[boot-time] [RFC] analyze-initcall-debug.py - a tool to analyze the initcall debug output

[Francesco Valla <francesco@valla.it>]

Dear fellow boot time optimizers,

following the first boot time SIG meeting, which I lurked with much pleasure
(but didn't participate to, as I was a bit in awe among such authorities), I'd
like to introduce myself with code rather than a presentation or resume.

Here is a python script which can analyze a dmesg output with initcall_debug
option enabled and extract some useful information. It can for example be used
to analyze the output of the grab-boot-data.sh tool that Tim presented on this
list [1] just a few days ago.

Usage is very simple, as the output of dmesg can be piped directly to it:

    dmesg | analyze-initcall-debug.py

If no option is specified, it outputs a brief summary, like the following one
(obtained on my Beagleplay):

1758 drivers has been initialized, of which 1758 before userspace
119 probes happened outside of the init of their driver
0 deferred probes pending
---
Top 10 init/probes durations:
 * 30200000.dss -> 523002us
 * deferred_probe_initcall -> 487483us
 * fd00000.gpu -> 162859us
 * 8000f00.mdio -> 142521us
 * 44043000.system-controller -> 71390us
 * 2-004c -> 71178us
 * 40900000.crypto -> 59350us
 * 8000000.ethernet -> 58419us
 * 44043000.system-controller:clock-controller -> 56599us
 * jent_mod_init -> 52140us

A more complete output, reporting all durations as well as statuses, impact of
probe deferral and so on, can be produced either in HTML or Markdown format,
using respectively the --html or --markdown parameters.

Note: it hasn't (yet?) been used in a "production" environment, as I never
found the motivation to write a script and always analyzed manually the
initcall_debug output.

If you have time to take a look, please tell me what you think and what
can be added.

Thank you!

Regards,
Francesco

[1] https://lore.kernel.org/linux-embedded/MW5PR13MB5632F54DCBDA0C74370E531FFD5C2@MW5PR13MB5632.namprd13.prod.outlook.com/

--- analyze-initcall-debug.py script follows ---

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
This script can be used to analyze a Linux kernel dmesg output when the
initcall_debug command line output is used. It extract various information,
such as init durations, impact of probe deferral and so on.
"""

import argparse
import re
import sys

ERRCODE_PROBE_DEFER = 517

parser = argparse.ArgumentParser()

parser.add_argument('--dmesg', nargs='?', type=argparse.FileType('r'),
                    default=sys.stdin)
parser.add_argument('--html', action='store_true')
parser.add_argument('--markdown', action='store_true')
args = parser.parse_args()

class Run:
    def __init__(self, start_time:int, end_time:int = -1, duration:int = 0, retval:int = 0):
        self._start_time = start_time
        self._end_time = end_time
        self._duration = duration
        self._retval = retval
        self._ended = (end_time >= 0)

    @property
    def start_time(self) -> int:
        return self._start_time

    @property
    def end_time(self) -> int:
        return self._end_time

    @end_time.setter
    def end_time(self, time:int):
        self._end_time = time
        self._ended = True

    @property
    def duration(self) -> int:
        return self._duration

    @duration.setter
    def duration(self, time:int):
        self._duration = time

    @property
    def retval(self) -> int:
        return self._retval

    @retval.setter
    def retval(self, val:int):
        self._retval = val

    @property
    def running(self) -> bool:
        return (not self._ended or abs(self.retval) == ERRCODE_PROBE_DEFER)

    @property
    def failed(self) -> bool:
        return ((self.retval != 0) and not self.running)


class Entity:
    def __init__(self, name:str, start_time:int = 0, end_time:int = 0, duration:int = 0, retval:int = 0):
        self._name = name
        self._runs = [ Run(start_time, end_time, duration, retval) ]

    @property
    def name(self) -> str:
        return self._name

    @property
    def first_start_time(self) -> int:
        return self._runs[0].start_time

    @property
    def last_start_time(self) -> int:
        return self._runs[-1].start_time

    @property
    def first_end_time(self) -> int:
        return self._runs[0].end_time

    @property
    def last_end_time(self) -> int:
        return self._runs[-1].end_time

