Public bug reported: Recently a patch has been accepted on the Linux Kernel regarding the TCP stack which fix an additional +40ms latency on ARM64 CPU architecture without impacting other CPU types.
More information can be find in here: https://lore.kernel.org/netdev/20240119190133.43698-1-dipi...@amazon.com/ Would be possible to include the following patch as part of Linux image on the most recent and LTS maintained Ubuntu versions? Patch: ``` --- net/ipv4/tcp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index ff6838ca2e58..7bce79beca2b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -722,6 +722,7 @@ void tcp_push(struct sock *sk, int flags, int mss_now, if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags); + smp_mb__after_atomic(); } /* It is possible TX completion already happened * before we set TSQ_THROTTLED. -- ``` ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2051727 Title: tcp: Add memory barrier to tcp_push() Status in linux package in Ubuntu: New Bug description: Recently a patch has been accepted on the Linux Kernel regarding the TCP stack which fix an additional +40ms latency on ARM64 CPU architecture without impacting other CPU types. More information can be find in here: https://lore.kernel.org/netdev/20240119190133.43698-1-dipi...@amazon.com/ Would be possible to include the following patch as part of Linux image on the most recent and LTS maintained Ubuntu versions? Patch: ``` --- net/ipv4/tcp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index ff6838ca2e58..7bce79beca2b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -722,6 +722,7 @@ void tcp_push(struct sock *sk, int flags, int mss_now, if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING); set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags); + smp_mb__after_atomic(); } /* It is possible TX completion already happened * before we set TSQ_THROTTLED. -- ``` To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2051727/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
