Cold start issue within the infra with limited resource

[denismakogon]

Long story short

I've been working on a UDS HTTP server and found that aiohttp has pretty sane API to make it work.
However, with some testing being done I've found out that aiohttp has a problem of the cold start. Within the constraint-bound infrastructure, imagine a docker container with the following resources:

--cpu-quota=10000 --cpu-period=100000 --cpu-shares=128 --memory=128m --kernel-memory=128m --memory-swap=128m

aiohttp UDS HTTP server consumes unfortunate amount of time for the cold start, here's the statistics of the imports from Python 3.7 with PYTHONPROFILEIMPORTTIME=1:

import time: self [us] | cumulative | imported package
import time:       168 |        168 | zipimport
import time:      1150 |       1150 | _frozen_importlib_external
import time:        91 |         91 |     _codecs
import time:      4804 |       4894 |   codecs
import time:     88056 |      88056 |   encodings.aliases
import time:      4840 |      97789 | encodings
import time:      1731 |       1731 | encodings.utf_8
import time:       204 |        204 | _signal
import time:      1318 |       1318 | encodings.latin_1
import time:       153 |        153 |     _abc
import time:      1621 |       1774 |   abc
import time:     92601 |      94375 | io
import time:       176 |        176 |   _locale
import time:      1681 |       1857 | _bootlocale
import time:       160 |        160 |       _stat
import time:     96817 |      96977 |     stat
import time:      1960 |       1960 |       genericpath
import time:      3918 |       5877 |     posixpath
import time:     87176 |      87176 |     _collections_abc
import time:      6476 |     196505 |   os
import time:      1223 |       1223 |   _sitebuiltins
import time:       262 |        262 |   sitecustomize
import time:       258 |        258 |   usercustomize
import time:      6408 |     204654 | site
import time:       147 |        147 |           _operator
import time:    188664 |     188811 |         operator
import time:      1541 |       1541 |         keyword
import time:       392 |        392 |           _heapq
import time:      5235 |       5627 |         heapq
import time:       212 |        212 |         itertools
import time:      2494 |       2494 |         reprlib
import time:     91121 |      91121 |         _collections
import time:     94050 |     383852 |       collections
import time:       609 |        609 |       collections.abc
import time:       968 |        968 |         concurrent
import time:       229 |        229 |             time
import time:        77 |         77 |                   _functools
import time:     94078 |      94155 |                 functools
import time:     92610 |      92610 |                       types
import time:      7071 |      99680 |                     enum
import time:       112 |        112 |                       _sre
import time:      1558 |       1558 |                         sre_constants
import time:     93503 |      95061 |                       sre_parse
import time:    101855 |     197027 |                     sre_compile
import time:      1860 |       1860 |                     copyreg
import time:     99112 |     397677 |                   re
import time:      1531 |       1531 |                   token
import time:      6687 |     405894 |                 tokenize
import time:      2139 |     502187 |               linecache
import time:      2896 |     505083 |             traceback
import time:     97892 |      97892 |             warnings
import time:      2698 |       2698 |               _weakrefset
import time:      5511 |       8209 |             weakref
import time:        78 |         78 |               _string
import time:     87842 |      87920 |             string
import time:      6537 |       6537 |             threading
import time:       144 |        144 |             atexit
import time:    187032 |     893042 |           logging
import time:      4603 |     897645 |         concurrent.futures._base
import time:       991 |     899603 |       concurrent.futures
import time:       592 |        592 |         _socket
import time:       517 |        517 |           math
import time:     86062 |      86062 |           select
import time:      5099 |      91677 |         selectors
import time:       229 |        229 |         errno
import time:      9377 |     101874 |       socket
import time:     96501 |      96501 |         signal
import time:      1561 |       1561 |         _posixsubprocess
import time:    103890 |     201951 |       subprocess
import time:      1874 |       1874 |         _ssl
import time:       413 |        413 |             _struct
import time:       572 |        984 |           struct
import time:     93528 |      93528 |           binascii
import time:      4376 |      98888 |         base64
import time:     95527 |     196288 |       ssl
import time:      1503 |       1503 |       asyncio.constants
import time:       338 |        338 |               _opcode
import time:     85969 |      86307 |             opcode
import time:      5353 |      91660 |           dis
import time:      2079 |       2079 |             importlib
import time:      1011 |       3089 |           importlib.machinery
import time:    299486 |     394235 |         inspect
import time:      2993 |       2993 |           asyncio.format_helpers
import time:      2143 |       5135 |         asyncio.base_futures
import time:      1787 |       1787 |         asyncio.log
import time:      3146 |     404301 |       asyncio.coroutines
