I used my local patch to profile import time.  I think it's useful for
3rd party authors.
For example:

./python -Ximportprofile -c 'import traceback'
    - _codecs 71 [us]
  - codecs 677 [us]
  - encodings.aliases 412 [us]
- encodings 1688 [us]
- encodings.utf_8 250 [us]
- _signal 120 [us]
- encodings.latin_1 281 [us]
    - _weakrefset 301 [us]
  - abc 593 [us]
- io 1032 [us]
  - _locale 100 [us]
- _bootlocale 262 [us]
    - errno 165 [us]
      - _stat 73 [us]
    - stat 270 [us]
      - genericpath 166 [us]
    - posixpath 456 [us]
    - _collections_abc 1798 [us]
  - os 3366 [us]
  - _sitebuiltins 221 [us]
  - sitecustomize 408 [us]
  - usercustomize 168 [us]
- site 5019 [us]
      - _operator 104 [us]
    - operator 873 [us]
    - keyword 177 [us]
      - _heapq 188 [us]
    - heapq 399 [us]
    - itertools 140 [us]
    - reprlib 224 [us]
    - _collections 89 [us]
  - collections 3009 [us]
      - _functools 76 [us]
        - collections.abc 267 [us]
      - types 592 [us]
      - weakref 499 [us]
    - functools 1726 [us]
        - enum 894 [us]
          - _sre 97 [us]
            - sre_constants 428 [us]
          - sre_parse 849 [us]
        - sre_compile 1267 [us]
        - copyreg 200 [us]
      - re 3035 [us]
      - token 222 [us]
    - tokenize 4660 [us]
  - linecache 6592 [us]
- traceback 10108 [us]

What does the "[us]" mean?

It means μs (micro seconds), in ASCII.

On 2017年9月20日(水) 3:35 Brett Cannon <report@bugs.python.org> wrote:

>
> Brett Cannon added the comment:
>
> What does the "[us]" mean?
>
> ----------
> nosy: +brett.cannon
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue31415>
> _______________________________________
>
-- 
Inada Naoki <songofacandy@gmail.com>

If this proposition be accepted I would want to see not only cumulated times, but also pure times, without time of nested imports.

I guess this feature doesn't work correctly with threading.

Ah, OK. Then I wouldn't put it in square brackets as it seems to suggest it's somehow disconnected from the number.

> If this proposition be accepted I would want to see not only cumulated times, but also pure times, without time of nested imports.

It can be calculated by script.
I don't want to add more complexity to import.c.

> I guess this feature doesn't work correctly with threading.

Yes, it should be documented.
And that's reason why I don't want to support time without nested import.
Stack management is difficult than inc/dec integer in multi threading case.

> Stack management is difficult than inc/dec integer in multi threading case.

Actually it is easy. You need just one global integer accumulator and a local variable for keeping a temporary copy of it.

> Actually it is easy. You need just one global integer accumulator and a local variable for keeping a temporary copy of it.

You're right!  I updated my pull request.
See current output: https://gist.github.com/methane/185d75a3c8da762d85317dd95918a623

Guido, is this something you want?

Historically, we've shown a lot of restraint when it comes to adding command-line options.  

Also, I'm not sure we want to induce people to start moving their imports inside function calls.  Just because we sometimes adopt constipated programming practices in the standard library doesn't mean we think everyone should do it.  (This is doubly true because sometimes the savings is a false savings if the import eventually occurs downstream and because there is currently work being done on lazy imports that would make the technique irrelevant).

@rhettinger
> Guido, is this something you want?

I think it is useful given how much debate there has been around startup time in various contexts (not just pure interpreter startup time but also startup time when using specific libraries, packages or applications).

> Historically, we've shown a lot of restraint when it comes to adding
> command-line options.

But this is hardly a new command-line option; -X already exists. I think it's reasonable to add it here.

> Also, I'm not sure we want to induce people to start moving their imports
> inside function calls. [...]

That's a big leap from collecting the data to suggesting a specific solution. I don't think that making it harder to get the data really is the right approach to discouraging a debatable practice (plus, there are many situations where the practice *is* useful -- just as there are many situations where it's counterproductive). Consenting adults.

Naoki, is it possible to separate out how much of this is I/O vs CPU time?

If the I/O dominates, optimizations tend toward zipimports, faster drives, disk caching etc.  If the CPU time is dominant, different techniques are used (lazy evaluation, splitting-out parts of a package, etc).

I don't have any good idea for it.

