Remove @preconcurrency from internal EventLoopFuture methods

[dnadoba]

Motivation:

We want to remove @preconcurrency from our internal methods and fix the resulting sendable warnings/errors.

Modifications:

• Remove @preconcurrency from internal methods and remove code duplication that is no longer necessary.
• Introduce a new UnsafeMutableTransferBox that can be used to make non-Sendable values Sendable and mutable. It can be used to capture local mutable values in a @Sendable closure and mutate them from within the closure.
• Use UnsafeMutableTransferBox where we currently capture mutable variables from @Sendable closures.

Result:

All internal only uses of @preconcurrency are now gone. Less code duplication.

[dnadoba]

@swift-nio-bot test perf please

[swift-server-bot]

performance report

build id: 141

timestamp: Tue May 31 09:05:08 UTC 2022

results

name	min	max	mean	std
write_http_headers	0.041841595	0.042162621	0.04194412	0.00013921816304714703
http_headers_canonical_form	0.08721896	0.088221045	0.087837235	0.00032144592671275494
http_headers_canonical_form_trimming_whitespace	0.016506351	0.017025838	0.0165691824	0.00016118466766014454
http_headers_canonical_form_trimming_whitespace_from_short_string	0.014996332	0.015050907	0.015011883600000001	1.5254212294022795e-05
http_headers_canonical_form_trimming_whitespace_from_long_string	0.023867765	0.024381373	0.023990360999999998	0.00020605236812788925
bytebuffer_write_12MB_short_string_literals	0.165185929	0.170940291	0.1673064631	0.0018240455372442125
bytebuffer_write_12MB_short_calculated_strings	0.072586224	0.073513558	0.0729645453	0.00035470963337012185
bytebuffer_write_12MB_medium_string_literals	1.009969927	1.012639894	1.0115863307	0.0008578460020171829
bytebuffer_write_12MB_medium_calculated_strings	0.089454901	0.091148415	0.08982014990000001	0.0005020792438491156
bytebuffer_write_12MB_large_calculated_strings	0.1421585	0.143900141	0.142915755	0.0005882406858865057
bytebuffer_lots_of_rw	0.039778213	0.045097278	0.0409538593	0.0019902264817202773
bytebuffer_write_http_response_ascii_only_as_string	0.03276263	0.033701894	0.033196120600000004	0.0003237062987222981
bytebuffer_write_http_response_ascii_only_as_staticstring	0.024131249	0.024681109	0.0242256029	0.0001624382500127696
bytebuffer_write_http_response_some_nonascii_as_string	0.033040439	0.033720065	0.0332121195	0.00023670773360517767
bytebuffer_write_http_response_some_nonascii_as_staticstring	0.023862239	0.024408695	0.0239568226	0.00016183755821206803
no-net_http1_1k_reqs_1_conn	0.010814066	0.011164298	0.0108907586	0.00010329276619202308
http1_1k_reqs_1_conn	0.060365102	0.062175678	0.061271123999999996	0.0006338943397617621
http1_1k_reqs_100_conns	0.089160529	0.090177564	0.0896020712	0.00036621948717698954
future_whenallsucceed_100k_immediately_succeeded_off_loop	0.070763159	0.072420519	0.0713883153	0.0004656737594516023
future_whenallsucceed_100k_immediately_succeeded_on_loop	0.070885267	0.0783877	0.0720905846	0.002236539296062767
future_whenallsucceed_10k_deferred_off_loop	0.029751828	0.031830907	0.0300612523	0.0006297181703923055
future_whenallsucceed_10k_deferred_on_loop	0.012516612	0.013637979	0.012698389	0.0003323244252768001
future_whenallcomplete_100k_immediately_succeeded_off_loop	0.035193679	0.035872026	0.0354733342	0.00022710476204841477
future_whenallcomplete_100k_immediately_succeeded_on_loop	0.03473865	0.03531867	0.0349784679	0.0002309231198691464
future_whenallcomplete_10k_deferred_off_loop	0.022853936	0.023457037	0.0230331932	0.00020561522637295128
future_whenallcomplete_100k_deferred_on_loop	0.069513746	0.072210976	0.0700103197	0.0008180745098920518