import time:      2476 |       2476 |           _contextvars
import time:     88070 |      90546 |         contextvars
import time:      1539 |       1539 |           asyncio.base_tasks
import time:      7506 |       9045 |         _asyncio
import time:      5551 |     105141 |       asyncio.events
import time:      3540 |       3540 |       asyncio.futures
import time:     85365 |      85365 |       asyncio.protocols
import time:      2511 |       2511 |         asyncio.transports
import time:      5479 |       7989 |       asyncio.sslproto
import time:      5688 |       5688 |       asyncio.tasks
import time:      9556 |    2407255 |     asyncio.base_events
import time:      5543 |       5543 |     asyncio.locks
import time:      2308 |       2308 |     asyncio.runners
import time:      2708 |       2708 |     asyncio.queues
import time:     97048 |      97048 |     asyncio.streams
import time:      2853 |       2853 |     asyncio.subprocess
import time:     85194 |      85194 |       asyncio.base_subprocess
import time:    102495 |     102495 |       asyncio.selector_events
import time:      7549 |     195238 |     asyncio.unix_events
import time:     84536 |    2797487 |   asyncio
import time:        94 |         94 |       gc
import time:       386 |        480 |     uvloop.includes
import time:       540 |        540 |     uvloop._patch
import time:       476 |        476 |       backports_abc
import time:     78295 |      78295 |       uvloop._noop
import time:      1092 |       1092 |           _queue
import time:      3299 |       4391 |         queue
import time:      4589 |       8979 |       concurrent.futures.thread
import time:    104049 |     191798 |     uvloop.loop
import time:      1360 |     194177 |   uvloop
import time:      1127 |       1127 |   fdk.constants
import time:      1440 |       1440 |   fdk.log
import time:      2368 |       2368 |           numbers
import time:      1916 |       4284 |         _decimal
import time:       594 |       4877 |       decimal
import time:       396 |        396 |         _datetime
import time:     93148 |      93544 |       datetime
import time:       489 |      98909 |     ujson
import time:     10406 |      10406 |             platform
import time:       374 |      10779 |           multidict._compat
import time:     91622 |      91622 |           multidict._abc
import time:       244 |        244 |             multidict._istr
import time:       452 |        452 |             multidict._multidict_base
import time:       725 |       1420 |           multidict._multidict
import time:       442 |     104262 |         multidict
import time:       591 |     104852 |       aiohttp.hdrs
import time:      1666 |       1666 |           _hashlib
import time:       307 |        307 |           _blake2
import time:     91593 |      91593 |           _sha3
import time:      2317 |      95881 |         hashlib
import time:       418 |        418 |               _json
import time:      1444 |       1861 |             json.scanner
import time:      2734 |       4595 |           json.decoder
import time:     96686 |      96686 |           json.encoder
import time:      2425 |     103704 |         json
import time:      2727 |       2727 |           contextlib
import time:     96681 |      99407 |         typing
import time:      1320 |       1320 |           __future__
import time:       181 |        181 |                     org
import time:       392 |        573 |                   org.python
import time:       344 |        917 |                 org.python.core
import time:      2826 |       3742 |               copy
import time:       378 |        378 |               attr._config
import time:       510 |        510 |                   _ctypes
import time:      1538 |       1538 |                   ctypes._endian
import time:     88577 |      90624 |                 ctypes
import time:      1040 |      91664 |               attr._compat
import time:       577 |        577 |               attr.exceptions
import time:      3989 |     100349 |             attr._make
import time:       964 |     101312 |           attr.converters
import time:       333 |        333 |           attr.filters
import time:     96471 |      96471 |           attr.validators
import time:       836 |        836 |           attr._funcs
import time:      3746 |     204016 |         attr
import time:     96483 |      96483 |           ipaddress
import time:      1121 |       1121 |             urllib
import time:    103727 |     104847 |           urllib.parse
import time:       285 |        285 |             idna.package_data
import time:       588 |        588 |               idna.idnadata
import time:       358 |        358 |                 _bisect
import time:      2667 |       3025 |               bisect
import time:       395 |        395 |               unicodedata
import time:       518 |        518 |               idna.intranges
import time:     93101 |      97625 |             idna.core
import time:       746 |      98656 |           idna
import time:       395 |        395 |             yarl._quoting
import time:      1199 |       1593 |           yarl.quoting
import time:      2338 |     303915 |         yarl
import time:      1243 |       1243 |         aiohttp.client_exceptions
import time:      2740 |       2740 |             http
import time:     93976 |      96715 |           http.cookies
import time:       634 |        634 |                 email
import time:      1347 |       1347 |                   email.errors