I usually run `python -X importtime -c 'import functools'` several times to ensure pyc files are created and it is cached by OS.

On Linux, `strace -c` and `time` command can be used.
But I don't know cross platform way to do it.

$ strace -c python -c 'import asyncio'
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
  0.00    0.000000           0       244           read
  0.00    0.000000           0       160         2 open
  0.00    0.000000           0       161           close
  0.00    0.000000           0       527        46 stat
  0.00    0.000000           0       266           fstat
  0.00    0.000000           0        16           lstat
  0.00    0.000000           0       114         6 lseek
  0.00    0.000000           0       109           mmap

$ /usr/bin/time python -c 'import asyncio'
0.12user 0.00system 0:00.13elapsed 98%CPU (0avgtext+0avgdata 17004maxresident)k
0inputs+0outputs (0major+2613minor)pagefaults 0swaps

+1 for an option to profile import time.

I have a minor complain: The output format is not machine-friendly, which makes it harder to perform automatic analysis. I created #31574 / PR3749 to add dtrace probes.

how can I make it more machine readable?

On 2017年9月25日(月) 19:39 Christian Heimes <report@bugs.python.org> wrote:

>
> Christian Heimes added the comment:
>
> +1 for an option to profile import time.
>
> I have a minor complain: The output format is not machine-friendly, which
> makes it harder to perform automatic analysis. I created #31574 / PR3749 to
> add dtrace probes.
>
> ----------
> nosy: +christian.heimes
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue31415>
> _______________________________________
>
-- 
Inada Naoki <songofacandy@gmail.com>

The output in PR 3765 partially duplicates the output of the -v option.

> The output in PR 3765 partially duplicates the output of the -v option.

Right. But the idea is to be able to use "grep 'import time:'" to only extract importtime logs. "-v" logs different kind of informations.

Related: https://bugs.python.org/issue31574

New changeset 1a87de7fcfa3c19f08e29047337c350b4a32b259 by INADA Naoki in branch 'master':
bpo-31415: Add `-X importtime` option (GH-3490)
https://github.com/python/cpython/commit/1a87de7fcfa3c19f08e29047337c350b4a32b259

Thank you Naoki for this nice enhancement! Tooling always help to take smart decisions on optimizations.

This is pretty useless on Windows because you are using a clock with 15-16 milli (not micro) second resolution on Windows.  Before Victor introduced time.perf_counter, with decent behavior on all systems, timeit used different time module functions on Windows and *nix because the two different functions had such different behavior on the two systems.  I believe it used time.clock on Windows (1 second resolution of *nix?) and time.time otherwise (.016 sec resolution on Windows).  

Time.monotonic seems to be based on time.time as it has the same low resolution on Windows.  Run something like

for i in range(1000): time.monotonic()

and you will see identical times except for 1 or 2 jumps of .016.  So the C equivalent or time.clock or time.perf_counter is needed on Windows.  Victor can advise as he knows this better than me.

An example of nearly useless output, with 15-16 millisecond resolution.