future_reduce_10k_futures	0.015592012	0.016128513	0.0157111842	0.00015722638907907438
future_reduce_into_10k_futures	0.013323201	0.013827008	0.0134706576	0.0001428818993210827
channel_pipeline_1m_events	0.09776943	0.098087877	0.0979529851	0.00010505474429653925
websocket_encode_50b_space_at_front_100k_frames_cow	0.044753471	0.04519399	0.044894303600000005	0.00019890514873130424
websocket_encode_50b_space_at_front_1m_frames_cow_masking	0.611042035	0.614919358	0.6117505872	0.0011799416164323805
websocket_encode_1kb_space_at_front_1m_frames_cow	0.469314245	0.469860886	0.46948815890000006	0.00021545395609603662
websocket_encode_50b_no_space_at_front_100k_frames_cow	0.046015042	0.04646243	0.0461525937	0.0002046552681060687
websocket_encode_1kb_no_space_at_front_100k_frames_cow	0.046840418	0.047286808	0.0469376966	0.0001827655102147133
websocket_encode_50b_space_at_front_100k_frames	0.065407365	0.06582775	0.0655502615	0.00018595171671237197
websocket_encode_50b_space_at_front_10k_frames_masking	0.008085133	0.008119663	0.0080951776	1.063024617881536e-05
websocket_encode_1kb_space_at_front_10k_frames	0.012927764	0.013346738	0.0130068941	0.00012318546167687354
websocket_encode_50b_no_space_at_front_100k_frames	0.065581299	0.066216377	0.0657946491	0.00024894414655877696
websocket_encode_1kb_no_space_at_front_10k_frames	0.012242071	0.012333838	0.0122769846	3.026533181784813e-05
websocket_decode_125b_10k_frames	0.01242112	0.012917711	0.0125505172	0.00013913470007378536
websocket_decode_125b_with_a_masking_key_10k_frames	0.012887947	0.013456871	0.013064683099999998	0.0001492514437662907
websocket_decode_64kb_10k_frames	0.012744654	0.012892634	0.0128396439	3.9523078792157905e-05
websocket_decode_64kb_with_a_masking_key_10k_frames	0.013186275	0.01380302	0.0133751272	0.00017454449774057898
websocket_decode_64kb_+1_10k_frames	0.012707507	0.013245631	0.012911679700000001	0.00013355281518231764
websocket_decode_64kb_+1_with_a_masking_key_10k_frames	0.013165012	0.013767081	0.0133817516	0.0001627811310667727
circular_buffer_into_byte_buffer_1kb	0.033015804	0.033461469	0.0330781973	0.0001356366086079927
circular_buffer_into_byte_buffer_1mb	0.064672115	0.065124719	0.0648229379	0.0002008392600577508
byte_buffer_view_iterator_1mb	0.017565411	0.018043702	0.0176293494	0.00014611736861334715
byte_buffer_view_contains_12mb	0.052877288	0.053431932	0.0530487104	0.0002427325973994153
byte_to_message_decoder_decode_many_small	0.040473935	0.041017083	0.040599434000000004	0.000205529901756412
generate_10k_random_request_keys	0.089998361	0.090255506	0.09014280150000001	9.027927254082261e-05
bytebuffer_rw_10_uint32s	0.038552718	0.050471018	0.041463517699999994	0.003260091070866785
bytebuffer_multi_rw_10_uint32s	0.056266382	0.057894415	0.056812978199999996	0.0005653024934471029
lock_1_thread_10M_ops	0.159307072	0.16321952	0.1605934545	0.0013693689066959357
lock_2_threads_10M_ops	0.874296431	0.954113555	0.907574552	0.028111759118031293
lock_4_threads_10M_ops	0.905863823	0.934467087	0.9246733243999999	0.008043961939149693
lock_8_threads_10M_ops	0.938911281	0.978620584	0.9614001876	0.01061209672529046
schedule_100k_tasks	0.073939435	0.112611505	0.081222617	0.012124835351897819
schedule_and_run_100k_tasks	0.413598427	0.433194476	0.4211813642	0.006673638764015786
execute_100k_tasks	0.213184432	0.213502886	0.21328177199999998	8.94189379767445e-05
bytebufferview_copy_to_array_100k_times_1kb	0.011717875	0.011768749	0.0117427906	1.6055858579070366e-05
circularbuffer_copy_to_array_10k_times_1kb	0.02115871	0.021600659	0.0212561133	0.00017688393155654397
deadline_now_1M_times	0.027083897	0.027363673	0.0271659806	7.868037880381092e-05