import time:      2516 |       2516 |                       email.quoprimime
import time:      1045 |       1045 |                       email.base64mime
import time:      1733 |       1733 |                           quopri
import time:     87119 |      88852 |                         email.encoders
import time:      3090 |      91941 |                       email.charset
import time:    100394 |     195895 |                     email.header
import time:       285 |        285 |                         _random
import time:     94047 |      94331 |                       random
import time:    102339 |     102339 |                           locale
import time:     98757 |     201096 |                         calendar
import time:      5651 |     206746 |                       email._parseaddr
import time:      3892 |     304968 |                     email.utils
import time:      5218 |     506081 |                   email._policybase
import time:     99983 |     607410 |                 email.feedparser
import time:     85240 |     693283 |               email.parser
import time:      1155 |       1155 |                 uu
import time:      2514 |       2514 |                 email._encoded_words
import time:      1065 |       1065 |                 email.iterators
import time:     92932 |      97665 |               email.message
import time:     12377 |      12377 |                 html.entities
import time:    180954 |     193330 |               html
import time:      1155 |       1155 |                   fnmatch
import time:       833 |        833 |                   zlib
import time:       992 |        992 |                     _compression
import time:       953 |        953 |                     _bz2
import time:     89428 |      91372 |                   bz2
import time:       669 |        669 |                     _lzma
import time:      3602 |       4270 |                   lzma
import time:       275 |        275 |                   pwd
import time:       553 |        553 |                   grp
import time:    102263 |     200719 |                 shutil
import time:      5895 |     206614 |               tempfile
import time:      9513 |    1200403 |             cgi
import time:      2482 |       2482 |               shlex
import time:     87735 |      90217 |             netrc
import time:       208 |        208 |                 nt
import time:       954 |        954 |                 nt
import time:       605 |        605 |                 nt
import time:    100771 |     102536 |               ntpath
import time:    101934 |     204469 |             pathlib
import time:    103125 |     103125 |               http.client
import time:      1429 |       1429 |                 urllib.response
import time:      2376 |       3804 |               urllib.error
import time:    191045 |     297972 |             urllib.request
import time:       916 |        916 |             async_timeout
import time:       860 |        860 |             aiohttp.abc
import time:     93244 |      93244 |             aiohttp.log
import time:       358 |        358 |             aiohttp._helpers
import time:    104458 |    1992893 |           aiohttp.helpers
import time:       150 |        150 |                 winreg
import time:     86282 |      86431 |               mimetypes
import time:      4959 |       4959 |               socketserver
import time:     11136 |     102525 |             http.server
import time:     98074 |      98074 |             aiohttp.http_exceptions
import time:       331 |        331 |                 aiohttp.base_protocol
import time:       106 |        106 |                   aiohttp.multidict
import time:       474 |        579 |                 aiohttp._http_writer
import time:      1874 |       2783 |               aiohttp.http_writer
import time:       764 |        764 |                 aiohttp.typedefs
import time:      2497 |       3261 |               aiohttp.streams
import time:       425 |        425 |               brotli
import time:       144 |        144 |                 backports_abc
import time:       822 |        965 |               aiohttp._http_parser
import time:      4569 |      12001 |             aiohttp.http_parser
import time:       328 |        328 |               aiohttp._websocket
import time:     97916 |      98243 |             aiohttp.http_websocket
import time:     90324 |     401166 |           aiohttp.http
import time:       208 |        208 |               _uuid
import time:      9808 |      10016 |             uuid
import time:      1020 |       1020 |             aiohttp.payload
import time:     85342 |      96376 |           aiohttp.multipart
import time:       635 |        635 |           aiohttp.formdata
import time:       297 |        297 |           cchardet
import time:       385 |        385 |             chardet.compat
import time:       399 |        399 |                 chardet.enums
import time:       346 |        346 |                 chardet.charsetprober
import time:       581 |       1325 |               chardet.charsetgroupprober
import time:       289 |        289 |                 chardet.codingstatemachine
import time:       352 |        352 |                 chardet.escsm
import time:       886 |       1526 |               chardet.escprober
import time:       456 |        456 |               chardet.latin1prober
import time:       335 |        335 |                   chardet.mbcssm
import time:       674 |       1009 |                 chardet.utf8prober
import time:       305 |        305 |                   chardet.mbcharsetprober
