sieni
/
linux
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
1,397,183 Commits 2 Branches 925 Tags 3.5 GiB
C 97.1%
Assembly 1%
Shell 0.6%
Rust 0.4%
Python 0.4%
Other 0.3%
Go to file
Eric Dumazet aa251c8463 tcp: fix too slow tcp_rcvbuf_grow() action 
While the blamed commits apparently avoided an overshoot,
they also limited how fast a sender can increase BDP at each RTT.

This is not exactly a revert, we do not add the 16 * tp->advmss
cushion we had, and we are keeping the out_of_order_queue
contribution.

Do the same in mptcp_rcvbuf_grow().

Tested:

emulated 50ms rtt (tcp_stream --tcp-tx-delay 50000), cubic 20 second flow.
net.ipv4.tcp_rmem set to "4096 131072 67000000"

perf record -a -e tcp:tcp_rcvbuf_grow sleep 20
perf script

Before:

We can see we fail to roughly double RWIN at each RTT.
Sender is RWIN limited while CWND is ramping up (before getting tcp_wmem
limited).

tcp_stream 33793 [010]  825.717525: tcp:tcp_rcvbuf_grow: time=100869 rtt_us=50428 copied=49152 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=103970 window_clamp=112128 rcv_wnd=106496
tcp_stream 33793 [010]  825.768966: tcp:tcp_rcvbuf_grow: time=51447 rtt_us=50362 copied=86016 inq=0 space=49152 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=107474 window_clamp=112128 rcv_wnd=106496
tcp_stream 33793 [010]  825.821539: tcp:tcp_rcvbuf_grow: time=52577 rtt_us=50243 copied=114688 inq=0 space=86016 ooo=0 scaling_ratio=219 rcvbuf=201096 rcv_ssthresh=167377 window_clamp=172031 rcv_wnd=167936
tcp_stream 33793 [010]  825.871781: tcp:tcp_rcvbuf_grow: time=50248 rtt_us=50237 copied=167936 inq=0 space=114688 ooo=0 scaling_ratio=219 rcvbuf=268129 rcv_ssthresh=224722 window_clamp=229375 rcv_wnd=225280
tcp_stream 33793 [010]  825.922475: tcp:tcp_rcvbuf_grow: time=50698 rtt_us=50183 copied=241664 inq=0 space=167936 ooo=0 scaling_ratio=219 rcvbuf=392617 rcv_ssthresh=331217 window_clamp=335871 rcv_wnd=323584
tcp_stream 33793 [010]  825.973326: tcp:tcp_rcvbuf_grow: time=50855 rtt_us=50213 copied=339968 inq=0 space=241664 ooo=0 scaling_ratio=219 rcvbuf=564986 rcv_ssthresh=478674 window_clamp=483327 rcv_wnd=462848
tcp_stream 33793 [010]  826.023970: tcp:tcp_rcvbuf_grow: time=50647 rtt_us=50248 copied=491520 inq=0 space=339968 ooo=0 scaling_ratio=219 rcvbuf=794811 rcv_ssthresh=671778 window_clamp=679935 rcv_wnd=651264
tcp_stream 33793 [010]  826.074612: tcp:tcp_rcvbuf_grow: time=50648 rtt_us=50227 copied=700416 inq=0 space=491520 ooo=0 scaling_ratio=219 rcvbuf=1149124 rcv_ssthresh=974881 window_clamp=983039 rcv_wnd=942080
tcp_stream 33793 [010]  826.125452: tcp:tcp_rcvbuf_grow: time=50845 rtt_us=50225 copied=987136 inq=8192 space=700416 ooo=0 scaling_ratio=219 rcvbuf=1637502 rcv_ssthresh=1392674 window_clamp=1400831 rcv_wnd=1339392
tcp_stream 33793 [010]  826.175698: tcp:tcp_rcvbuf_grow: time=50250 rtt_us=50198 copied=1347584 inq=0 space=978944 ooo=0 scaling_ratio=219 rcvbuf=2288672 rcv_ssthresh=1949729 window_clamp=1957887 rcv_wnd=1945600
tcp_stream 33793 [010]  826.225947: tcp:tcp_rcvbuf_grow: time=50252 rtt_us=50240 copied=1945600 inq=0 space=1347584 ooo=0 scaling_ratio=219 rcvbuf=3150516 rcv_ssthresh=2687010 window_clamp=2695167 rcv_wnd=2691072