comparison

name	current	previous	winner	diff
write_http_headers	0.041841595	0.04494874	current	-6%
http_headers_canonical_form	0.08721896	0.08618971	previous	1%
http_headers_canonical_form_trimming_whitespace	0.016506351	0.016404275	previous	0%
http_headers_canonical_form_trimming_whitespace_from_short_string	0.014996332	0.014909545	previous	0%
http_headers_canonical_form_trimming_whitespace_from_long_string	0.023867765	0.023880567	current	0%
bytebuffer_write_12MB_short_string_literals	0.165185929	0.159650229	previous	3%
bytebuffer_write_12MB_short_calculated_strings	0.072586224	0.074616205	current	-2%
bytebuffer_write_12MB_medium_string_literals	1.009969927	0.986515434	previous	2%
bytebuffer_write_12MB_medium_calculated_strings	0.089454901	0.089371476	previous	0%
bytebuffer_write_12MB_large_calculated_strings	0.1421585	0.143660807	current	-1%
bytebuffer_lots_of_rw	0.039778213	0.0438909	current	-9%
bytebuffer_write_http_response_ascii_only_as_string	0.03276263	0.033554623	current	-2%
bytebuffer_write_http_response_ascii_only_as_staticstring	0.024131249	0.025243081	current	-4%
bytebuffer_write_http_response_some_nonascii_as_string	0.033040439	0.032895021	previous	0%
bytebuffer_write_http_response_some_nonascii_as_staticstring	0.023862239	0.02498751	current	-4%
no-net_http1_1k_reqs_1_conn	0.010814066	0.010932114	current	-1%
http1_1k_reqs_1_conn	0.060365102	0.061019775	current	-1%
http1_1k_reqs_100_conns	0.089160529	0.089786101	current	0%
future_whenallsucceed_100k_immediately_succeeded_off_loop	0.070763159	0.079238159	current	-10%
future_whenallsucceed_100k_immediately_succeeded_on_loop	0.070885267	0.079403646	current	-10%
future_whenallsucceed_10k_deferred_off_loop	0.029751828	0.030746471	current	-3%
future_whenallsucceed_10k_deferred_on_loop	0.012516612	0.013532113	current	-7%
future_whenallcomplete_100k_immediately_succeeded_off_loop	0.035193679	0.034848315	previous	0%
future_whenallcomplete_100k_immediately_succeeded_on_loop	0.03473865	0.03482763	current	0%
future_whenallcomplete_10k_deferred_off_loop	0.022853936	0.02280221	previous	0%
future_whenallcomplete_100k_deferred_on_loop	0.069513746	0.069156762	previous	0%
future_reduce_10k_futures	0.015592012	0.016073763	current	-2%
future_reduce_into_10k_futures	0.013323201	0.014186241	current	-6%
channel_pipeline_1m_events	0.09776943	0.097200487	previous	0%
websocket_encode_50b_space_at_front_100k_frames_cow	0.044753471	0.044755096	current	0%
websocket_encode_50b_space_at_front_1m_frames_cow_masking	0.611042035	0.606642781	previous	0%
websocket_encode_1kb_space_at_front_1m_frames_cow	0.469314245	0.469363237	current	0%
websocket_encode_50b_no_space_at_front_100k_frames_cow	0.046015042	0.044705859	previous	2%
websocket_encode_1kb_no_space_at_front_100k_frames_cow	0.046840418	0.047033902	current	0%
websocket_encode_50b_space_at_front_100k_frames	0.065407365	0.064693822	previous	1%
websocket_encode_50b_space_at_front_10k_frames_masking	0.008085133	0.008051824	previous	0%
websocket_encode_1kb_space_at_front_10k_frames	0.012927764	0.012761536	previous	1%
websocket_encode_50b_no_space_at_front_100k_frames	0.065581299	0.064412746	previous	1%
websocket_encode_1kb_no_space_at_front_10k_frames	0.012242071	0.012173678	previous	0%
websocket_decode_125b_10k_frames	0.01242112	0.01266064	current	-1%
websocket_decode_125b_with_a_masking_key_10k_frames	0.012887947	0.012894587	current	0%
websocket_decode_64kb_10k_frames	0.012744654	0.012904563	current	-1%
websocket_decode_64kb_with_a_masking_key_10k_frames	0.013186275	0.013493888	current	-2%
websocket_decode_64kb_+1_10k_frames	0.012707507	0.012973875	current	-2%
websocket_decode_64kb_+1_with_a_masking_key_10k_frames	0.013165012	0.013584908	current	-3%
circular_buffer_into_byte_buffer_1kb	0.033015804	0.033008279	previous	0%
circular_buffer_into_byte_buffer_1mb	0.064672115	0.064673907	current	0%
byte_buffer_view_iterator_1mb	0.017565411	0.017568225	current	0%
byte_buffer_view_contains_12mb	0.052877288	0.052867013	previous	0%
byte_to_message_decoder_decode_many_small	0.040473935	0.040386191	previous	0%
generate_10k_random_request_keys	0.089998361	0.089246848	previous	0%
bytebuffer_rw_10_uint32s	0.038552718	0.037941617	previous	1%
bytebuffer_multi_rw_10_uint32s	0.056266382	0.056369823	current	0%
lock_1_thread_10M_ops	0.159307072	0.159332719	current	0%
lock_2_threads_10M_ops	0.874296431	0.892526582	current	-2%
lock_4_threads_10M_ops	0.905863823	0.844787078	previous	7%
lock_8_threads_10M_ops	0.938911281	0.923208205	previous	1%
schedule_100k_tasks	0.073939435	0.073543081	previous	0%
schedule_and_run_100k_tasks	0.413598427	0.407285025	previous	1%
execute_100k_tasks	0.213184432	0.213286841	current	0%
bytebufferview_copy_to_array_100k_times_1kb	0.011717875	0.010611783	previous	10%
circularbuffer_copy_to_array_10k_times_1kb	0.02115871	0.021147771	previous	0%
deadline_now_1M_times	0.027083897	0.027131436	current	0%