import time:       522 |        522 |                     chardet.euctwfreq
import time:       402 |        402 |                     chardet.euckrfreq
import time:       768 |        768 |                     chardet.gb2312freq
import time:      1250 |       1250 |                     chardet.big5freq
import time:       627 |        627 |                     chardet.jisfreq
import time:     91953 |      95520 |                   chardet.chardistribution
import time:       680 |        680 |                   chardet.jpcntx
import time:      1332 |      97836 |                 chardet.sjisprober
import time:       540 |        540 |                 chardet.eucjpprober
import time:       437 |        437 |                 chardet.gb2312prober
import time:       456 |        456 |                 chardet.euckrprober
import time:       517 |        517 |                 chardet.cp949prober
import time:       338 |        338 |                 chardet.big5prober
import time:       318 |        318 |                 chardet.euctwprober
import time:      1401 |     102848 |               chardet.mbcsgroupprober
import time:       278 |        278 |                 chardet.sbcharsetprober
import time:       422 |        422 |                 chardet.langcyrillicmodel
import time:       534 |        534 |                 chardet.langgreekmodel
import time:       455 |        455 |                 chardet.langbulgarianmodel
import time:       749 |        749 |                 chardet.langthaimodel
import time:     85346 |      85346 |                 chardet.langhebrewmodel
import time:      1350 |       1350 |                 chardet.hebrewprober
import time:      1227 |       1227 |                 chardet.langturkishmodel
import time:      1021 |      91379 |               chardet.sbcsgroupprober
import time:      2158 |     199689 |             chardet.universaldetector
import time:       748 |        748 |             chardet.version
import time:       803 |     201624 |           chardet
import time:      7880 |    2797583 |         aiohttp.client_reqrep
import time:       286 |        286 |           aiohttp.client_proto
import time:       316 |        316 |           aiohttp.locks
import time:       170 |        170 |             aiodns
import time:       668 |        838 |           aiohttp.resolver
import time:     91319 |      92757 |         aiohttp.connector
import time:      1957 |       1957 |         aiohttp.client_ws
import time:      1335 |       1335 |             _compat_pickle
import time:     83611 |      83611 |                 org
import time:       127 |      83738 |               org.python
import time:        71 |      83809 |             org.python.core
import time:       684 |        684 |             _pickle
import time:     12772 |      98598 |           pickle
import time:      3240 |     101838 |         aiohttp.cookiejar
import time:     95985 |      95985 |         aiohttp.tcp_helpers
import time:       142 |        142 |                   aiohttp.collections
import time:       214 |        356 |                 aiohttp.collections.abc
import time:      1090 |       1446 |               aiohttp._frozenlist
import time:       548 |       1994 |             aiohttp.frozenlist
import time:       388 |       2381 |           aiohttp.signals
import time:     10661 |      13042 |         aiohttp.tracing
import time:    187869 |    4099192 |       aiohttp.client
import time:      1046 |       1046 |       aiohttp.payload_streamer
import time:       320 |        320 |           gunicorn
import time:       123 |        443 |         gunicorn.config
import time:      1008 |       1450 |       aiohttp.worker
import time:     95296 |    4301835 |     aiohttp
import time:    186432 |     186432 |         gettext
import time:     13800 |     200231 |       argparse
import time:       642 |        642 |             aiohttp.web_response
import time:     92020 |      92661 |           aiohttp.web_exceptions
import time:       425 |        425 |             aiohttp.web_fileresponse
import time:      3469 |       3894 |           aiohttp.web_urldispatcher
import time:       403 |      96958 |         aiohttp.web_middlewares
import time:     99315 |      99315 |         aiohttp.web_request
import time:      1089 |       1089 |           aiohttp.web_protocol
import time:      1030 |       2119 |         aiohttp.web_server
import time:      1841 |     200231 |       aiohttp.web_app
import time:      3288 |       3288 |       aiohttp.web_routedef
import time:      1739 |       1739 |       aiohttp.web_runner
import time:      1817 |       1817 |       aiohttp.web_ws
import time:      1630 |     408936 |     aiohttp.web
import time:     85227 |      85227 |       xml
import time:      1446 |      86673 |     xml.etree
import time:      2154 |       2154 |       xml.etree.ElementPath
import time:       400 |        400 |         pyexpat
import time:       693 |       1093 |       _elementtree
import time:     99974 |     103220 |     xml.etree.ElementTree
import time:      2159 |       2159 |         iso8601.iso8601
import time:       466 |       2624 |       iso8601
import time:       382 |        382 |         fdk.headers
import time:       502 |        883 |       fdk.context
import time:       449 |        449 |         fdk.response
import time:       251 |        699 |       fdk.errors
import time:       661 |       4867 |     fdk.runner
import time:      1687 |    5006123 |   fdk.http_stream
import time:       810 |    8001160 | fdk