    @property
    def duration(self) -> int:
        return sum([ r.duration for r in self._runs ])

    @property
    def wasted_time(self) -> int:
        return sum([ r.duration for r in filter(lambda x: x.failed or abs(x.retval) == ERRCODE_PROBE_DEFER, self._runs) ])

    @property
    def retval(self) -> int:
        return self._runs[-1].retval

    @property
    def failed(self) -> bool:
        return self._runs[-1].failed

    @property
    def running(self) -> bool:
        return self._runs[-1].running

    @property
    def deferred_probe_pending(self) -> bool:
        return (abs(self._runs[-1].retval) == ERRCODE_PROBE_DEFER)

    @property
    def num_deferred_probes(self) -> int:
        return len(list(filter(lambda r: abs(r.retval) == ERRCODE_PROBE_DEFER, self._runs)))

    def addStart(self, start_time: int):
        self._runs.append( Run(start_time) )

    def addEnd(self, end_time:int = 0, duration:int = 0, retval:int = 0):
        self._runs[-1].end_time = end_time
        self._runs[-1].duration = duration
        self._runs[-1].retval = retval

    def addRun(self, start_time: int, end_time:int = 0, duration:int = 0, retval:int = 0):
        self._runs.append( Run(start_time, end_time, duration, retval) )


class Driver (Entity):
    def __init__(self, name: str, start_time: int):
        super().__init__(name, start_time)

    def addInit(self, init_time: int):
        self.addStart(init_time)

    def addReturn(self, return_time: int, duration: int, retval: int):
        self.addEnd(return_time, duration, retval)


class Probe (Entity):
    def __init__(self, name: str, return_time: int, duration: int, retval: int):
        super().__init__(name, return_time, return_time, duration, retval)


class Init (Entity):
    def __init__(self, name: str, start_time: int):
        super().__init__(name, start_time)


# Regex for 'calling' messages
# "[    0.466115] calling  pci_sysfs_init+0x0/0xa8 @ 1"
calling_prog = re.compile(r'\[([0-9\s]+\.[0-9]+)\] calling  ([0-9a-zA-Z_]+)\+(0x[0-9a-fA-F]+\/0x[0-9a-fA-F]+) @ ([0-9]+)')

# Regex for 'initcall ... returned' messages
# "[    0.466115] initcall pci_sysfs_init+0x0/0xa8 returned 0 after 5 usecs"
returned_prog = re.compile(r'\[([0-9\s]+\.[0-9]+)\] initcall ([0-9a-zA-Z_]+)\+(0x[0-9a-fA-F]+\/0x[0-9a-fA-F]+) returned ([\-0-9]+) after ([0-9]+) usecs')

# Regex for 'probe ... returned' messages
# "[    0.466115] probe of cpufreq-dt returned 517 after 140 usec"
probe_prog = re.compile(r'\[([0-9\s]+\.[0-9]+)\] probe of ([0-9a-zA-Z_\-\.\:@]+) returned ([\-0-9]+) after ([0-9]+) usecs')

# Regex for
# "[    1.060329] Run /sbin/init as init process"
init_prog = re.compile(r'\[([0-9\s]+\.[0-9]+)\] Run ([/0-9a-zA-Z_]+) as init process')

drivers = list()
probes = list()
init = None

# Extract data from dmesg
for line in args.dmesg:
    match = calling_prog.match(line)
    if match is not None:
        time = float(match.group(1)) * float(10^6)
        name = str(match.group(2))
        try:
            time = float(match.group(1)) * float(10^6)
            name = str(match.group(2))
        except Exception as e:
            print(f'Failed parsing line "{line.rstrip()}" as call')
            raise e
        else:
            for d in filter(lambda x: x.name == name, drivers):
                d.addInit(time)
                break
            else:
                drivers.append(Driver(name, time))
        finally:
            continue

    match = returned_prog.match(line)
    if match is not None:
        try:
            time = float(match.group(1)) * float(10^6)
            name = str(match.group(2))
            retval = int(match.group(4))
            duration = int(match.group(5))
        except:
            print(f'Failed parsing line "{line.rstrip()}" as call return')
        else:
            for d in filter(lambda x: x.name == name, drivers):
                d.addReturn(time, duration, retval)
                break
            else:
                print(f'Detected return for driver {name}, for which an init was never recorded')
        finally:
            continue

