From: "Xie, Huawei" <huawei.xie@intel.com>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>,
"Huawei@dpdk.org" <Huawei@dpdk.org>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] virtio: fix virtio_net_hdr desc pointing to the same buffer
Date: Mon, 14 Dec 2015 01:21:45 +0000 [thread overview]
Message-ID: <C37D651A908B024F974696C65296B57B4BB92519@SHSMSX103.ccr.corp.intel.com> (raw)
In-Reply-To: <ED26CBA2FAD1BF48A8719AEF02201E36671D59@SHSMSX103.ccr.corp.intel.com>
On 12/12/2015 3:39 PM, Tan, Jianfeng wrote:
>
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Huawei@dpdk.org
>> Sent: Friday, December 11, 2015 12:08 AM
>> To: dev@dpdk.org
>> Subject: [dpdk-dev] [PATCH] virtio: fix virtio_net_hdr desc pointing to the
>> same buffer
>>
>> The virtio_net_hdr desc all pointed to the same buffer. It doesn't cause
>> issue because in the simple TX mode we don't use the header. This patch
>> makes the header desc point to different buffer.
>>
>> Signed-off-by: Huawei Xie <huawei.xie@intel.com>
>> ---
>> drivers/net/virtio/virtio_rxtx.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
>> index 74b39ef..6cfd315 100644
>> --- a/drivers/net/virtio/virtio_rxtx.c
>> +++ b/drivers/net/virtio/virtio_rxtx.c
>> @@ -352,7 +352,7 @@ virtio_dev_vring_start(struct virtqueue *vq, int
>> queue_type)
>> vq->vq_ring.desc[i + mid_idx].next = i;
>> vq->vq_ring.desc[i + mid_idx].addr =
>> vq->virtio_net_hdr_mem +
>> - mid_idx * vq->hw-
>>> vtnet_hdr_size;
>> + i * vq->hw->vtnet_hdr_size;
>> vq->vq_ring.desc[i + mid_idx].len =
>> vq->hw->vtnet_hdr_size;
>> vq->vq_ring.desc[i + mid_idx].flags =
>> --
>> 1.8.1.4
> So in the case when header is not used, shall the way of pointing to all header bufs to one buf
> help improve the performance? At least, it saves some of cache lines.
If we don't touch the virtio_net buffer, it doesn't help performance
pointing to same buffer.
>
> Thanks,
> Jianfeng
>
next prev parent reply other threads:[~2015-12-14 1:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-10 16:07 Huawei
2015-12-12 7:39 ` Tan, Jianfeng
2015-12-14 1:21 ` Xie, Huawei [this message]
2015-12-14 1:35 ` Tan, Jianfeng
2015-12-14 3:01 ` Yuanhan Liu
2015-12-14 9:32 ` Thomas Monjalon
2015-12-14 11:47 ` Yuanhan Liu
2015-12-14 12:44 ` Thomas Monjalon
2015-12-14 13:09 ` Yuanhan Liu
2015-12-14 13:38 ` Xie, Huawei
2015-12-14 13:45 ` Thomas Monjalon
2015-12-14 13:58 ` Xie, Huawei
2016-02-10 15:36 ` Bruce Richardson
2015-12-10 17:57 [dpdk-dev] [PATCH 0/4] vhost: Fix various coverity issues in vhost library Huawei
2015-12-10 17:57 ` [dpdk-dev] [PATCH] virtio: fix virtio_net_hdr desc pointing to the same buffer Huawei
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