As you may see, aiohttp takes at least 8 seconds to start, which is not quite expected. The validation system that ensures that a UDS server is up and running expects it to become active within 2-4 seconds at maximum within given constraints, but aiohttp takes at least 8 seconds to start.
The thing is, if I would use native tools like asyncio with some custom HTTP routine, i can speed up cold start up to 1.8 seconds:

import time: self [us] | cumulative | imported package
import time:       117 |        117 | zipimport
import time:       749 |        749 | _frozen_importlib_external
import time:        71 |         71 |     _codecs
import time:       579 |        650 |   codecs
import time:       482 |        482 |   encodings.aliases
import time:       967 |       2097 | encodings
import time:       252 |        252 | encodings.utf_8
import time:       134 |        134 | _signal
import time:    101907 |     101907 | encodings.latin_1
import time:        74 |         74 |     _abc
import time:       805 |        879 |   abc
import time:       902 |       1780 | io
import time:        77 |         77 |       _stat
import time:       323 |        400 |     stat
import time:       244 |        244 |       genericpath
import time:       710 |        953 |     posixpath
import time:      1455 |       1455 |     _collections_abc
import time:       911 |       3717 |   os
import time:       609 |        609 |   _sitebuiltins
import time:       253 |        253 |   sitecustomize
import time:        89 |         89 |   usercustomize
import time:      1531 |       6197 | site
import time:       171 |        171 |           _operator
import time:       950 |       1121 |         operator
import time:       446 |        446 |         keyword
import time:       354 |        354 |           _heapq
import time:       597 |        951 |         heapq
import time:       190 |        190 |         itertools
import time:       446 |        446 |         reprlib
import time:       137 |        137 |         _collections
import time:      2290 |       5578 |       collections
import time:       481 |        481 |       collections.abc
import time:       268 |        268 |         concurrent
import time:       165 |        165 |             time
import time:       136 |        136 |                   _functools
import time:      1097 |       1233 |                 functools
import time:       435 |        435 |                       types
import time:      1234 |       1668 |                     enum
import time:       108 |        108 |                       _sre
import time:       502 |        502 |                         sre_constants
import time:       868 |       1369 |                       sre_parse
import time:       774 |       2250 |                     sre_compile
import time:       315 |        315 |                     _locale
import time:       266 |        266 |                     copyreg
import time:      1187 |       5684 |                   re
import time:       538 |        538 |                   token
import time:      2060 |       8282 |                 tokenize
import time:       995 |      10509 |               linecache
import time:     91646 |     102155 |             traceback
import time:     90384 |      90384 |             warnings
import time:       716 |        716 |               _weakrefset
import time:      1259 |       1975 |             weakref
import time:       162 |        162 |               _string
import time:      2321 |       2482 |             string
import time:      1053 |       1053 |             threading
import time:        99 |         99 |             atexit
import time:      1819 |     200129 |           logging
import time:       955 |     201083 |         concurrent.futures._base
import time:       573 |     201924 |       concurrent.futures
import time:       781 |        781 |         _socket
import time:      2226 |       2226 |           math
import time:      1378 |       1378 |           select
import time:     91586 |      95189 |         selectors
import time:       160 |        160 |         errno
import time:      4047 |     100176 |       socket
import time:      2550 |       2550 |         signal
import time:       713 |        713 |         _posixsubprocess
import time:     92993 |      96255 |       subprocess
import time:      2475 |       2475 |         _ssl
import time:      1010 |       1010 |             _struct
import time:       235 |       1244 |           struct
import time:     85825 |      85825 |           binascii