f:\dev\3x>python -X importtime -c "import idlelib.pyshell"
Running Debug|Win32 interpreter...
import time: self [us] | cumulative | imported package
import time:         0 |          0 |     _codecs
import time:         0 |          0 |   codecs
import time:         0 |          0 |   encodings.aliases
import time:     15000 |      15000 | encodings
import time:         0 |          0 | encodings.utf_8
import time:         0 |          0 | _signal
import time:         0 |          0 | encodings.latin_1
import time:         0 |          0 |     _weakrefset
import time:         0 |          0 |   abc
import time:         0 |          0 | io
import time:         0 |          0 |       _stat
import time:         0 |          0 |     stat
import time:         0 |          0 |       genericpath
import time:         0 |          0 |     ntpath
import time:         0 |          0 |     _collections_abc
import time:     16000 |      16000 |   os
import time:         0 |          0 |   _sitebuiltins
import time:         0 |          0 |   sitecustomize
import time:         0 |          0 |   usercustomize
import time:     16000 |      32000 | site
import time:         0 |          0 |   idlelib
import time:         0 |          0 |       types
import time:         0 |          0 |       _collections
import time:         0 |          0 |     enum
import time:     16000 |      16000 |     _tkinter
import time:         0 |          0 |     tkinter.constants
import time:         0 |          0 |         _sre
import time:         0 |          0 |           sre_constants
import time:         0 |          0 |         sre_parse
import time:         0 |          0 |       sre_compile
import time:         0 |          0 |         _functools
import time:         0 |          0 |             _operator
import time:         0 |          0 |           operator
import time:         0 |          0 |           keyword
import time:         0 |          0 |             _heapq
import time:         0 |          0 |           heapq
import time:         0 |          0 |           itertools
import time:     15000 |      15000 |           reprlib
import time:         0 |      15000 |         collections
import time:         0 |      15000 |       functools
import time:         0 |          0 |       _locale
import time:         0 |          0 |       copyreg
import time:     16000 |      31000 |     re
import time:         0 |      47000 |   tkinter
import time:         0 |          0 |     tkinter.commondialog
import time:     16000 |      16000 |   tkinter.messagebox
import time:         0 |          0 |           token
import time:         0 |          0 |         tokenize
import time:         0 |          0 |       linecache
import time:         0 |          0 |     traceback
import time:     15000 |      15000 |       __future__
import time:         0 |      15000 |     codeop
import time:         0 |      15000 |   code
import time:         0 |          0 |       time
import time:         0 |          0 |       signal
import time:         0 |          0 |       warnings
import time:         0 |          0 |       errno
import time:         0 |          0 |       threading
import time:         0 |          0 |       msvcrt
import time:         0 |          0 |       _winapi
import time:     16000 |      16000 |     subprocess
import time:     16000 |      32000 |   platform
import time:         0 |          0 |     _socket
import time:         0 |          0 |       collections.abc
import time:         0 |          0 |       math
import time:         0 |          0 |       select
import time:         0 |          0 |     selectors
import time:     15000 |      15000 |   socket
import time:     16000 |      16000 |       configparser
import time:         0 |          0 |       tkinter.font
import time:         0 |          0 |       _bootlocale
import time:         0 |          0 |       encodings.cp1252
import time:     31000 |      47000 |     idlelib.config
import time:         0 |          0 |     idlelib.delegator
import time:     63000 |     110000 |   idlelib.colorizer
import time:         0 |          0 |         posixpath
import time:         0 |          0 |       fnmatch
import time:         0 |          0 |           _ast
import time:     15000 |      15000 |         ast
import time:         0 |          0 |             _opcode
import time:         0 |          0 |           opcode
import time:         0 |          0 |         dis
import time:     16000 |      16000 |           importlib
import time:         0 |      16000 |         importlib.machinery
import time:         0 |      31000 |       inspect
import time:         0 |      31000 |     bdb
import time:         0 |          0 |     tkinter.ttk
import time:         0 |          0 |     idlelib.macosx
import time:         0 |          0 |     idlelib.scrolledlist
import time:         0 |          0 |     idlelib.windows
import time:         0 |      31000 |   idlelib.debugger
import time:     16000 |      16000 |   idlelib.debugger_r
import time:         0 |          0 |     importlib.abc
import time:         0 |          0 |       contextlib
import time:         0 |          0 |     importlib.util
import time:         0 |          0 |       _string
import time:     15000 |      15000 |     string
import time:         0 |          0 |       shlex
import time:         0 |          0 |         zlib
import time:         0 |          0 |           _compression
import time:         0 |          0 |           _bz2
import time:     16000 |      16000 |         bz2
import time:         0 |          0 |           _lzma
import time:         0 |          0 |         lzma
import time:         0 |          0 |         pwd
import time:         0 |          0 |         grp
import time:         0 |      16000 |       shutil
import time:         0 |      16000 |     webbrowser
import time:     15000 |      15000 |     tkinter.simpledialog
import time:         0 |          0 |       tkinter.colorchooser
import time:         0 |          0 |       idlelib.config_key
import time:         0 |          0 |           weakref
import time:         0 |          0 |               org
import time:         0 |          0 |             org.python
import time:         0 |          0 |           org.python.core
import time:         0 |          0 |         copy
import time:         0 |          0 |       idlelib.dynoption
import time:         0 |          0 |           tkinter.dialog
import time:     16000 |      16000 |         tkinter.filedialog
import time:         0 |      16000 |       idlelib.query
import time:         0 |          0 |       idlelib.tabbedpages
import time:         0 |          0 |       idlelib.textview
import time:         0 |          0 |           idlelib.multicall
import time:         0 |          0 |         idlelib.autocomplete_w
import time:         0 |          0 |           idlelib.pyparse
import time:     16000 |      16000 |         idlelib.hyperparser
import time:     15000 |      31000 |       idlelib.autocomplete
import time:         0 |          0 |       idlelib.codecontext
import time:         0 |          0 |       idlelib.parenmatch
import time:         0 |          0 |       idlelib.paragraph
import time:         0 |      47000 |     idlelib.configdialog
import time:         0 |          0 |       idlelib.searchbase
import time:         0 |          0 |       idlelib.searchengine
import time:         0 |          0 |     idlelib.grep
import time:     16000 |      16000 |           html.entities
import time:         0 |      16000 |         html
import time:         0 |          0 |         _markupbase
import time:     16000 |      32000 |       html.parser
import time:         0 |      32000 |     idlelib.help
import time:         0 |          0 |     idlelib.help_about
import time:         0 |          0 |     idlelib.replace
import time:         0 |          0 |     idlelib.search
import time:         0 |          0 |       idlelib.redirector
import time:         0 |          0 |     idlelib.percolator
import time:     15000 |      15000 |     idlelib.undo
import time:         0 |          0 |             _hashlib
import time:         0 |          0 |             _blake2
import time:         0 |          0 |             _sha3
import time:         0 |          0 |           hashlib
import time:         0 |          0 |             _bisect
import time:         0 |          0 |           bisect
import time:         0 |          0 |           _random
import time:         0 |          0 |         random
import time:         0 |          0 |       tempfile
import time:     16000 |      16000 |       locale
import time:         0 |      16000 |     idlelib.iomenu
import time:         0 |          0 |     idlelib.mainmenu
import time:         0 |          0 |     idlelib.statusbar
import time:         0 |          0 |     idlelib.autoexpand
import time:     15000 |      15000 |       textwrap
import time:         0 |          0 |       idlelib.calltip_w
import time:         0 |      15000 |     idlelib.calltips
import time:         0 |          0 |     idlelib.rstrip
import time:         0 |          0 |     idlelib.zoomheight
import time:         0 |     171000 |   idlelib.editor
import time:         0 |          0 |   idlelib.filelist
import time:         0 |          0 |   idlelib.outwin
import time:         0 |          0 |         _struct
import time:         0 |          0 |       struct
import time:         0 |          0 |       _compat_pickle
import time:         0 |          0 |           org
import time:         0 |          0 |         org.python
import time:         0 |          0 |       org.python.core
import time:         0 |          0 |       _pickle
import time:         0 |          0 |     pickle
import time:         0 |          0 |     queue
import time:     16000 |      16000 |     socketserver
import time:     16000 |      32000 |   idlelib.rpc
import time:         0 |          0 |     idlelib.debugobj_r
import time:         0 |          0 |         idlelib.tree
import time:         0 |          0 |       idlelib.debugobj
import time:         0 |          0 |     idlelib.stackviewer
import time:         0 |          0 |   idlelib.run
import time:         0 |          0 |   idlelib.history
import time:     30000 |     515000 | idlelib.pyshell

