This bug was fixed in the package linux-aws - 5.4.0-1037.39
---------------
linux-aws (5.4.0-1037.39) focal; urgency=medium
* focal/linux-aws: 5.4.0-1037.39 -proposed tracker (LP: #1911314)
* aws: network performance regression due to initial TCP receive buffer size
change (LP: #1910200)
- tcp: select sane initial rcvq_space.space for big MSS
* Disable Atari partition support for linux-aws (LP: #1908264)
- [Config] Disable Atari partition support
* aws: xen-netfront: prevent potential error on hibernate (LP: #1906850)
- SAUCE: xen-netfront: prevent unnecessary close on hibernate
[ Ubuntu: 5.4.0-63.71 ]
* focal/linux: 5.4.0-63.71 -proposed tracker (LP: #1911333)
* overlay: permission regression in 5.4.0-51.56 due to patches related to
CVE-2020-16120 (LP: #1900141)
- ovl: do not fail because of O_NOATIME
* Focal update: v5.4.79 upstream stable release (LP: #1907151)
- net/mlx5: Use async EQ setup cleanup helpers for multiple EQs
- net/mlx5: poll cmd EQ in case of command timeout
- net/mlx5: Fix a race when moving command interface to events mode
- net/mlx5: Add retry mechanism to the command entry index allocation
* Kernel 5.4.0-56 Wi-Fi does not connect (LP: #1906770)
- mt76: fix fix ampdu locking
* [Ubuntu 21.04 FEAT] mpt3sas: Request to include the patch set which supports
topology where zoning is enabled in expander (LP: #1899802)
- scsi: mpt3sas: Define hba_port structure
- scsi: mpt3sas: Allocate memory for hba_port objects
- scsi: mpt3sas: Rearrange _scsih_mark_responding_sas_device()
- scsi: mpt3sas: Update hba_port's sas_address & phy_mask
- scsi: mpt3sas: Get device objects using sas_address & portID
- scsi: mpt3sas: Rename transport_del_phy_from_an_existing_port()
- scsi: mpt3sas: Get sas_device objects using device's rphy
- scsi: mpt3sas: Update hba_port objects after host reset
- scsi: mpt3sas: Set valid PhysicalPort in SMPPassThrough
- scsi: mpt3sas: Handling HBA vSES device
- scsi: mpt3sas: Add bypass_dirty_port_flag parameter
- scsi: mpt3sas: Handle vSES vphy object during HBA reset
- scsi: mpt3sas: Add module parameter multipath_on_hba
- scsi: mpt3sas: Bump driver version to 35.101.00.00
[ Ubuntu: 5.4.0-62.70 ]
* focal/linux: 5.4.0-62.70 -proposed tracker (LP: #1911144)
* CVE-2020-28374
- SAUCE: target: fix XCOPY NAA identifier lookup
* Packaging resync (LP: #1786013)
- update dkms package versions
-- Kelsey Skunberg <kelsey.skunb...@canonical.com> Wed, 13 Jan 2021
19:01:10 -0700
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux-aws in Ubuntu.
https://bugs.launchpad.net/bugs/1910200
Title:
aws: network performance regression due to initial TCP receive buffer
size change
Status in linux-aws package in Ubuntu:
New
Status in linux-aws source package in Bionic:
Fix Released
Status in linux-aws source package in Focal:
Fix Released
Status in linux-aws source package in Groovy:
Fix Committed
Bug description:
[Impact]
AWS has seen some customers reporting networking performance
degradation after they upgraded their Ubuntu instanceses. This
regression is highly impacting customers who are using MTU=9000 (which
is the default in EC2).
[Test case]
Bug reproduced internally in AWS (no test case provided), but
apparently it is very easy to reproduce simply by measuring networking
performance.
[Fix]
AWS worked internally and found that the regression has been
introduced by:
a337531b942b ("tcp: up initial rmem to 128KB and SYN rwin to around
64KB")
To solve the problem we need to apply the following upstream commit
that explicitly fixes the problem introduced by the commit above:
33ae7b5bb841 ("tcp: select sane initial rcvq_space.space for big
MSS")
[Regression potential]
Upstream fix that is only affecting the initial TCP buffer space and
allows the TCP window size to be dynamically increased, basically
restoring the previous (correct) behavior, so regression potential is
minimal.
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