ready.

# When suppress_output=False (normal mode), let stderr inherit so

# script errors print to the terminal.

popen_kwargs = {}

if suppress_output:

popen_kwargs["stdin"] = subprocess.DEVNULL

popen_kwargs["stdout"] = subprocess.DEVNULL

popen_kwargs["stderr"] = subprocess.PIPE

process = subprocess.Popen(cmd, **popen_kwargs)

try:

_wait_for_ready_signal(sync_sock, process, _SYNC_TIMEOUT_SEC)

except socket.timeout:

# If we timeout, kill the process and raise an error

if process.poll() is None:

process.terminate()

try:

process.wait(timeout=_PROCESS_KILL_TIMEOUT_SEC)

except subprocess.TimeoutExpired:

process.kill()

process.wait()

raise RuntimeError(

"Process failed to signal readiness within timeout"

)

return process

_RATE_PATTERN = re.compile(r'''

^ # Start of string

( # Group 1: The numeric value

\d+ # One or more digits (integer part)

(?:\.\d+)? # Optional: decimal point followed by digits

) # Examples: "10", "0.5", "100.25"

( # Group 2: Optional unit suffix

hz # "hz" - hertz

| khz # "khz" - kilohertz

| k # "k" - shorthand for kilohertz

)? # Suffix is optional (bare number = Hz)

$ # End of string

''', re.VERBOSE | re.IGNORECASE)

def _parse_sampling_rate(rate_str: str) -> int:

"""Parse sampling rate string to microseconds."""

rate_str = rate_str.strip().lower()

match = _RATE_PATTERN.match(rate_str)

if not match:

raise argparse.ArgumentTypeError(

f"Invalid sampling rate format: {rate_str}. "

"Expected: number followed by optional suffix (hz, khz, k) with no spaces (e.g., 10khz)"

)

number_part = match.group(1)

suffix = match.group(2) or ''

# Determine multiplier based on suffix

suffix_map = {

'hz': 1,

'khz': 1000,

'k': 1000,

}

multiplier = suffix_map.get(suffix, 1)

hz = float(number_part) * multiplier

if hz <= 0:

raise argparse.ArgumentTypeError(f"Sampling rate must be positive: {rate_str}")

interval_usec = int(MICROSECONDS_PER_SECOND / hz)

if interval_usec < 1:

raise argparse.ArgumentTypeError(f"Sampling rate too high: {rate_str}")

return interval_usec

def _add_sampling_options(parser):

"""Add sampling configuration options to a parser."""

sampling_group = parser.add_argument_group("Sampling configuration")

sampling_group.add_argument(

"-r",

"--sampling-rate",

type=_parse_sampling_rate,

default="1khz",

metavar="RATE",

dest="sample_interval_usec",

help="sampling rate (e.g., 10000, 10khz, 10k)",

)

sampling_group.add_argument(

"-d",

"--duration",

type=int,

default=None,

metavar="SECONDS",

help="Sampling duration (default: run to completion)",

)

sampling_group.add_argument(

"-a",

"--all-threads",

action="store_true",

help="Sample all threads in the process instead of just the main thread",

)

sampling_group.add_argument(

"--realtime-stats",

action="store_true",

help="Print real-time sampling statistics (Hz, mean, min, max) during profiling",

)

sampling_group.add_argument(

"--native",

action="store_true",

help='Include artificial `<native>` frames to denote calls to non-Python code',

)

sampling_group.add_argument(

"--no-gc",

action="store_false",

dest="gc",

help='Don\'t include artificial `<GC>` frames to denote active garbage collection',

)

sampling_group.add_argument(

"--opcodes",

action="store_true",

help="Gather bytecode opcode information for instruction-level profiling "

"(shows which bytecode instructions are executing, including specializations).",

)

sampling_group.add_argument(

"--async-aware",

action="store_true",

help="Enable async-aware profiling (uses task-based stack reconstruction)",

)

sampling_group.add_argument(

"--subprocesses",

action="store_true",

help="Also profile subprocesses. Each subprocess gets its own profiler and output file.",

)

sampling_group.add_argument(

"--blocking",

action="store_true",

help="Stop all threads in target process before sampling to get consistent snapshots. "