import time:       631 |      87699 |         base64
import time:      5161 |      95334 |       ssl
import time:      3549 |       3549 |       asyncio.constants
import time:       395 |        395 |               _opcode
import time:       836 |       1231 |             opcode
import time:      1256 |       2486 |           dis
import time:       718 |        718 |             importlib
import time:       632 |       1349 |           importlib.machinery
import time:     95292 |      99126 |         inspect
import time:      2461 |       2461 |           asyncio.format_helpers
import time:      3483 |       5943 |         asyncio.base_futures
import time:     87232 |      87232 |         asyncio.log
import time:      3981 |     196280 |       asyncio.coroutines
import time:       723 |        723 |           _contextvars
import time:      1069 |       1792 |         contextvars
import time:     87770 |      87770 |           asyncio.base_tasks
import time:      2261 |      90031 |         _asyncio
import time:      9031 |     100853 |       asyncio.events
import time:      3099 |       3099 |       asyncio.futures
import time:      1285 |       1285 |       asyncio.protocols
import time:      1635 |       1635 |         asyncio.transports
import time:      3742 |       5377 |       asyncio.sslproto
import time:     94459 |      94459 |       asyncio.tasks
import time:    187970 |    1092612 |     asyncio.base_events
import time:      5250 |       5250 |     asyncio.locks
import time:     88265 |      88265 |     asyncio.runners
import time:      4817 |       4817 |     asyncio.queues
import time:      5412 |       5412 |     asyncio.streams
import time:      2363 |       2363 |     asyncio.subprocess
import time:      3087 |       3087 |       asyncio.base_subprocess
import time:     95452 |      95452 |       asyncio.selector_events
import time:    188089 |     286627 |     asyncio.unix_events
import time:      5128 |    1490471 |   asyncio
import time:       123 |        123 |       gc
import time:       626 |        749 |     uvloop.includes
import time:       559 |        559 |     uvloop._patch
import time:       223 |        223 |       backports_abc
import time:       274 |        274 |       uvloop._noop
import time:       261 |        261 |           _queue
import time:       429 |        689 |         queue
import time:      2178 |       2867 |       concurrent.futures.thread
import time:     94008 |      97371 |     uvloop.loop
import time:      1340 |     100017 |   uvloop
import time:      1220 |       1220 |   fdk.constants
import time:       393 |        393 |   fdk.log
import time:       677 |        677 |           numbers
import time:      1196 |       1873 |         _decimal
import time:       321 |       2193 |       decimal
import time:      1297 |       1297 |         _datetime
import time:      1397 |       2694 |       datetime
import time:       606 |       5492 |     ujson
import time:       407 |        407 |       xml
import time:       690 |       1096 |     xml.etree
import time:       727 |        727 |       contextlib
import time:      2094 |       2094 |       xml.etree.ElementPath
import time:       133 |        133 |               org
import time:        84 |        216 |             org.python
import time:        37 |        253 |           org.python.core
import time:       388 |        640 |         copy
import time:       505 |        505 |         pyexpat
import time:       999 |       2142 |       _elementtree
import time:     90014 |      94976 |     xml.etree.ElementTree
import time:      2823 |       2823 |         iso8601.iso8601
import time:       373 |       3196 |       iso8601
import time:       361 |        361 |         fdk.headers
import time:       565 |        925 |       fdk.context
import time:       646 |        646 |         fdk.response
import time:      1151 |       1796 |       fdk.errors
import time:     92801 |      98717 |     fdk.runner
import time:       687 |        687 |     fdk.http
import time:       389 |        389 |       fdk.http.parser
import time:       319 |        319 |       fdk.http.streams
import time:       318 |        318 |       urllib
import time:      1783 |       1783 |       urllib.parse
import time:       984 |       3791 |     fdk.http.request
import time:      1683 |       1683 |       http
import time:       413 |       2096 |     fdk.http.response
import time:       934 |     207785 |   fdk.http_stream
import time:       906 |    1800790 | fdk