tcp_stream 33793 [010]  826.276175: tcp:tcp_rcvbuf_grow: time=50233 rtt_us=50224 copied=2691072 inq=0 space=1945600 ooo=0 scaling_ratio=219 rcvbuf=4548617 rcv_ssthresh=3883041 window_clamp=3891199 rcv_wnd=3887104
tcp_stream 33793 [010]  826.326403: tcp:tcp_rcvbuf_grow: time=50233 rtt_us=50229 copied=3887104 inq=0 space=2691072 ooo=0 scaling_ratio=219 rcvbuf=6291456 rcv_ssthresh=5370482 window_clamp=5382144 rcv_wnd=5373952
tcp_stream 33793 [010]  826.376723: tcp:tcp_rcvbuf_grow: time=50323 rtt_us=50218 copied=5373952 inq=0 space=3887104 ooo=0 scaling_ratio=219 rcvbuf=9087658 rcv_ssthresh=7755537 window_clamp=7774207 rcv_wnd=7757824
tcp_stream 33793 [010]  826.426991: tcp:tcp_rcvbuf_grow: time=50274 rtt_us=50196 copied=7757824 inq=180224 space=5373952 ooo=0 scaling_ratio=219 rcvbuf=12563759 rcv_ssthresh=10729233 window_clamp=10747903 rcv_wnd=10575872
tcp_stream 33793 [010]  826.477229: tcp:tcp_rcvbuf_grow: time=50241 rtt_us=50078 copied=10731520 inq=180224 space=7577600 ooo=0 scaling_ratio=219 rcvbuf=17715667 rcv_ssthresh=15136529 window_clamp=15155199 rcv_wnd=14983168
tcp_stream 33793 [010]  826.527482: tcp:tcp_rcvbuf_grow: time=50258 rtt_us=50153 copied=15138816 inq=360448 space=10551296 ooo=0 scaling_ratio=219 rcvbuf=24667870 rcv_ssthresh=21073410 window_clamp=21102591 rcv_wnd=20766720
tcp_stream 33793 [010]  826.577712: tcp:tcp_rcvbuf_grow: time=50234 rtt_us=50228 copied=21073920 inq=0 space=14778368 ooo=0 scaling_ratio=219 rcvbuf=34550339 rcv_ssthresh=29517041 window_clamp=29556735 rcv_wnd=29519872
tcp_stream 33793 [010]  826.627982: tcp:tcp_rcvbuf_grow: time=50275 rtt_us=50220 copied=29519872 inq=540672 space=21073920 ooo=0 scaling_ratio=219 rcvbuf=49268707 rcv_ssthresh=42090625 window_clamp=42147839 rcv_wnd=41627648
tcp_stream 33793 [010]  826.678274: tcp:tcp_rcvbuf_grow: time=50296 rtt_us=50185 copied=42053632 inq=761856 space=28979200 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57238168 window_clamp=57316406 rcv_wnd=56606720
tcp_stream 33793 [010]  826.728627: tcp:tcp_rcvbuf_grow: time=50357 rtt_us=50128 copied=43913216 inq=851968 space=41291776 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56524800
tcp_stream 33793 [010]  827.131364: tcp:tcp_rcvbuf_grow: time=50239 rtt_us=50127 copied=43843584 inq=655360 space=43061248 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56696832
tcp_stream 33793 [010]  827.181613: tcp:tcp_rcvbuf_grow: time=50254 rtt_us=50115 copied=43843584 inq=524288 space=43188224 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56807424
tcp_stream 33793 [010]  828.339635: tcp:tcp_rcvbuf_grow: time=50283 rtt_us=50110 copied=43843584 inq=458752 space=43319296 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56864768
tcp_stream 33793 [010]  828.440350: tcp:tcp_rcvbuf_grow: time=50404 rtt_us=50099 copied=43843584 inq=393216 space=43384832 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56922112
tcp_stream 33793 [010]  829.195106: tcp:tcp_rcvbuf_grow: time=50154 rtt_us=50077 copied=43843584 inq=196608 space=43450368 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=57090048