"Uses thread_suspend on macOS and ptrace on Linux. Adds overhead but ensures memory "

"reads are from a frozen state.",

)

def _add_mode_options(parser):

"""Add mode options to a parser."""

mode_group = parser.add_argument_group("Mode options")

mode_group.add_argument(

"--mode",

choices=["wall", "cpu", "gil", "exception"],

default="wall",

help="Sampling mode: wall (all samples), cpu (only samples when thread is on CPU), "

"gil (only samples when thread holds the GIL), "

"exception (only samples when thread has an active exception). "

"Incompatible with `--async-aware`",

)

mode_group.add_argument(

"--async-mode",

choices=["running", "all"],

default="running",

help='Async profiling mode: "running" (only running task) '

'or "all" (all tasks including waiting). Requires `--async-aware`',

)

def _add_format_options(parser, include_compression=True, include_binary=True):

"""Add output format options to a parser."""

output_group = parser.add_argument_group("Output options")

format_group = output_group.add_mutually_exclusive_group()

format_group.add_argument(

"--pstats",

action="store_const",

const="pstats",

dest="format",

help="Generate pstats output (default)",

)

format_group.add_argument(

"--collapsed",

action="store_const",

const="collapsed",

dest="format",

help="Generate collapsed stack traces for flamegraphs",

)

format_group.add_argument(

"--flamegraph",

action="store_const",

const="flamegraph",

dest="format",

help="Generate interactive HTML flamegraph visualization",

)

format_group.add_argument(

"--gecko",

action="store_const",

const="gecko",

dest="format",

help="Generate Gecko format for Firefox Profiler",

)

format_group.add_argument(

"--heatmap",

action="store_const",

const="heatmap",

dest="format",

help="Generate interactive HTML heatmap visualization with line-level sample counts",

)

format_group.add_argument(

"--diff-flamegraph",

metavar="BASELINE",

action=DiffFlamegraphAction,

help="Generate differential flamegraph comparing current profile to `BASELINE` binary file",

)

format_group.add_argument(

"--jsonl",

action="store_const",

const="jsonl",

dest="format",

help="Generate newline-delimited JSON (JSONL) for programmatic consumers",

)

if include_binary:

format_group.add_argument(

"--binary",

action="store_const",

const="binary",

dest="format",

help="Generate high-performance binary format (use `replay` command to convert)",

)

parser.set_defaults(format="pstats", diff_baseline=None)

if include_compression:

output_group.add_argument(

"--compression",

choices=["auto", "zstd", "none"],

default="auto",

help="Compression for binary format: auto (use zstd if available), zstd, none",

)

output_group.add_argument(

"-o",

"--output",

dest="outfile",

help="Output path (default: `stdout` for `pstats` text; with `-o`, `pstats` is binary). "

"Auto-generated for other formats. For heatmap: directory name (default: `heatmap_PID`)",

)

output_group.add_argument(

"--browser",

action="store_true",

help=(

"Automatically open HTML output "

f"({', '.join('--' + f.replace('_', '-') for f in BROWSER_COMPATIBLE_FORMATS)}) "

"in browser. "

"When using `--subprocesses`, only the main process opens the browser"

)

def _add_pstats_options(parser):

"""Add pstats-specific display options to a parser."""

pstats_group = parser.add_argument_group("pstats format options")

pstats_group.add_argument(

"--sort",

choices=[

"nsamples",

"tottime",

"cumtime",

"sample-pct",

"cumul-pct",

"nsamples-cumul",

"name",

default=None,

help="Sort order for pstats output (default: nsamples)",

)

pstats_group.add_argument(

"-l",

"--limit",

type=int,

default=None,

help="Limit the number of rows in the output (default: 15)",

)

pstats_group.add_argument(

"--no-summary",

action="store_true",

help="Disable the summary section in the pstats output",

)

def _add_dump_options(parser):

"""Add one-shot stack dump options to a parser."""

dump_group = parser.add_argument_group("Dump options")

dump_group.add_argument(

"-a",

"--all-threads",

action="store_true",

help="Dump all threads in the process instead of just the main thread",

)

dump_group.add_argument(

"--native",

action="store_true",

help='Include artificial `<native>` frames to denote calls to non-Python code',

)

dump_group.add_argument(

"--no-gc",

action="store_false",

dest="gc",

help='Don\'t include artificial `<GC>` frames to denote active garbage collection',