significant differences found

[dnadoba]

@swift-nio-bot test perf please

[swift-server-bot]

performance report

build id: 142

timestamp: Tue May 31 09:10:48 UTC 2022

results

name	min	max	mean	std
write_http_headers	0.041833049	0.042124505	0.041926576	0.00012531055534861283
http_headers_canonical_form	0.088358311	0.08901971	0.0886922703	0.0002543373130121371
http_headers_canonical_form_trimming_whitespace	0.016686863	0.016733653	0.016707091700000003	1.548652366880471e-05
http_headers_canonical_form_trimming_whitespace_from_short_string	0.015192984	0.015714047	0.0152682342	0.0001596619726845155
http_headers_canonical_form_trimming_whitespace_from_long_string	0.024121283	0.024643599	0.024246342400000002	0.00020667278781483426
bytebuffer_write_12MB_short_string_literals	0.165031397	0.170391047	0.1661983837	0.0019499128680484366
bytebuffer_write_12MB_short_calculated_strings	0.072477607	0.073270513	0.07284232090000001	0.00028640782908427175
bytebuffer_write_12MB_medium_string_literals	1.005495327	1.008555135	1.0067830852	0.0009198760129512317
bytebuffer_write_12MB_medium_calculated_strings	0.089464335	0.089987616	0.08964735539999999	0.00019734400369360853
bytebuffer_write_12MB_large_calculated_strings	0.14258249	0.143721218	0.14309133229999998	0.00033882789089514996
bytebuffer_lots_of_rw	0.039778412	0.045357113	0.0406703347	0.0017388240298444391
bytebuffer_write_http_response_ascii_only_as_string	0.032509791	0.033763572	0.0327234337	0.000394598402086095
bytebuffer_write_http_response_ascii_only_as_staticstring	0.024133994	0.024737976	0.024240819599999998	0.00017674006927387246
bytebuffer_write_http_response_some_nonascii_as_string	0.033092038	0.033622712	0.033213468600000004	0.00021382023651251247
bytebuffer_write_http_response_some_nonascii_as_staticstring	0.023866614	0.024489465	0.0239975305	0.0001983868371480598
no-net_http1_1k_reqs_1_conn	0.010866507	0.011056519	0.0109879201	6.757910385688771e-05
http1_1k_reqs_1_conn	0.060134776	0.061432021	0.060856309399999996	0.000493342634893213
http1_1k_reqs_100_conns	0.089282053	0.089881075	0.08950983209999999	0.0001965810448330548
future_whenallsucceed_100k_immediately_succeeded_off_loop	0.070124454	0.071364748	0.0705120364	0.0003797241686897956
future_whenallsucceed_100k_immediately_succeeded_on_loop	0.070289593	0.077662443	0.0713224905	0.0022375178545226424
future_whenallsucceed_10k_deferred_off_loop	0.029688586	0.03021506	0.029834477999999998	0.0001807777934131661
future_whenallsucceed_10k_deferred_on_loop	0.012522119	0.01301808	0.0126327987	0.0001403405668666603
future_whenallcomplete_100k_immediately_succeeded_off_loop	0.034749464	0.036433892	0.0351054921	0.0005188199364160625
future_whenallcomplete_100k_immediately_succeeded_on_loop	0.034534074	0.035258332	0.0347821995	0.0002317706737360361
future_whenallcomplete_10k_deferred_off_loop	0.022891665	0.023424832	0.0230289712	0.00017782898432032956
future_whenallcomplete_100k_deferred_on_loop	0.069099385	0.071460602	0.0696705353	0.0006866139816503793
future_reduce_10k_futures	0.015503449	0.015619738	0.015540420099999999	3.72999660305175e-05
future_reduce_into_10k_futures	0.013251591	0.013733529	0.013334484499999999	0.00014586740189276144
channel_pipeline_1m_events	0.096646785	0.096776634	0.0966971539	4.637475806333899e-05
