From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12922C76191 for ; Thu, 18 Jul 2019 07:50:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E57AD208C0 for ; Thu, 18 Jul 2019 07:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727544AbfGRHuU (ORCPT ); Thu, 18 Jul 2019 03:50:20 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:41453 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726383AbfGRHuT (ORCPT ); Thu, 18 Jul 2019 03:50:19 -0400 Received: by mail-wr1-f65.google.com with SMTP id c2so24328484wrm.8 for ; Thu, 18 Jul 2019 00:50:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=wKtb4eNPTM8gmdHfl+ucaMw83dCy0zFFLk8YD1DYgwA=; b=Alq++YKPpnq7cQS9h70v9NZ45WqGSvLbg+UgoAq6oZ6l6xgOnqehen9+X8nkQNTTQb UJSSNa5JfqPBpXM7PZDvthT/ODrJLhCeyIym2braDjSwbKeAVod5vb0bGv/ytk9M8yGI WfD2TQK+M9Mc9AeXsBCjzyxMbww9AIqgNRrsVMUaUoQz6IMDPhsJllgoEN2+fxQecBwr Ef/GlNxO5uJA/lU6OPZDtlgqPmBhHk4YhWjV710OoeuBpSTa4jnebfTsWpWvLnIWMuCq Ej1NuOUR2JxTmsaf5K+cOR89qDCGEpqn6LThFHRLDAk4paAvkoCnucSb5IfNDx4v1zXi 4CXg== X-Gm-Message-State: APjAAAVLTHUskZ6kmOLL46+qaig48QaQEyo+lJZ1A26YQzSuRHA1PU+P nVF6vs7b4BetRfYSWkfRIqhAyw== X-Google-Smtp-Source: APXvYqwhtjfQPOZEcza8kvYxdthj0IlRokH67HGXPivPJMSfA2tEdGbKSTgLCbWYotwEWVmgu0HbJw== X-Received: by 2002:adf:cf0d:: with SMTP id o13mr69099wrj.291.1563436218259; Thu, 18 Jul 2019 00:50:18 -0700 (PDT) Received: from steredhat ([5.170.38.133]) by smtp.gmail.com with ESMTPSA id b2sm33517958wrp.72.2019.07.18.00.50.16 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 18 Jul 2019 00:50:17 -0700 (PDT) Date: Thu, 18 Jul 2019 09:50:14 +0200 From: Stefano Garzarella To: "Michael S. Tsirkin" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Hajnoczi , "David S. Miller" , virtualization@lists.linux-foundation.org, Jason Wang , kvm@vger.kernel.org Subject: Re: [PATCH v4 4/5] vhost/vsock: split packets to send using multiple buffers Message-ID: References: <20190717113030.163499-1-sgarzare@redhat.com> <20190717113030.163499-5-sgarzare@redhat.com> <20190717105336-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190717105336-mutt-send-email-mst@kernel.org> User-Agent: NeoMutt/20180716 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jul 17, 2019 at 4:55 PM Michael S. Tsirkin wrote: > > On Wed, Jul 17, 2019 at 01:30:29PM +0200, Stefano Garzarella wrote: > > If the packets to sent to the guest are bigger than the buffer > > available, we can split them, using multiple buffers and fixing > > the length in the packet header. > > This is safe since virtio-vsock supports only stream sockets. > > > > Signed-off-by: Stefano Garzarella > > So how does it work right now? If an app > does sendmsg with a 64K buffer and the other > side publishes 4K buffers - does it just stall? Before this series, the 64K (or bigger) user messages was split in 4K packets (fixed in the code) and queued in an internal list for the TX worker. After this series, we will queue up to 64K packets and then it will be split in the TX worker, depending on the size of the buffers available in the vring. (The idea was to allow EWMA or a configuration of the buffers size, but for now we postponed it) Note: virtio-vsock only supports stream socket for now. Thanks, Stefano