https://github.com/python/cpython/blob/27c623c845dd6e4b8e1782666ca3a956636da266/Modules/timemodule.c#L80-L112

time module has perf_counter implementation based on QueryPerformanceCounter().

Could we change PyTime_GetMonotonicClock implementation to use it on Windows?

I don't want to so much code to import.c.  But if pytime.c has nice clock
for fine grained monotonic performance counter, I want to use it in
import.c.

> Could we change PyTime_GetMonotonicClock implementation to use it on Windows?

No. See the PEP 418 for the rationale.

But we could add a _PyTime_GetPerfCounter() to Python/pytime.c.

New changeset a997c7b434631f51e00191acea2ba6097691e859 by Victor Stinner in branch 'master':
bpo-31415: Add _PyTime_GetPerfCounter() and use it for -X importtime (#3936)
https://github.com/python/cpython/commit/a997c7b434631f51e00191acea2ba6097691e859

Why global _PyTime_GetWinPerfCounterWithInfo() is needed at all? It seems to me that _PyTime_GetPerfCounterWithInfo() can be used instead. Smaller API is better.

_PyTime_GetPerfCounter() is a simple wrapper around _PyTime_GetPerfCounterWithInfo() and is used only in one place. Getting rid of it will simplify C API too.

> Why global _PyTime_GetWinPerfCounterWithInfo() is needed at all? It seems to me that _PyTime_GetPerfCounterWithInfo() can be used instead. Smaller API is better.

I chose to expose _PyTime_GetWinPerfCounterWithInfo() to make my change as small as possible.

I didn't want to break the old time.clock() clock by mistake.