Expected behaviour

cold start shouldn't be a problem to aiohttp

Actual behaviour

cold start within the given constraints is a huge problem to aiohttp

Steps to reproduce

A library that uses aiohttp is in OSS, https://github.com/fnproject/fdk-python.
Feel free to reach out me for more details and code spinnets.

Your environment

Python 3.7.1
Docker (latest)
Linux Alpine, Debian Stretch

[aio-libs-bot]

GitMate.io thinks the contributor most likely able to help you is @asvetlov.

Possibly related issues are #2302 (Issue with MultipartReader), #206 (SSL issue with aiohttp.request), #487 (Issue with mailgun routed data?), #70 (MultiDict issues in http request), and #82 (Fix proxy issue).

[asvetlov]

I have no idea why is you box so slow.
aiohttp import time is 0.2-0.3 sec on my laptop, servers show even better performance.
PYTHONPROFILEIMPORTTIME=1 adds extra slowdown (measurer take CPU time on measuring obviously), with this flag aiohttp import time is increased to 0.3-0.4 sec.

Numbers are 10 times different from yours 4-8 sec.

[denismakogon]

I provided exact constraints for the docker container that are considered to be bare minimum requirements for the UDS servers written with various programming languages to start:
--cpu-quota=10000 --cpu-period=100000 --cpu-shares=128 --memory=128m --kernel-memory=128m --memory-swap=128m. With this constraints aiohttp takes at least 7.5-8 seconds to start and that’s problem that may lead to a statement that aiohttp was never designed for the resources and devices with limited resources.

Your laptop is definitely not the best device to debug this issue, definitely.

[asvetlov]

Have you a concrete proposal for improvement?
Otherwise, let's state that aiohttp (and Python itself also) was not designed to work in a very limited environment and close the issue.

[thehesiod]

@denismakogon I suggest stating what is being imported. I wouldn't import aiohttp, that will get you almost everything, just import what you need.

[denismakogon]

I’m not doing thing like import aiohttp. The only import is: from aiohttp import web - that’s what causes the delay.

[asvetlov]

Looking at numbers from tables above I see that the import of asyncio itself is 2.8 secs from the first table and 1.5 sec from the second.
It doesn't provide any time budget, isn't it?

[denismakogon]

The difference between table one and table two is in a number of imports from the asyncio, that’s why you see the difference.

[denismakogon]

All related routine to an aiohttp is here (master branch): https://github.com/fnproject/fdk-python/blob/master/fdk/http_stream.py#L90-L159

And here's the code that i plan to use as a substitution on aiohttp: https://github.com/fnproject/fdk-python/blob/performance/fdk/http_stream.py#L66-L115

I can provide steps to reproduce including code samples of this lib with dockerfiles, so you can build and see the numbers by yourself.

So, @asvetlov you asked me about the solution here. Well, the best we can do is to actually extract HTTP core API to a library that would be a native asyncio-based http framework which is very similar to SimpleHTTP server (https://docs.python.org/3/library/http.server.html) and make aiohttp be based on it. Like if you need a simple concurrent asyncio HTTP server - use lib, if you'd like to go to production lots of nifty features - go with aiohttp.

[asvetlov]

If you've found a solution that satisfies all your needs -- that's fine.

Closing the issue.

[thehesiod]

interesting that aiohttp.client_reqrep and aiohttp.client seem to be huge. The breakdown seems to be missing a lot of detail.

[lock]

This thread has been automatically locked since there has not been
any recent activity after it was closed. Please open a new issue for
related bugs.

If you feel like there's important points made in this discussion,
please include those exceprts into that new issue.