websocket_encode_50b_space_at_front_100k_frames_cow	0.044767994	0.045200379	0.0448730154	0.0001719689126100027
websocket_encode_50b_space_at_front_1m_frames_cow_masking	0.609506124	0.613053252	0.6101206686999999	0.0011099687856154876
websocket_encode_1kb_space_at_front_1m_frames_cow	0.470600619	0.471177428	0.4708633017	0.0002355248223790453
websocket_encode_50b_no_space_at_front_100k_frames_cow	0.045174396	0.045606467	0.0452683867	0.00017407630541872477
websocket_encode_1kb_no_space_at_front_100k_frames_cow	0.046994859	0.047461877	0.0471064546	0.0001862005731141681
websocket_encode_50b_space_at_front_100k_frames	0.065234665	0.066656362	0.06552837190000001	0.0004456069866454182
websocket_encode_50b_space_at_front_10k_frames_masking	0.008076388	0.008611533	0.0081624743	0.00016480578949650592
websocket_encode_1kb_space_at_front_10k_frames	0.012870209	0.012965401	0.0128990953	3.6572436548885015e-05
websocket_encode_50b_no_space_at_front_100k_frames	0.065146588	0.065621596	0.0653396183	0.00019516153429519967
websocket_encode_1kb_no_space_at_front_10k_frames	0.012228821	0.012657422	0.012281223599999998	0.0001326162096378535
websocket_decode_125b_10k_frames	0.012233282	0.012366945	0.0123047777	3.95150532836679e-05
websocket_decode_125b_with_a_masking_key_10k_frames	0.01281294	0.013276892	0.0129415902	0.00012906996531149737
websocket_decode_64kb_10k_frames	0.012577654	0.01318344	0.0127363164	0.00016959017022038063
websocket_decode_64kb_with_a_masking_key_10k_frames	0.013216508	0.013314903	0.0132595459	3.5720548784045e-05
websocket_decode_64kb_+1_10k_frames	0.012777282	0.013235639	0.012894371600000001	0.0001277286411231075
websocket_decode_64kb_+1_with_a_masking_key_10k_frames	0.0131595	0.01375441	0.013298722199999998	0.00016455270454295183
circular_buffer_into_byte_buffer_1kb	0.033009662	0.033483895	0.0331128863	0.0001846860597157909
circular_buffer_into_byte_buffer_1mb	0.064673169	0.065160918	0.06483072349999999	0.00020480796641854476
byte_buffer_view_iterator_1mb	0.01756998	0.018063249	0.017630277399999998	0.00015255523210023158
byte_buffer_view_contains_12mb	0.052891197	0.053355064	0.052997531	0.00018715560117838932
byte_to_message_decoder_decode_many_small	0.04066174	0.04121646	0.0407856267	0.00021164063945915091
generate_10k_random_request_keys	0.089407779	0.089714635	0.0895282598	9.834151027109571e-05
bytebuffer_rw_10_uint32s	0.038725979	0.050847383	0.04161273	0.0033593561782622717
bytebuffer_multi_rw_10_uint32s	0.056287957	0.058063068	0.0568715744	0.0005525491810923468
lock_1_thread_10M_ops	0.159346478	0.164067004	0.1602103379	0.0014316474621507743
lock_2_threads_10M_ops	0.883900059	0.930883552	0.8990645519999999	0.017269769918649872
lock_4_threads_10M_ops	1.019644556	1.05938278	1.0471553483	0.011571727730963544
lock_8_threads_10M_ops	0.851770537	0.890177785	0.8768528513	0.011189518094133752
schedule_100k_tasks	0.073459561	0.112253651	0.0810968369	0.012165123735545236
schedule_and_run_100k_tasks	0.413425018	0.430777234	0.4246161752	0.005727545795190063
execute_100k_tasks	0.213427933	0.214849888	0.2141128531	0.0004715686096414966
bytebufferview_copy_to_array_100k_times_1kb	0.011027687	0.011102502	0.0110634859	2.1721332210269623e-05
circularbuffer_copy_to_array_10k_times_1kb	0.021161644	0.021613506	0.0212601387	0.00018216613954913103
deadline_now_1M_times	0.027101207	0.027455766	0.0271621043	0.00010517630580870704