By the way, time.clock() is deprecated since Python 3.3. It's maybe time to drop it?

Ok, the feature was implemented, the Windows clock resolution was fixed as well. It's time to close this issue.

If you still have concerns about import time, see open discussions on the python-dev mailing list, or open new issues ;-)

Thanks again Naoki INADA for this nice and useful feature!

The importtime option is cached only if it is set. If it is not set (the common case), it is not cached.

PR 4138 makes it be cached in the common case and improves errors handling.

Does it worth enough?
I didn't think it's worth enough because import will be much slower than one dict lookup.

> I didn't think it's worth enough because import will be much slower than one dict lookup.

I don't care much of performance. For the consistency with other environment variables, I like to only read the environment variable once ("at startup"), and not do it each time.

Xoptions is not environment variable.

Some modules are imported before xoptions are parsed.
So negative cache for xoptions is little more complex than
negative cache for environment variable.

I like this a lot and while the issue is still open, I'm piggybacking my PR 4240 on this one.

I have a use case for enabling this feature via environment variable, so PR 4240 adds PYTHONPROFILEIMPORTTIME which also enables this feature.

We build our tools using pex, which hardcodes the shebang at the top of the zip file.  This isn't easily changed, and clearly we wouldn't want to enable -X importtime everywhere.  When we have startup performance issues, I want to be able to tell people (or set it up in our CI) to set the environment variable and collect the data for analysis.  This is much easier than tweaking the shebang or invoking the zip with an explicit command.  Also, there are potential gotchas with loading too much up on the shebang line (IIRC, there are line length limits and/or multiple option limits for shebangs, e.g. if we wanted to have both -I and -X).

I haven't fixed the initialization check problem that serhiy.storchaka points out, since that's addressed by PR 4138.  But maybe I should fold that change into mine.

New changeset 700d2e4755921d6c339ff20dacecde1aea64de34 by Barry Warsaw in branch 'master':
bpo-31415: Support PYTHONPROFILEIMPORTTIME envvar equivalent to -X importtime (#4240)
https://github.com/python/cpython/commit/700d2e4755921d6c339ff20dacecde1aea64de34

When adding environment variable option, it should be documented in
man page and `python -h`.

On Nov 2, 2017, at 22:50, INADA Naoki <report@bugs.python.org> wrote:
> 
> When adding environment variable option, it should be documented in
> man page and `python -h`.

I thought about that, but the problem is that none of the -X options are documented in the —help output.  So do we only document the ones (e.g. importtime) that have an environment variable version, or do we now have to document them all?

I opted to document PYTHONPROFILEIMPORTTIME only in the cmdline documentation.

> I didn't think it's worth enough because import will be much slower than one dict lookup.

I agree. The main value of my patch is handling possible (but very unlike) errors. Implementing negative value caching adds not many lines to the existing code and additional error handling.

But now, after adding the environment variable, do we still need the -X option? From a user side I don't see much difference between specifying an option and an environment variable, but the code for handling the environment variable is much simpler.

On Nov 3, 2017, at 11:05, Serhiy Storchaka <report@bugs.python.org> wrote:
> 
> But now, after adding the environment variable, do we still need the -X option? From a user side I don't see much difference between specifying an option and an environment variable, but the code for handling the environment variable is much simpler.

It’s a good question.  I guess in the limited amount of time I’ve used the feature so far, I find it kind of nice to be able to type `python -X importtime` when doing general import profiling.  The use case for the environment variable is more compelling IMHO which is why I really wanted to add it.  I suppose typing `PYTHONPROFILEIMPORTTIME=x python` isn’t *too* onerous, even if it is kind of a weird long mashed together word.

I suppose I’m -0 on removing the -X option, and +0 on adding the negative cache.

> `PYTHONPROFILEIMPORTTIME=x python` isn’t *too* onerous

It does not work on Windows.

C:\Users\Terry>PYTHONPROFILEIMPORTTIME=x python
'PYTHONPROFILEIMPORTTIME' is not recognized as an internal or external command, operable program or batch file.

Does it set the EV for the entire session (which one likely would not want), or just the one command (which has no Windows equivalent that I know of)?  Please leave the easily remembered and typed option.

Note that with environment variable you get more information.

$ ./python -X importtime -c pass
import time: self [us] | cumulative | imported package
import time:        88 |         88 |     _codecs
import time:       789 |        876 |   codecs
import time:       602 |        602 |   encodings.aliases
import time:       809 |       2287 | encodings
...