After:

It takes few steps to increase RWIN. Sender is no longer RWIN limited.

tcp_stream 50826 [010]  935.634212: tcp:tcp_rcvbuf_grow: time=100788 rtt_us=50315 copied=49152 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=103970 window_clamp=112128 rcv_wnd=106496
tcp_stream 50826 [010]  935.685642: tcp:tcp_rcvbuf_grow: time=51437 rtt_us=50361 copied=86016 inq=0 space=49152 ooo=0 scaling_ratio=219 rcvbuf=160875 rcv_ssthresh=132969 window_clamp=137623 rcv_wnd=131072
tcp_stream 50826 [010]  935.738299: tcp:tcp_rcvbuf_grow: time=52660 rtt_us=50256 copied=139264 inq=0 space=86016 ooo=0 scaling_ratio=219 rcvbuf=502741 rcv_ssthresh=411497 window_clamp=430079 rcv_wnd=413696
tcp_stream 50826 [010]  935.788544: tcp:tcp_rcvbuf_grow: time=50249 rtt_us=50233 copied=307200 inq=0 space=139264 ooo=0 scaling_ratio=219 rcvbuf=728690 rcv_ssthresh=618717 window_clamp=623371 rcv_wnd=618496
tcp_stream 50826 [010]  935.838796: tcp:tcp_rcvbuf_grow: time=50258 rtt_us=50202 copied=618496 inq=0 space=307200 ooo=0 scaling_ratio=219 rcvbuf=2450338 rcv_ssthresh=1855709 window_clamp=2096187 rcv_wnd=1859584
tcp_stream 50826 [010]  935.889140: tcp:tcp_rcvbuf_grow: time=50347 rtt_us=50166 copied=1261568 inq=0 space=618496 ooo=0 scaling_ratio=219 rcvbuf=4376503 rcv_ssthresh=3725291 window_clamp=3743961 rcv_wnd=3706880
tcp_stream 50826 [010]  935.939435: tcp:tcp_rcvbuf_grow: time=50300 rtt_us=50185 copied=2478080 inq=24576 space=1261568 ooo=0 scaling_ratio=219 rcvbuf=9082648 rcv_ssthresh=7733731 window_clamp=7769921 rcv_wnd=7692288
tcp_stream 50826 [010]  935.989681: tcp:tcp_rcvbuf_grow: time=50251 rtt_us=50221 copied=4915200 inq=114688 space=2453504 ooo=0 scaling_ratio=219 rcvbuf=16574936 rcv_ssthresh=14108110 window_clamp=14179339 rcv_wnd=14024704
tcp_stream 50826 [010]  936.039967: tcp:tcp_rcvbuf_grow: time=50289 rtt_us=50279 copied=9830400 inq=114688 space=4800512 ooo=0 scaling_ratio=219 rcvbuf=32695050 rcv_ssthresh=27896187 window_clamp=27969593 rcv_wnd=27815936
tcp_stream 50826 [010]  936.090172: tcp:tcp_rcvbuf_grow: time=50211 rtt_us=50200 copied=19841024 inq=114688 space=9715712 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57245176 window_clamp=57316406 rcv_wnd=57163776
tcp_stream 50826 [010]  936.140430: tcp:tcp_rcvbuf_grow: time=50262 rtt_us=50197 copied=39501824 inq=114688 space=19726336 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57245176 window_clamp=57316406 rcv_wnd=57163776
tcp_stream 50826 [010]  936.190527: tcp:tcp_rcvbuf_grow: time=50101 rtt_us=50071 copied=43655168 inq=262144 space=39387136 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57032704
tcp_stream 50826 [010]  936.240719: tcp:tcp_rcvbuf_grow: time=50197 rtt_us=50057 copied=43843584 inq=262144 space=43393024 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57032704
tcp_stream 50826 [010]  936.341271: tcp:tcp_rcvbuf_grow: time=50297 rtt_us=50123 copied=43843584 inq=131072 space=43581440 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57147392
tcp_stream 50826 [010]  936.642503: tcp:tcp_rcvbuf_grow: time=50131 rtt_us=50084 copied=43843584 inq=0 space=43712512 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57262080

Fixes: 65c5287892 ("tcp: fix sk_rcvbuf overshoot")
Fixes: e118cdc34d ("mptcp: rcvbuf auto-tuning improvement")
Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/589
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-4-74b43ba4c84c@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 		2025-10-29 17:30:19 -07:00
Documentation dt-bindings: net: sparx5: Narrow properly LAN969x register space windows 2025-10-27 18:23:09 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
arch 17 hotfixes. 12 are cc:stable and 14 are for MM. 2025-10-22 14:57:35 -10:00
block block-6.18-20251016 2025-10-17 08:31:26 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
drivers Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue 2025-10-29 17:23:11 -07:00
fs for-6.18-rc2-tag 2025-10-23 06:44:43 -10:00
include tcp: add newval parameter to tcp_rcvbuf_grow() 2025-10-29 17:30:19 -07:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/rw: check for NULL io_br_sel when putting a buffer 2025-10-15 13:38:53 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel 17 hotfixes. 12 are cc:stable and 14 are for MM. 2025-10-22 14:57:35 -10:00
lib lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt 2025-10-07 13:48:56 -07:00
mm 17 hotfixes. 12 are cc:stable and 14 are for MM. 2025-10-22 14:57:35 -10:00
net tcp: fix too slow tcp_rcvbuf_grow() action 2025-10-29 17:30:19 -07:00
rust rust: bitmap: fix formatting 2025-10-17 13:02:22 +02:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts Kbuild fixes for 6.18 #1 2025-10-11 15:47:12 -07:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ALSA: hda/realtek: Fix mute led for HP Omen 17-cb0xxx 2025-10-17 16:37:21 +02:00
tools tools: ynl: avoid print_field when there is no reply 2025-10-27 18:16:49 -07:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about `clippy::disallowed_macros` configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
…
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap MAINTAINERS: Update Alex Williamson's email address 2025-10-20 15:45:03 -06:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Makefile Linux 6.18-rc2 2025-10-19 15:19:16 -10:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.