comparison

name	current	previous	winner	diff
write_http_headers	0.041833049	0.04494874	current	-6%
http_headers_canonical_form	0.088358311	0.08618971	previous	2%
http_headers_canonical_form_trimming_whitespace	0.016686863	0.016404275	previous	1%
http_headers_canonical_form_trimming_whitespace_from_short_string	0.015192984	0.014909545	previous	1%
http_headers_canonical_form_trimming_whitespace_from_long_string	0.024121283	0.023880567	previous	1%
bytebuffer_write_12MB_short_string_literals	0.165031397	0.159650229	previous	3%
bytebuffer_write_12MB_short_calculated_strings	0.072477607	0.074616205	current	-2%
bytebuffer_write_12MB_medium_string_literals	1.005495327	0.986515434	previous	1%
bytebuffer_write_12MB_medium_calculated_strings	0.089464335	0.089371476	previous	0%
bytebuffer_write_12MB_large_calculated_strings	0.14258249	0.143660807	current	0%
bytebuffer_lots_of_rw	0.039778412	0.0438909	current	-9%
bytebuffer_write_http_response_ascii_only_as_string	0.032509791	0.033554623	current	-3%
bytebuffer_write_http_response_ascii_only_as_staticstring	0.024133994	0.025243081	current	-4%
bytebuffer_write_http_response_some_nonascii_as_string	0.033092038	0.032895021	previous	0%
bytebuffer_write_http_response_some_nonascii_as_staticstring	0.023866614	0.02498751	current	-4%
no-net_http1_1k_reqs_1_conn	0.010866507	0.010932114	current	0%
http1_1k_reqs_1_conn	0.060134776	0.061019775	current	-1%
http1_1k_reqs_100_conns	0.089282053	0.089786101	current	0%
future_whenallsucceed_100k_immediately_succeeded_off_loop	0.070124454	0.079238159	current	-11%
future_whenallsucceed_100k_immediately_succeeded_on_loop	0.070289593	0.079403646	current	-11%
future_whenallsucceed_10k_deferred_off_loop	0.029688586	0.030746471	current	-3%
future_whenallsucceed_10k_deferred_on_loop	0.012522119	0.013532113	current	-7%
future_whenallcomplete_100k_immediately_succeeded_off_loop	0.034749464	0.034848315	current	0%
future_whenallcomplete_100k_immediately_succeeded_on_loop	0.034534074	0.03482763	current	0%
future_whenallcomplete_10k_deferred_off_loop	0.022891665	0.02280221	previous	0%
future_whenallcomplete_100k_deferred_on_loop	0.069099385	0.069156762	current	0%
future_reduce_10k_futures	0.015503449	0.016073763	current	-3%
future_reduce_into_10k_futures	0.013251591	0.014186241	current	-6%
channel_pipeline_1m_events	0.096646785	0.097200487	current	0%
websocket_encode_50b_space_at_front_100k_frames_cow	0.044767994	0.044755096	previous	0%
websocket_encode_50b_space_at_front_1m_frames_cow_masking	0.609506124	0.606642781	previous	0%
websocket_encode_1kb_space_at_front_1m_frames_cow	0.470600619	0.469363237	previous	0%
websocket_encode_50b_no_space_at_front_100k_frames_cow	0.045174396	0.044705859	previous	1%
