view contrib/showstack.py @ 40925:008f3491dc53

perf: add perfprogress command

I've noticed that progress bars can add significant overhead to tight
loops. Let's add a perf command that attempts to isolate that overhead.

With a default hgrc, iteration over 1M items appears to take ~3.75s on
my machine. Profiling reveals ~28% of time is spent in ui.configbool()
resolving the value of the progress.debug config option.

Even if I set progress.disable=true, execution still takes ~2.60s, with
~59% of the time spent in ui.configbool().

Differential Revision: https://phab.mercurial-scm.org/D5407

# showstack.py - extension to dump a Python stack trace on signal
#
# binds to both SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)
"""dump stack trace when receiving SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)
"""

from __future__ import absolute_import, print_function
import signal
import sys
import traceback

def sigshow(*args):
    sys.stderr.write("\n")
    traceback.print_stack(args[1], limit=10, file=sys.stderr)
    sys.stderr.write("----\n")

def sigexit(*args):
    sigshow(*args)
    print('alarm!')
    sys.exit(1)

def extsetup(ui):
    signal.signal(signal.SIGQUIT, sigshow)
    signal.signal(signal.SIGALRM, sigexit)
    try:
        signal.signal(signal.SIGINFO, sigshow)
    except AttributeError:
        pass