)

dump_group.add_argument(

"--opcodes",

action="store_true",

help="Show bytecode opcode names when available.",

)

dump_group.add_argument(

"--async-aware",

action="store_true",

help="Enable async-aware stack reconstruction",

)

dump_group.add_argument(

"--async-mode",

choices=["running", "all"],

default=argparse.SUPPRESS,

help='Async stack mode: "running" (only running task) '

'or "all" (all tasks including waiting, default for dump). '

"Requires `--async-aware`",

)

dump_group.add_argument(

"--blocking",

action="store_true",

help="Stop all threads in target process before dumping the stack.",

)

def _sort_to_mode(sort_choice):

"""Convert sort choice string to SORT_MODE constant."""

sort_map = {

"nsamples": SORT_MODE_NSAMPLES,

"tottime": SORT_MODE_TOTTIME,

"cumtime": SORT_MODE_CUMTIME,

"sample-pct": SORT_MODE_SAMPLE_PCT,

"cumul-pct": SORT_MODE_CUMUL_PCT,

"nsamples-cumul": SORT_MODE_NSAMPLES_CUMUL,

"name": -1,

}

return sort_map.get(sort_choice, SORT_MODE_NSAMPLES)

def _capture_config_from_args(args):

return {

"all_threads": args.all_threads,

"native": args.native,

"gc": args.gc,

"opcodes": args.opcodes,

"blocking": args.blocking,

}

def _create_collector(format_type, sample_interval_usec, skip_idle, opcodes=False,

mode=None, output_file=None, compression='auto',

diff_baseline=None, capture_config=None):

"""Create the appropriate collector based on format type.

Args:

format_type: The output format ('pstats', 'collapsed', 'flamegraph',

'gecko', 'heatmap', 'jsonl', 'binary', 'diff_flamegraph')

sample_interval_usec: Sampling interval in microseconds

skip_idle: Whether to skip idle samples

opcodes: Whether to collect opcode information (only used by gecko format

for creating interval markers in Firefox Profiler)

mode: Profiling mode for collectors that expose it in metadata

output_file: Output file path (required for binary format)

compression: Compression type for binary format ('auto', 'zstd', 'none')

diff_baseline: Path to baseline binary file for differential flamegraph

capture_config: Capture feature mapping for binary profiles and diffs

Returns:

A collector instance of the appropriate type

"""

collector_class = COLLECTOR_MAP.get(format_type)

if collector_class is None:

raise ValueError(f"Unknown format: {format_type}")

if format_type == "diff_flamegraph":

if diff_baseline is None:

raise ValueError("Differential flamegraph requires a baseline file")

if not os.path.exists(diff_baseline):

raise ValueError(f"Baseline file not found: {diff_baseline}")

return collector_class(

sample_interval_usec,

baseline_binary_path=diff_baseline,

skip_idle=skip_idle,

mode=mode,

capture_config=capture_config,

)

# Binary format requires output file and compression

if format_type == "binary":

if output_file is None:

raise ValueError("Binary format requires an output file")

return collector_class(output_file, sample_interval_usec, skip_idle=skip_idle,

compression=compression, mode=mode,

capture_config=capture_config)

# Gecko format never skips idle (it needs both GIL and CPU data)

# and is the only format that uses opcodes for interval markers

if format_type == "gecko":

skip_idle = False

return collector_class(sample_interval_usec, skip_idle=skip_idle, opcodes=opcodes)

if format_type == "jsonl":

return collector_class(

sample_interval_usec, skip_idle=skip_idle, mode=mode

)

return collector_class(sample_interval_usec, skip_idle=skip_idle)

def _generate_output_filename(format_type, pid):

"""Generate output filename based on format and PID.

Args:

format_type: The output format

pid: Process ID

Returns:

Generated filename

"""

extension = FORMAT_EXTENSIONS.get(format_type, "txt")

# For heatmap, use cleaner directory name without extension

if format_type == "heatmap":

return f"heatmap_{pid}"

return f"{format_type}_{pid}.{extension}"

def _open_in_browser(path):

"""Open a file or directory in the default web browser.

