From nobody Tue Sep 23 20:08:59 2025 X-Original-To: bugs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cWWJq5Bqtz67sDf for ; Tue, 23 Sep 2025 20:08:59 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cWWJq4KHYz3YYQ for ; Tue, 23 Sep 2025 20:08:59 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758658139; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=y2VUSLcHnP04Rme4SAtfiOQ2UPmX0x80rXl2/4sGslk=; b=IFdHD2iYPdGQ8kBDDd6XrvzwLwuAHxZVYTD0u4L5R/9Pels4oR3wTH8RU+MdiE+OMfw8a8 6KHcTjZdsSh1UwP+EeOD5wrLTERw9Mwr7v1QDtZfTCzhPPp8x4Q+PiDAocnrO+WsKtdiba 89mjDvBLdJ1aiMj+mKBrBNRYHVhdNfUxm8NklvZiDFBl/PT7YUUSuQzex+L/95LW4LaiRw SSdHv1tpNci1mxgo/EzZZ5CbC+fBmOmfjhCvD9o9a+ptAJbXayocW9OjgUpq91+jp0eT1K fR3i8fyyF/dXfr3nBXvx9sQx2Vj4qYDc6Pol6SwRbVpzyRfiXrGzJT1mo3wIlw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758658139; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=y2VUSLcHnP04Rme4SAtfiOQ2UPmX0x80rXl2/4sGslk=; b=VVz9dLn1WTIfXTk4sPMTvTB3LZLbi1fAcsXxyxjAhPx4o+2He2dGEjgvxvExXCHheJJ51a cYEIYNVHcLgL/+wYJyInXkzb+NAX6DA+2oBY/udQbG5AsiE+hogl6cGZdqgNFBks+Sese0 e8GC37sgAvJ6R+YUG9rY28sXnNtSNtS6FXzR1H5i/5rOjsDJPtZjUk7VfJOp+B9kdrIX+a 3qVNYk64syfR52prswZlMsJ26C30jIyedQVAbEj0hYSJY53zRTi4j3UbD920sE5zaXUZS9 O97dA5Sz49tjuU5cl153V8ySnlwJPXUhBvkHCUnaKcnD40b2qyDpxQf3w7dcNA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1758658139; a=rsa-sha256; cv=none; b=RwYvLhUhFzmlRvZrm3IQeNlePENIjlBs58qvWi2l4Ee3DL5vZR1pNQHv8AisjPErsF3gPo kDn+RtSIUOsBg7Fbb7MKmQGW8eVhHPD2F7aJJAHAamKhzGtM89WQDODdSnWcLSMWPHi9AC f5SHD2pCU2UBH7hQigIGGefGIvGFG3LIvvw/ggoH7P2eThr2+a2yAuNneHf5Rqv1QyKANW e+bzmneS0y4MAUeyo1cOU3JOStzKs3y//24VyeCsKjb94igaEQAOUQn9k3c9B78HkheHOU a8LwU+uEFpLF3MhDUE74rIe0gygPkgYokCzVqZk19RNZ6YBQzJCaNrDb4mrN3Q== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4cWWJq3TWmz10h8 for ; Tue, 23 Sep 2025 20:08:59 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 58NK8x4R019711 for ; Tue, 23 Sep 2025 20:08:59 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 58NK8xGg019710 for bugs@FreeBSD.org; Tue, 23 Sep 2025 20:08:59 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 263229] virtio vtnet driver with rxcsum errors Date: Tue, 23 Sep 2025 20:08:59 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 13.1-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: tuexen@freebsd.org X-Bugzilla-Status: In Progress X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@FreeBSD.org MIME-Version: 1.0 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D263229 --- Comment #34 from Michael Tuexen --- (In reply to mike from comment #30) OK, I now understand what was going on: * When you have enabled hardware LRO on the vtnet driver, you forward too l= arge packets. They trigger an ICMP response (packet too big), which is ignored, because the sender is honoring already the MTU. * The sender is doing TSO, which is generating the too large packets. Howev= er, not all packets where actually TSOed. This is fixed in: https://cgit.FreeBSD.org/src/commit/?id=3D1bb72d3d6eee50232b6d6acbc201f9aaa= c93e2b5 Now the throughput will be even less in your problematic scenario. * The crucial point is that hardware LRO should be turned off by default, a= nd software LRO should be turned on by default. This does not interfere with IP forwarding. This is something also done by other NIC drivers supporting hardware and software LRO. The patch is under review D52684. With that you setup works just fine in the default setup (as it should). * Finally there is some cleanup to actually announce receive checksum offloading for IPv6 in review D52682. Once that is reviewed and committed, I will close this PR. --=20 You are receiving this mail because: You are the assignee for the bug.=