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From: Stephen Hemminger <stephen@networkplumber.org>
To: "Xie, Huawei" <huawei.xie@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [PATCH v2 0/5] virtio: Tx performance improvements
Date: Tue, 27 Oct 2015 08:52:12 +0900	[thread overview]
Message-ID: <20151027085212.24ce7e5e@samsung9> (raw)
In-Reply-To: <C37D651A908B024F974696C65296B57B4B13AC87@SHSMSX101.ccr.corp.intel.com>

On Fri, 23 Oct 2015 09:00:38 +0000
"Xie, Huawei" <huawei.xie@intel.com> wrote:

> >> Why use merge-able rx header here in the tx region?  
> > If mergeable rx is negotiated then the header must be used for
> > both Tx and Rx. I chose to allocate the largest possible header
> > needed, rather than having to deal with variable size data structure.  
> Our original code is also using merge-able header for TX descriptor if
> this negotiated.
> I checked the virtio spec, all of the merge-able header is about
> receiving buffers, which is expected. That is why i feel weird here.
> Maybe not a big deal?

Since num_buffers is only in merge-able header, the negotiation is implied
to be symmetric.


Reading 0.95 spec 

Under "Packet Transmission"
 3. If the driver negotatied the VIRTIO_NET_F_MGR_RXBUF feature
    the num_buffers field is set to zero.

  reply	other threads:[~2015-10-26 23:52 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-19  5:16 [PATCH v2 0/5] virtio: Tx performance improvements Stephen Hemminger
2015-10-19  5:16 ` [PATCH 1/5] virtio: clean up space checks on xmit Stephen Hemminger
2015-10-19  8:02   ` Xie, Huawei
2015-10-19 15:48     ` Stephen Hemminger
2015-10-19 16:27       ` Xie, Huawei
2015-10-19  5:16 ` [PATCH 2/5] virtio: don't use unlikely for normal tx stuff Stephen Hemminger
2015-10-19  5:16 ` [PATCH 3/5] virtio: use indirect ring elements Stephen Hemminger
2015-10-19 13:19   ` Xie, Huawei
2015-10-19 15:47     ` Stephen Hemminger
2015-10-19 16:18       ` Xie, Huawei
2015-10-30 18:01   ` Thomas Monjalon
2015-10-19  5:16 ` [PATCH 4/5] virtio: use any layout on transmit Stephen Hemminger
2015-10-19 16:28   ` Xie, Huawei
2015-10-19 16:43     ` Stephen Hemminger
2015-10-19 16:56       ` Xie, Huawei
2015-10-26 23:47         ` Stephen Hemminger
2015-10-19 17:19     ` Stephen Hemminger
2015-10-19  5:16 ` [PATCH 5/5] virtio: optimize transmit enqueue Stephen Hemminger
2015-10-20  1:48   ` Xie, Huawei
2015-10-21 13:18 ` [PATCH v2 0/5] virtio: Tx performance improvements Thomas Monjalon
2015-10-22 10:38   ` Xie, Huawei
2015-10-22 12:13     ` Xie, Huawei
2015-10-22 16:04     ` Stephen Hemminger
2015-10-23  9:00       ` Xie, Huawei
2015-10-26 23:52         ` Stephen Hemminger [this message]
2015-10-27  1:56           ` Xie, Huawei
2015-10-27  2:23             ` Stephen Hemminger
2015-10-27  2:38               ` Xie, Huawei
2015-10-26 14:05 ` Xie, Huawei
2016-01-05  8:10   ` Xie, Huawei
2016-01-06 12:03     ` Thomas Monjalon
2016-01-14 13:49       ` Xie, Huawei
2016-03-04  6:18         ` Xie, Huawei
2016-03-04 18:17           ` Stephen Hemminger
2016-03-08  1:38             ` Xie, Huawei

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