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From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Cc: dev@dpdk.org, thomas.monjalon@6wind.com,
	bruce.richardson@intel.com, jianbo.liu@linaro.org,
	huawei.xie@intel.com
Subject: Re: [dpdk-dev] [PATCH v2 1/3] virtio: conditional compilation cleanup
Date: Mon, 4 Jul 2016 20:26:30 +0800	[thread overview]
Message-ID: <20160704122630.GB26521@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <20160704121556.GA5050@localhost.localdomain>

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?

	--yliu

  reply	other threads:[~2016-07-04 12:25 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-27 11:54 [dpdk-dev] [PATCH 0/4] Virtio NEON support for ARM Jerin Jacob
2016-06-27 11:54 ` [dpdk-dev] [PATCH 1/4] virtio: Fix compile time dependency of use_simple_rxtx usage Jerin Jacob
2016-06-27 11:54 ` [dpdk-dev] [PATCH 2/4] virtio: introduce RTE_LIBRTE_VIRTIO_INC_VECTOR Jerin Jacob
2016-06-27 14:19   ` Thomas Monjalon
2016-06-27 14:48     ` Jerin Jacob
2016-06-27 14:59       ` Thomas Monjalon
2016-06-29 11:18         ` Jerin Jacob
2016-06-29 11:25           ` Thomas Monjalon
2016-06-29 11:40             ` Jerin Jacob
2016-06-30  5:44               ` Yuanhan Liu
2016-06-27 11:54 ` [dpdk-dev] [PATCH 3/4] virtio: move SSE based Rx implementation to separate file Jerin Jacob
2016-06-28  6:17   ` Jianbo Liu
2016-06-29 11:27     ` Jerin Jacob
2016-06-30  5:43       ` Yuanhan Liu
2016-06-27 11:54 ` [dpdk-dev] [PATCH 4/4] virtio: add neon support Jerin Jacob
2016-07-01 11:16 ` [dpdk-dev] From: Jerin Jacob <jerin.jacob@caviumnetworks.com> Jerin Jacob
2016-07-01 11:16   ` [dpdk-dev] [PATCH v2 1/3] virtio: conditional compilation cleanup Jerin Jacob
2016-07-04  7:36     ` Yuanhan Liu
2016-07-04  8:36       ` Jerin Jacob
2016-07-04  8:42         ` Yuanhan Liu
2016-07-04  9:07           ` Jerin Jacob
2016-07-04 11:02             ` Yuanhan Liu
2016-07-04 12:15               ` Jerin Jacob
2016-07-04 12:26                 ` Yuanhan Liu [this message]
2016-07-04 12:50                   ` Jerin Jacob
2016-07-04 12:57                     ` Yuanhan Liu
2016-07-01 11:16   ` [dpdk-dev] [PATCH v2 2/3] virtio: move SSE based Rx implementation to separate file Jerin Jacob
2016-07-04  7:42     ` Yuanhan Liu
2016-07-04  8:38       ` Jerin Jacob
2016-07-01 11:16   ` [dpdk-dev] [PATCH v2 3/3] virtio: add neon support Jerin Jacob
2016-07-04  7:53     ` Yuanhan Liu
2016-07-04  8:55       ` Jerin Jacob
2016-07-04  9:02         ` Yuanhan Liu
2016-07-05 12:49   ` [dpdk-dev] [PATCH v3 0/4] Virtio NEON support for ARM Jerin Jacob
2016-07-05 12:49     ` [dpdk-dev] [PATCH v3 1/4] virtio: conditional compilation cleanup Jerin Jacob
2016-07-05 12:49     ` [dpdk-dev] [PATCH v3 2/4] virtio: move SSE based Rx implementation to separate file Jerin Jacob
2016-08-18  6:52       ` Yuanhan Liu
2016-08-19  3:24         ` Jerin Jacob
2016-08-23  7:43           ` Yuanhan Liu
2016-07-05 12:49     ` [dpdk-dev] [PATCH v3 3/4] virtio: add cpuflag based vector handler selection Jerin Jacob
2016-07-05 12:49     ` [dpdk-dev] [PATCH v3 4/4] virtio: add neon support Jerin Jacob
2016-07-06  3:11       ` Jianbo Liu
2016-09-28  0:37     ` [dpdk-dev] [PATCH v3 0/4] Virtio NEON support for ARM Yuanhan Liu
2016-07-01 11:19 ` [dpdk-dev] [PATCH v2 0/3] " Jerin Jacob

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