    match = probe_prog.match(line)
    if match is not None:
        try:
            time = float(match.group(1)) * float(10^6)
            name = str(match.group(2))
            retval = int(match.group(3))
            duration = int(match.group(4))
        except:
            print(f'Failed parsing line "{line.rstrip()}" as probe return')
        else:
            for d in filter(lambda x: x.name == name, probes):
                d.addRun(time, time, duration, retval)
                break
            else:
                probes.append(Probe(name, time, duration, retval))
        finally:
            continue

    if init is None:
        match = init_prog.match(line)
        if match is not None:
            try:
                time = float(match.group(1)) * float(10^6)
                name = str(match.group(2))
            except:
                print(f'Failed parsing line "{line.rstrip()}" as probe return')
            else:
                init = Init(name, time)
            finally:
                continue

if args.markdown:
    print('| Name | Type [^1] | Status [^2] | Duration (us) | Before userspace | Num deferred probes | Time spent in failed inits (us) |')
    print('| -----| --------- | ----------- | ------------- | ---------------- | ------------------- | ------------------------------- |')
    for d in sorted(filter(lambda k: k.duration > 0, drivers + probes), key=lambda k: k.duration, reverse=True):
        etype = 'I' if d in drivers else 'P'
        run_status = 'D' if d.deferred_probe_pending else 'R' if d.running else f'F({abs(d.retval)})' if d.failed else 'K'
        before_init = 'Y' if d.last_start_time < init.last_start_time else 'N'
        print(f'| {d.name} | {etype} | {run_status} | {d.duration} | {before_init} | {d.num_deferred_probes} | {d.wasted_time} |')
    print('[^1]: I=Init function, P=device Probe')
    print('[^2]: D=Deferred probe pending, R=still Running, F(N)=Failed (with errcode N), K=init oK')
elif args.html:
    print(
'''
<!DOCTYPE HTML>
<html>
<head>
  <meta charset="utf-8" />
  <title>Initcall analysis</title>
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <style>
    table, th, td {
      border: 1px solid;
    }
  </style>
</head>
<body>

<table>
  <tr>
    <th>Name</th>
    <th>Type <a href="#note1">[1]</a></th>
    <th>Status <a href="#note2">[2]</a></th>
    <th>Duration (us)</th>
    <th>Before userspace</th>
    <th>Num deferred probes</th>
    <th>Time spent in failed inits (us)</th>
  </tr>''')

    for d in sorted(filter(lambda k: k.duration > 0, drivers + probes), key=lambda k: k.duration, reverse=True):
        etype = 'I' if d in drivers else 'P'
        run_status = 'D' if d.deferred_probe_pending else 'R' if d.running else f'F({abs(d.retval)})' if d.failed else 'K'
        before_init = 'Y' if d.last_start_time < init.last_start_time else 'N'
        print(
f'''
  <tr>
    <td>{d.name}</td>
    <td>{etype}</td>
    <td>{run_status}</td>
    <td>{d.duration}</td>
    <td>{before_init}</td>
    <td>{d.num_deferred_probes}</td>
    <td>{d.wasted_time}</td>
  </tr>''')

    print(
'''
</table>
<p id="note1">[1] I=Init function, P=device Probe</p>
<p id="note2">[2] D=Deferred probe pending, R=still Running, F(N)=Failed (with errcode N), K=init oK</p>
</body>
</html>
''')

else:
    print(f'{len(drivers)} drivers has been initialized, of which {len(list(filter(lambda d: d.last_start_time < init.last_start_time, drivers)))} before userspace')
    print(f'{len(probes)} probes happened outside of the init of their driver')

    print(f'{len(list(filter(lambda d: d.deferred_probe_pending, drivers + probes)))} deferred probes pending')

    print('---')

    print('Top 10 init/probes durations:')
    for d in sorted(filter(lambda k: k.duration > 0, drivers + probes), key=lambda k: k.duration, reverse=True)[0:10]:
        print(f' * {d.name} -> {d.duration}us')