$ PYTHONPROFILEIMPORTTIME=1 ./python -c pass
import time: self [us] | cumulative | imported package
import time:      3133 |       3133 | _frozen_importlib_external
import time:       371 |        371 | zipimport
import time:       327 |        327 |     _codecs
import time:      2656 |       2982 |   codecs
import time:      1821 |       1821 |   encodings.aliases
import time:      2604 |       7406 | encodings
...

On Windows you can create a 2-line bat-file that sets the environment variable and runs Python.

On Nov 3, 2017, at 14:41, Serhiy Storchaka <report@bugs.python.org> wrote:
> 
> Note that with environment variable you get more information.

Fun!

On Nov 3, 2017, at 14:23, Terry J. Reedy <report@bugs.python.org> wrote:
> 
> Does it set the EV for the entire session (which one likely would not want), or just the one command (which has no Windows equivalent that I know of)?  Please leave the easily remembered and typed option.

On *nix, this sets the environment variable for just this process.

I'm +1 to remove -X option.
Supporting both form makes code ugly and benefit is too small.
And +1 to negative cache too.   It's simple for environment varianle.

One benefit (or drawback, depending on how you see it) of the -X option is that it wouldn't propagate to child processes spawned by multiprocessing.  See _args_from_interpreter_flags() in Lib/subprocess.py.

More generally, the idea that we should remove a command line option because there's an environment variable sounds dubious to me.  Should we do the same for all command-line options?  The faulthandler module can be enabled either using the `PYTHONFAULTHANDLER` environment variable or by specifying `-X faulthandler` on the command line.

The only serious reason I can imagine would be that the -X option has a significant maintenance cost.

(and Terry is right that environment variables can be significantly more annoying on Windows)

Okay, given the non-propagation and Windows issues.  I'm -1 on removing -X, +1 on fixing the negative cache.

> with environment variable you get more information.

For timing package import time, such as for idlelib.pyshell, rather than bare python startup time, the extra information is just a bit more noise to ignore.

The importtime output is sent to stderr.  Should this be documented?  It is important because displaying results immediately on command prompt rather than redirecting to a file adds about .07 seconds to the total time reported for pyshell, whether I use debug or normal binaries.  The relative variation between repeated runs (about 1%) also seems less with redirection to a file.

On Nov 4, 2017, at 14:29, Terry J. Reedy <report@bugs.python.org> wrote:

> The importtime output is sent to stderr.  Should this be documented?

Yes. :)

New changeset 088929cf62fa22c06f6a44e25915abce9048a545 by Serhiy Storchaka in branch 'master':
bpo-31415: Improve error handling and caching of the importtime option. (#4138)
https://github.com/python/cpython/commit/088929cf62fa22c06f6a44e25915abce9048a545

I think there is nothing left to do for this issue, so I'm closing it.

FYI I'm working on the Py_Main() function in bpo-32030. My latest PR (PR 4412) moves the code to parse -X importtime and PYTHONPROFILEIMPORTTIME into Py_Main(), to group all functions parsing the command line arguments and environment variables.

With this change, the "importtime" option is now checked before the very first "Python" function call.

The new code doesn't use the sys module anymore to parse -X options, and so break the dependency between "importtime", the import machinery and the sys module.

I just updated tuna [1] to support import time profiles as well.
Install with
```
pip install tuna
```
and use with
```
python -X importprofile yourfile.py 2> import.log
tuna import.log
```
See screenshot for example output.

Cheers,
Nico

[1] https://github.com/nschloe/tuna

New changeset 29624e769c5c3c1e59c6acc8b69383ead53e8a9f by Victor Stinner in branch 'main':
bpo-31415: importtime was made by Inada Naoki (GH-31875)
https://github.com/python/cpython/commit/29624e769c5c3c1e59c6acc8b69383ead53e8a9f

New changeset 9f1587e8d3f18729a0982774c6c4409472cbd9e3 by Miss Islington (bot) in branch '3.10':
bpo-31415: importtime was made by Inada Naoki (GH-31875)
https://github.com/python/cpython/commit/9f1587e8d3f18729a0982774c6c4409472cbd9e3

New changeset 73943ce7d31595d152dc01bf0008b37c802c0d3b by Miss Islington (bot) in branch '3.9':
bpo-31415: importtime was made by Inada Naoki (GH-31875)
https://github.com/python/cpython/commit/73943ce7d31595d152dc01bf0008b37c802c0d3b