From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTP id 6EF505A005E for ; Tue, 13 Dec 2022 23:48:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670971732; 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=8qI6rJ6+U29jDWSmuqYfj1iILjgQxtawdWpQghTLzQ0=; b=CnhLp+RqXzmBBP2e3FK4Xhkwn9s6/nF3Q7oeyc2X89LCozAdjkS67Ir4mj4Xog14qlbN83 yjfVeFCoF8wU0ArJj2owc6YY0HQkFzEQq1wU/9IE32QfQDDAuilBIwycPOdY/hFfChnsoR 7DIswxbwfkwbsk1IbH2YOfJFcjA8Da8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-612-jf8SI241N1i4z8An8d_YdQ-1; Tue, 13 Dec 2022 17:48:51 -0500 X-MC-Unique: jf8SI241N1i4z8An8d_YdQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B4A0681DA1D; Tue, 13 Dec 2022 22:48:50 +0000 (UTC) Received: from maya.cloud.tilaa.com (ovpn-208-4.brq.redhat.com [10.40.208.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3C4D52166B29; Tue, 13 Dec 2022 22:48:50 +0000 (UTC) Date: Tue, 13 Dec 2022 23:48:47 +0100 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH 4/8] udp: Receive multiple datagrams at once on the pasta sock->tap path Message-ID: <20221213234847.6c723ad9@elisabeth> In-Reply-To: <20221205081425.2614425-5-david@gibson.dropbear.id.au> References: <20221205081425.2614425-1-david@gibson.dropbear.id.au> <20221205081425.2614425-5-david@gibson.dropbear.id.au> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: 3JXZUEUHEKYEGO4JPN2WWVLKKBJHO4TM X-Message-ID-Hash: 3JXZUEUHEKYEGO4JPN2WWVLKKBJHO4TM X-MailFrom: sbrivio@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top X-Mailman-Version: 3.3.3 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Sorry for the long delay here, On Mon, 5 Dec 2022 19:14:21 +1100 David Gibson wrote: > Usually udp_sock_handler() will receive and forward multiple (up to 32) > datagrams in udp_sock_handler(), then forward them all to the tap > interface. For unclear reasons, though, when in pasta mode we will only > receive and forward a single datagram at a time. Change it to receive > multiple datagrams at once, like the other paths. This is explained in the commit message of 6c931118643c ("tcp, udp: Receive batching doesn't pay off when writing single frames to tap"). I think it's worth re-checking the throughput now as this path is a bit different, but unfortunately I didn't include this in the "perf" tests :( because at the time I introduced those I wasn't sure it even made sense to have traffic from the same host being directed to the tap device. The iperf3 runs were I observed this are actually the ones from the Podman demo. Ideally that case should be also checked in the perf/pasta_udp tests. How fundamental is this for the rest of the series? I couldn't find any actual dependency on this but I might be missing something. -- Stefano