Date: Thu, 10 Aug 2023 14:57:38 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 273046] xn0: xen netfront does LRO even if packet forwarding is enabled Message-ID: <bug-273046-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D273046 Bug ID: 273046 Summary: xn0: xen netfront does LRO even if packet forwarding is enabled Product: Base System Version: 13.2-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: dfr@rabson.org On a test VM running on an XCP-NG host, I noticed that large-receive was happening on the VM's interface for traffic that was intended to be routed = to a vnet-enabled jail. The resulting large coalesced packets were too large to = be routed to the jail, causing retransmits and very slow performance inside the vnet jail. In my setup which uses podman to manage setting up network bridging for the vnet jail, net.inet.ip.forwarding is set quite late and after network interfaces are configured so I tried adding net.inet.ip.forwarding=3D1 to sysctl.conf to see if that fixed the problem but the netfront driver was st= ill coalescing segments on receive - this is clearly visible in packet captures= as oversized packets. My impression from reading iflib.c was that LRO should not happen if packet forwarding is enabled but netfront is missing this logic. Based on user reports, this problem may also be present in the virtio vtnet driver - one user reported slow podman network performance for a VM running= on a Proxmox host. --=20 You are receiving this mail because: You are the assignee for the bug.=
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