From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6C4E92153EA for ; Wed, 29 Oct 2025 08:20:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761726005; cv=none; b=cYzFFEjjJn1i1HcY4wq0A1tkp8ArpNZ5PtrkRY9Gk6tLCAwrlILKluYDZg3MLmn+tXuxpkhZjtKj/MQe/sXE9OhLE+wNJwrT/U+pEQGAv3fxPAiGKR9O5ma8aO+u36fZaXaQaLZ32qVWjkb5rT92N6aGu7Tjzc6JlXQ3BMMVk3M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761726005; c=relaxed/simple; bh=dF3Bio0TgnJ38n1yJDNKl2Un84TNaqbPbXxpnnYQNmY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RQs593GM/CjIgkAwJiIhjA2mdZxJAq59dbyidURBoOEfbAbkT2KPJyxAMQcc+SvDkb0RgMSEheEuJNFNS5nEWfVy+zrcGHUZMU9PZR32WlqsR88pWzOYkSb6VJ/mazP8tm1W2eqe1TjM2a6r7nzWxirpQB7r24dzmWQdJCKOZdQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=bbpPYvcj; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bbpPYvcj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1761726002; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jlHEB3885pfS5dzEnYONWhgNpmOARZh1obJdxfgK8IE=; b=bbpPYvcjCJmE3PLd+21MfD5M7J1pQZPlUttyOk9YAbe8sZlxshvOgBHc+6AhU4isEOFKT6 DurP8pi8qYK4YPBN5i3h6Eo+OymCslatmOSCL2B9wksdcwnKhwe8PfmEGRZ9OzCk8qyA4j U/VCaHJ9iEVlJjAiAx5ooE4sqnDr8fM= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-661-DhFUI0sPNOqARAlxVfrQxA-1; Wed, 29 Oct 2025 04:20:00 -0400 X-MC-Unique: DhFUI0sPNOqARAlxVfrQxA-1 X-Mimecast-MFC-AGG-ID: DhFUI0sPNOqARAlxVfrQxA_1761726000 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-470fd92ad57so82330225e9.3 for ; Wed, 29 Oct 2025 01:20:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761726000; x=1762330800; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=jlHEB3885pfS5dzEnYONWhgNpmOARZh1obJdxfgK8IE=; b=wZw8tLN0Og+jETaOaUVvo6tSc94edOTjOu35FuC6IyxDZ8Z+0wMpbgBOuYqjvgw+OU cVSzToGmIwSVYs+wy/JeM7EJQB7Cfg+M7OngqFktiYaRYBPhECsae8VFGkeu8Lv1FIj+ svoqjPHKS3aJR1vg6KQNzlnqd8y+9rq1oCAG9RyhJDexQ2dzoN79sxIvGsv7Kad1vRlQ KYMe9qbBQAynyZUsWboDjqz86Lyz2c8Oe8eeZ23Jiy97C9Ydt7EnmvqnuYF2rYviIXDB AVmB5uEiyQVirx+ilhKSSzoSRQLIYPcYBgJ1bnluYoeU1qAL9M+6QwNF9JoG5Mrc30+e K6XQ== X-Forwarded-Encrypted: i=1; AJvYcCUUlBVY2c/6iPY5xDWY/m515UeSVy6tCRcr0+P6/qtumbWJoqm1piaKzcqdVb/cG7g5l6XznMtwUvzJh1M=@vger.kernel.org X-Gm-Message-State: AOJu0Yyn+dPOAApmM8ploLrna06T7HZH8+9iCFbAqr6BpD2xXnkkw3JI YRfqkBty3IonDffk7GsIRSIHSJhIWPUQ4QMBGfDzR6aeH2C6whVAHJJxw0sp3r6Ug6C+9Ja3sPp YIROeQup1tnzNceb0+dEssC+H4I9t1/4ZTadIbZN3XEvXJcRTDpDVHi83dGFJ6KRXvQ== X-Gm-Gg: ASbGncsCzVizGDDSmQqVJnqQRFf9rofdqbtNyaAhavjqGyDJY9jtWMRYKIOgG4j70PZ e2B1SupGk+3t2PdkLiKp33VXJVjxqlJ6UzyfLK0vHbFVXFl7a2C3ChSxSb+Dgk5W4tlLaKx+tpJ frTIX0BqxIPMcguK/CC4a9F4EUbjK3GVCvp1CgYVpPqX0G/7EdSB1JD5CZK7aPfV4P2LyExrrvk 5tYANUIgnkmFdk11n6lUwyIL8Q9tmTeRF+Sa/BVU33pjlJCpU98u3jIjzHg0oT3Botxc6bwssDy VZxK88CajPjgwdJcbT/3bR6AfMfG3kgIWdlYmgkOowMYIByZ5nRqfCbTwil8BaxNKCMcJxPu/yK vhn0qaYNtpQwoUY9x1x1o/ezOJ59UAflN9y7L9yaUw+PohOw= X-Received: by 2002:a05:600c:3f0d:b0:468:86e0:de40 with SMTP id 5b1f17b1804b1-4771e32f67amr17216415e9.4.1761725999690; Wed, 29 Oct 2025 01:19:59 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFIKqhZC0CRaoe+oh+5iFeCWKZfBRUDuYDM2nN5t0zCHgNGsk8VxrCIMd1bsBbPfplLJXnHhw== X-Received: by 2002:a05:600c:3f0d:b0:468:86e0:de40 with SMTP id 5b1f17b1804b1-4771e32f67amr17216155e9.4.1761725999244; Wed, 29 Oct 2025 01:19:59 -0700 (PDT) Received: from ?IPV6:2a0d:3344:2712:7e10:4d59:d956:544f:d65c? ([2a0d:3344:2712:7e10:4d59:d956:544f:d65c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4771e3937b3sm33177645e9.5.2025.10.29.01.19.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Oct 2025 01:19:58 -0700 (PDT) Message-ID: Date: Wed, 29 Oct 2025 09:19:57 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] virtio_net: fix alignment for virtio_net_hdr_v1_hash To: Jason Wang , mst@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org Cc: virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20251029012434.75576-1-jasowang@redhat.com> Content-Language: en-US From: Paolo Abeni In-Reply-To: <20251029012434.75576-1-jasowang@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/29/25 2:24 AM, Jason Wang wrote: > From: "Michael S. Tsirkin" > > Changing alignment of header would mean it's no longer safe to cast a > 2 byte aligned pointer between formats. Use two 16 bit fields to make > it 2 byte aligned as previously. > > This fixes the performance regression since > commit ("virtio_net: enable gso over UDP tunnel support.") as it uses > virtio_net_hdr_v1_hash_tunnel which embeds > virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net > shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps. > > Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.") > Cc: stable@vger.kernel.org > Signed-off-by: Michael S. Tsirkin > Signed-off-by: Jason Wang Whoops, I replied to the older thread before reading this one. Acked-by: Paolo Abeni