From: "Xie, Huawei" <huawei.xie@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v2 0/5] virtio: Tx performance improvements
Date: Tue, 27 Oct 2015 02:38:24 +0000 [thread overview]
Message-ID: <C37D651A908B024F974696C65296B57B4B144E40@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <CAOaVG15O59cJc7ktFczr5cLCeNLo2zY5Md-ab56ZA3Q2RP6v9w@mail.gmail.com>
On 10/27/2015 10:23 AM, Stephen Hemminger wrote:
> You need to use the extended mergeable rx buffer format.
> It is a virtio spec requirement, look at Linux virtio network driver
> or ask the virtio maintainers for Linux
> if you need more clarification.
Yes, it is spec requirement as far as we know though num_buffers might
not be used.
So far not a big deal for us. Let us get clarification from mst later.
>
> On Tue, Oct 27, 2015 at 10:56 AM, Xie, Huawei <huawei.xie@intel.com
> <mailto:huawei.xie@intel.com>> wrote:
>
> On 10/27/2015 7:52 AM, Stephen Hemminger wrote:
> > On Fri, 23 Oct 2015 09:00:38 +0000
> > "Xie, Huawei" <huawei.xie@intel.com
> <mailto: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.
> >
> Can we come to the conclusion that in tx case, we use merge-able
> header
> though number_buffers is not used at all?
> > 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.
> >
> >
>
>
next prev parent reply other threads:[~2015-10-27 2:38 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-19 5:16 Stephen Hemminger
2015-10-19 5:16 ` [dpdk-dev] [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 ` [dpdk-dev] [PATCH 2/5] virtio: don't use unlikely for normal tx stuff Stephen Hemminger
2015-10-19 5:16 ` [dpdk-dev] [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 ` [dpdk-dev] [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 ` [dpdk-dev] [PATCH 5/5] virtio: optimize transmit enqueue Stephen Hemminger
2015-10-20 1:48 ` Xie, Huawei
2015-10-21 13:18 ` [dpdk-dev] [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
2015-10-27 1:56 ` Xie, Huawei
2015-10-27 2:23 ` Stephen Hemminger
2015-10-27 2:38 ` Xie, Huawei [this message]
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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