From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerin Jacob Subject: Re: [PATCH v2 1/3] virtio: conditional compilation cleanup Date: Mon, 4 Jul 2016 18:20:42 +0530 Message-ID: <20160704125041.GA6532@localhost.localdomain> References: <1467028448-8914-1-git-send-email-jerin.jacob@caviumnetworks.com> <1467371814-26754-1-git-send-email-jerin.jacob@caviumnetworks.com> <1467371814-26754-2-git-send-email-jerin.jacob@caviumnetworks.com> <20160704073648.GV2831@yliu-dev.sh.intel.com> <20160704083626.GA12596@localhost.localdomain> <20160704084232.GY2831@yliu-dev.sh.intel.com> <20160704090754.GD12596@localhost.localdomain> <20160704110225.GA2831@yliu-dev.sh.intel.com> <20160704121556.GA5050@localhost.localdomain> <20160704122630.GB26521@yliu-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: , , , , To: Yuanhan Liu Return-path: Received: from NAM02-CY1-obe.outbound.protection.outlook.com (mail-cys01nam02on0062.outbound.protection.outlook.com [104.47.37.62]) by dpdk.org (Postfix) with ESMTP id 2ED472BAD for ; Mon, 4 Jul 2016 14:51:07 +0200 (CEST) Content-Disposition: inline In-Reply-To: <20160704122630.GB26521@yliu-dev.sh.intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Mon, Jul 04, 2016 at 08:26:30PM +0800, Yuanhan Liu wrote: > On Mon, Jul 04, 2016 at 05:45:57PM +0530, Jerin Jacob wrote: > > On Mon, Jul 04, 2016 at 07:02:25PM +0800, Yuanhan Liu wrote: > > > On Mon, Jul 04, 2016 at 02:37:55PM +0530, Jerin Jacob wrote: > > > > On Mon, Jul 04, 2016 at 04:42:32PM +0800, Yuanhan Liu wrote: > > > > > On Mon, Jul 04, 2016 at 02:06:27PM +0530, Jerin Jacob wrote: > > > > > > On Mon, Jul 04, 2016 at 03:36:48PM +0800, Yuanhan Liu wrote: > > > > > > > On Fri, Jul 01, 2016 at 04:46:36PM +0530, Jerin Jacob wrote: > > > > > > > > @@ -494,9 +486,6 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev, > > > > > > > > { > > > > > > > > uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX; > > > > > > > > > > > > > > > > -#ifdef RTE_MACHINE_CPUFLAG_SSSE3 > > > > > > > > - struct virtio_hw *hw = dev->data->dev_private; > > > > > > > > -#endif > > > > > > > > struct virtnet_tx *txvq; > > > > > > > > struct virtqueue *vq; > > > > > > > > uint16_t tx_free_thresh; > > > > > > > > @@ -511,13 +500,14 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev, > > > > > > > > } > > > > > > > > > > > > > > > > #ifdef RTE_MACHINE_CPUFLAG_SSSE3 > > > > > > > > + struct virtio_hw *hw = dev->data->dev_private; > > > > > > > > > > > > > > I'd suggest to move above declaration to ... > > > > > > > > > > > > > > > /* Use simple rx/tx func if single segment and no offloads */ > > > > > > > > if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == VIRTIO_SIMPLE_FLAGS && > > > > > > > > !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) { > > > > > > > > > > > > > > here: we should try to avoid declaring vars in the middle of a code block. > > > > > > > > > > > > Next patch in this series, moving all rxtx handler selection code to > > > > > > separate function(virtio_update_rxtx_handler()) where declaration comes > > > > > > as first line in the function.i.e the comment is taken care of in the > > > > > > series. > > > > > > > > > > Yes, I saw that. But in principle, each patch is atomic: it's not a > > > > > good idea/practice to introduce issues in path A and then fix it in > > > > > path B. > > > > > > > > In my view it was not an issue as I was removing all possible > > > > conditional compilation flag. If I were to move the declaration to top > > > > then another conditional compilation RTE_MACHINE_CPUFLAG_SSSE3 > > > > flag I need to add around declaring the variable. > > > > > > Nope, I was suggesting to move it inside the "if" block. So, this > > > is actually consistent with what you are trying to do. Besides, it > > > removes an declaration in the middle. > > > > Just to get the clarity on "moving inside the 'if' block" > > > > Are you suggesting to have like below? > > > > #ifdef RTE_MACHINE_CPUFLAG_SSSE3 > > + struct virtio_hw *hw; > > /* Use simple rx/tx func if single segment and no offloads */ > > if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == > > VIRTIO_SIMPLE_FLAGS && > > !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) { > > PMD_INIT_LOG(INFO, "Using simple rx/tx path"); > > dev->tx_pkt_burst = virtio_xmit_pkts_simple; > > dev->rx_pkt_burst = virtio_recv_pkts_vec; > > - use_simple_rxtx = 1; > > + hw = dev->data->dev_private; > > + hw->use_simple_rxtx = 1; > > } > > #endif > > > > > > Instead of following scheme in existing patch, > > > > #ifdef RTE_MACHINE_CPUFLAG_SSSE3 > > + struct virtio_hw *hw = dev->data->dev_private; > > /* Use simple rx/tx func if single segment and no offloads */ > > if ((tx_conf->txq_flags & VIRTIO_SIMPLE_FLAGS) == > > VIRTIO_SIMPLE_FLAGS && > > !vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) { > > PMD_INIT_LOG(INFO, "Using simple rx/tx path"); > > dev->tx_pkt_burst = virtio_xmit_pkts_simple; > > dev->rx_pkt_burst = virtio_recv_pkts_vec; > > - use_simple_rxtx = 1; > > + hw->use_simple_rxtx = 1; > > } > > #endif > > > > > > The former case will have issue as "hw" been used in "if" with vtpci_with_feature. > > Oh, my bad. I overlooked it. Sorry for that! > > > OR > > > > if you meant just floating "struct virtio_hw *hw" without RTE_MACHINE_CPUFLAG_SSSE3 > > then it comes error on non x86 as unused "hw" variable. > > > > If you meant something else then let me know? > > I then prefer to keep the "#ifdef .. #endif" on top then. It will stop > us from offending a minor rule, while you can remove the ugly "#ifdef" > block in the next patch. > > Works to you? OK. As you wish :-) > > --yliu