websocket_encode_1kb_no_space_at_front_100k_frames_cow	0.046994859	0.047033902	current	0%
websocket_encode_50b_space_at_front_100k_frames	0.065234665	0.064693822	previous	0%
websocket_encode_50b_space_at_front_10k_frames_masking	0.008076388	0.008051824	previous	0%
websocket_encode_1kb_space_at_front_10k_frames	0.012870209	0.012761536	previous	0%
websocket_encode_50b_no_space_at_front_100k_frames	0.065146588	0.064412746	previous	1%
websocket_encode_1kb_no_space_at_front_10k_frames	0.012228821	0.012173678	previous	0%
websocket_decode_125b_10k_frames	0.012233282	0.01266064	current	-3%
websocket_decode_125b_with_a_masking_key_10k_frames	0.01281294	0.012894587	current	0%
websocket_decode_64kb_10k_frames	0.012577654	0.012904563	current	-2%
websocket_decode_64kb_with_a_masking_key_10k_frames	0.013216508	0.013493888	current	-2%
websocket_decode_64kb_+1_10k_frames	0.012777282	0.012973875	current	-1%
websocket_decode_64kb_+1_with_a_masking_key_10k_frames	0.0131595	0.013584908	current	-3%
circular_buffer_into_byte_buffer_1kb	0.033009662	0.033008279	previous	0%
circular_buffer_into_byte_buffer_1mb	0.064673169	0.064673907	current	0%
byte_buffer_view_iterator_1mb	0.01756998	0.017568225	previous	0%
byte_buffer_view_contains_12mb	0.052891197	0.052867013	previous	0%
byte_to_message_decoder_decode_many_small	0.04066174	0.040386191	previous	0%
generate_10k_random_request_keys	0.089407779	0.089246848	previous	0%
bytebuffer_rw_10_uint32s	0.038725979	0.037941617	previous	2%
bytebuffer_multi_rw_10_uint32s	0.056287957	0.056369823	current	0%
lock_1_thread_10M_ops	0.159346478	0.159332719	previous	0%
lock_2_threads_10M_ops	0.883900059	0.892526582	current	0%
lock_4_threads_10M_ops	1.019644556	0.844787078	previous	20%
lock_8_threads_10M_ops	0.851770537	0.923208205	current	-7%
schedule_100k_tasks	0.073459561	0.073543081	current	0%
schedule_and_run_100k_tasks	0.413425018	0.407285025	previous	1%
execute_100k_tasks	0.213427933	0.213286841	previous	0%
bytebufferview_copy_to_array_100k_times_1kb	0.011027687	0.010611783	previous	3%
circularbuffer_copy_to_array_10k_times_1kb	0.021161644	0.021147771	previous	0%
deadline_now_1M_times	0.027101207	0.027131436	current	0%

significant differences found

[Lukasa]

Nice, LGTM.

[dnadoba]

If we remove @preconcurency from EventLoopFuture._whenComplete we have a memory regression in our test_1000_udpconnections.swift allocation test of 1 allocation per iteration. I have added @preconcurency for this method again with a TODO and reported the issue here: swiftlang/swift#59249
We can still decided later if we accept this regression or not and remove @preconcurency in a separate PR.