Args:

path: File path or directory path to open

For directories (heatmap), opens the index.html file inside.

"""

abs_path = os.path.abspath(path)

# For heatmap directories, open the index.html file

if os.path.isdir(abs_path):

index_path = os.path.join(abs_path, 'index.html')

if os.path.exists(index_path):

abs_path = index_path

else:

print(f"Warning: Could not find index.html in {path}", file=sys.stderr)

return

file_url = f"file://{abs_path}"

try:

webbrowser.open(file_url)

except Exception as e:

print(f"Warning: Could not open browser: {e}", file=sys.stderr)

def _validate_replay_input_file(filename):

"""Validate that the replay input looks like a sampling binary profile."""

try:

with open(filename, "rb") as file:

header = file.read(_BINARY_PROFILE_HEADER_SIZE)

except OSError as exc:

sys.exit(f"Error: Could not read input file {filename}: {exc}")

if (

len(header) < _BINARY_PROFILE_HEADER_SIZE

or header[:4] not in _BINARY_PROFILE_MAGICS

sys.exit(

"Error: Input file is not a binary sampling profile. "

"The replay command only accepts files created with --binary"

)

def _replay_with_reader(args, reader):

"""Replay samples from an open binary reader."""

info = reader.get_info()

interval = info['sample_interval_us']

print(f"Replaying {info['sample_count']} samples from {args.input_file}")

print(f" Sample interval: {interval} us")

print(

" Compression: "

f"{'zstd' if info.get('compression_type', 0) == 1 else 'none'}"

)

collector = _create_collector(

args.format, interval, skip_idle=False,

mode=info.get("mode"),

diff_baseline=args.diff_baseline,

capture_config=info.get("capture_config"),

)

def progress_callback(current, total):

if total > 0:

pct = current / total

bar_width = 40

filled = int(bar_width * pct)

bar = '█' * filled + '░' * (bar_width - filled)

print(

f"\r [{bar}] {pct*100:5.1f}% ({current:,}/{total:,})",

end="",

flush=True,

)

count = reader.replay_samples(collector, progress_callback)

if hasattr(collector, "set_replay_stats"):

collector.set_replay_stats(info)

if hasattr(collector, "set_mode"):

collector.set_mode(info.get("mode"))

print()

if args.format == "pstats":

if args.outfile:

collector.export(args.outfile)

else:

sort_choice = (

args.sort if args.sort is not None else "nsamples"

)

limit = args.limit if args.limit is not None else 15

sort_mode = _sort_to_mode(sort_choice)

collector.print_stats(

sort_mode, limit, not args.no_summary,

info.get("mode") if info.get("mode") is not None

else PROFILING_MODE_WALL

)

else:

filename = (

args.outfile

or _generate_output_filename(args.format, os.getpid())

)

export_ok = collector.export(filename)

# Auto-open browser for HTML output if --browser flag is set

if (

export_ok

and args.format in BROWSER_COMPATIBLE_FORMATS

and getattr(args, 'browser', False)

_open_in_browser(filename)

print(f"Replayed {count} samples")

def _handle_output(collector, args, pid, mode):

"""Handle output for the collector based on format and arguments.

Args:

collector: The collector instance with profiling data

args: Parsed command-line arguments

pid: Process ID (for generating filenames)

mode: Profiling mode used

"""

if args.format == "binary":

# Binary format already wrote to file incrementally, just finalize

collector.export(None)

filename = collector.filename

print(f"Binary profile written to {filename} ({collector.total_samples} samples)")

elif args.format == "pstats":

if args.outfile:

# If outfile is a directory, generate filename inside it

if os.path.isdir(args.outfile):

filename = os.path.join(args.outfile, _generate_output_filename(args.format, pid))

collector.export(filename)

else:

collector.export(args.outfile)

else:

# Print to stdout with defaults applied

sort_choice = args.sort if args.sort is not None else "nsamples"

limit = args.limit if args.limit is not None else 15

sort_mode = _sort_to_mode(sort_choice)

collector.print_stats(

sort_mode, limit, not args.no_summary, mode

)

else:

# Export to file

if args.outfile and os.path.isdir(args.outfile):

# If outfile is a directory, generate filename inside it

filename = os.path.join(args.outfile, _generate_output_filename(args.format, pid))

else:

filename = args.outfile or _generate_output_filename(args.format, pid)

export_ok = collector.export(filename)

# Auto-open browser for HTML output if --browser flag is set

if (

export_ok

and args.format in BROWSER_COMPATIBLE_FORMATS

and getattr(args, 'browser', False)

_open_in_browser(filename)

def _validate_args(args, parser):

"""Validate format-specific options and live mode requirements.

