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From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Rich Lane <rich.lane@bigswitch.com>,
	dev@dpdk.org, Huawei Xie <huawei.xie@intel.com>,
	Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH v2] virtio: use zeroed memory for simple TX header
Date: Tue, 5 Apr 2016 13:34:18 +0800	[thread overview]
Message-ID: <57034E5A.8040402@intel.com> (raw)
In-Reply-To: <20160405042654.GN3080@yliu-dev.sh.intel.com>

Hi,

On 4/5/2016 12:26 PM, Yuanhan Liu wrote:
> On Tue, Apr 05, 2016 at 11:20:05AM +0800, Tan, Jianfeng wrote:
>> Hi,
>>
>> On 4/5/2016 10:11 AM, Rich Lane wrote:
>>> For simple TX the virtio-net header must be zeroed, but it was using memory
>>> that had been initialized with indirect descriptor tables. This resulted in
>>> "unsupported gso type" errors from librte_vhost.
>>>
>>> We can use the same memory for every descriptor to save cachelines in the
>>> vswitch.
>> Pointing all virtio_net_hdr into the same memory may brings performance, but
>> how much? It also introduces difficulty to adding tso in future?
> simple rxtx will not be enabled when TSO is enabled.

Yes, I was missing simple rxtx is conflicting with 
ETH_TXQ_FLAGS_NOOFFLOADS, which indicates that simple rxtx does not want 
to fill any fields in the hdr.
Acked-by: Jianfeng Tan <jianfeng.tan@intel.com>

Thanks,
Jianfeng

>
> 	--yliu

  reply	other threads:[~2016-04-05  5:34 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-05  2:11 [PATCH v2] virtio: use zeroed memory for simple TX header Rich Lane
2016-04-05  3:20 ` Tan, Jianfeng
2016-04-05  4:26   ` Yuanhan Liu
2016-04-05  5:34     ` Tan, Jianfeng [this message]
2016-04-05  4:25 ` Yuanhan Liu
2016-04-06 10:28   ` Thomas Monjalon

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