Args:

args: Parsed command-line arguments

parser: ArgumentParser instance for error reporting

"""

command = getattr(args, 'command', None)

if command == "replay":

return

# Check if live mode is available

if hasattr(args, 'live') and args.live and LiveStatsCollector is None:

parser.error(

"Live mode requires the curses module, which is not available."

)

# --subprocesses is incompatible with --live

if hasattr(args, 'subprocesses') and args.subprocesses:

if ChildProcessMonitor is None:

parser.error(

"--subprocesses is not available on this platform "

"(requires _remote_debugging module)."

)

if hasattr(args, 'live') and args.live:

parser.error("--subprocesses is incompatible with --live mode.")

# Async-aware mode is incompatible with options that need thread data.

if getattr(args, 'async_aware', False):

issues = []

if getattr(args, 'native', False):

issues.append("--native")

if not getattr(args, 'gc', True):

issues.append("--no-gc")

if getattr(args, 'format', None) == "binary":

issues.append("--binary")

if hasattr(args, 'mode') and args.mode != "wall":

issues.append(f"--mode={args.mode}")

if hasattr(args, 'all_threads') and args.all_threads:

issues.append("--all-threads")

if issues:

parser.error(

f"Options {', '.join(issues)} are incompatible with --async-aware. "

"Async-aware profiling uses task-based stack reconstruction."

)

# --async-mode requires --async-aware when explicitly set

if not getattr(args, 'async_aware', False):

if command == "dump":

# dump uses SUPPRESS default, so attr only exists if user passed it

if hasattr(args, 'async_mode'):

parser.error("--async-mode requires --async-aware to be enabled.")

elif hasattr(args, 'async_mode') and args.async_mode != "running":

parser.error("--async-mode requires --async-aware to be enabled.")

if command == "dump":

return

# Warn about blocking mode with aggressive sampling intervals

if args.blocking and args.sample_interval_usec < 100:

print(

f"Warning: --blocking with a {args.sample_interval_usec} µs interval will stop all threads "

f"{1_000_000 // args.sample_interval_usec} times per second. "

"Consider using --sampling-rate 1khz or lower to reduce overhead.",

file=sys.stderr

)

# Live mode is incompatible with format options

if hasattr(args, 'live') and args.live:

if args.format != "pstats":

format_flag = f"--{args.format}"

parser.error(

f"--live is incompatible with {format_flag}. Live mode uses a TUI interface."

)

# Live mode is also incompatible with pstats-specific options

issues = []

if args.sort is not None:

issues.append("--sort")

if args.limit is not None:

issues.append("--limit")

if args.no_summary:

issues.append("--no-summary")

if issues:

parser.error(

f"Options {', '.join(issues)} are incompatible with --live. "

"Live mode uses a TUI interface with its own controls."

)

return

# Validate gecko mode doesn't use non-wall mode

if args.format == "gecko" and getattr(args, 'mode', 'wall') != "wall":

parser.error(

"--mode option is incompatible with --gecko. "

"Gecko format automatically includes both GIL-holding and CPU status analysis."

)

# Validate --opcodes is only used with compatible formats

opcodes_compatible_formats = ("live", "gecko", "flamegraph", "diff_flamegraph", "heatmap", "binary")

if getattr(args, 'opcodes', False) and args.format not in opcodes_compatible_formats:

parser.error(

f"--opcodes is only compatible with {', '.join('--' + f for f in opcodes_compatible_formats)}."

)

# Validate pstats-specific options are only used with pstats format

if args.format != "pstats":

issues = []

if args.sort is not None:

issues.append("--sort")

if args.limit is not None:

issues.append("--limit")

if args.no_summary:

issues.append("--no-summary")

if issues:

format_flag = f"--{args.format}"

parser.error(

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