From: "Wang, Haiyue" <haiyue.wang@intel.com>
To: "Morten Brørup" <mb@smartsharesystems.com>,
"Guo, Jia" <jia.guo@intel.com>,
"Yang, Qiming" <qiming.yang@intel.com>,
"Xing, Beilei" <beilei.xing@intel.com>,
"Zhao1, Wei" <wei.zhao1@intel.com>,
"Zhang, Qi Z" <qi.z.zhang@intel.com>,
"Wu, Jingjing" <jingjing.wu@intel.com>
Cc: "Richardson, Bruce" <bruce.richardson@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Zhang, Helin" <helin.zhang@intel.com>,
"Yigit, Ferruh" <ferruh.yigit@intel.com>,
"barbette@kth.se" <barbette@kth.se>
Subject: Re: [dpdk-dev] [PATCH v2 0/5] maximize vector rx burst for PMDs
Date: Fri, 28 Aug 2020 02:06:07 +0000 [thread overview]
Message-ID: <BN8PR11MB37953723252F126F73207B6AF7520@BN8PR11MB3795.namprd11.prod.outlook.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35C6125C@smartserver.smartshare.dk>
> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Morten Brørup
> Sent: Thursday, August 27, 2020 20:38
> To: Guo, Jia <jia.guo@intel.com>; Yang, Qiming <qiming.yang@intel.com>; Xing, Beilei
> <beilei.xing@intel.com>; Zhao1, Wei <wei.zhao1@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>; Wu,
> Jingjing <jingjing.wu@intel.com>
> Cc: Richardson, Bruce <bruce.richardson@intel.com>; dev@dpdk.org; Zhang, Helin <helin.zhang@intel.com>;
> Yigit, Ferruh <ferruh.yigit@intel.com>; barbette@kth.se
> Subject: Re: [dpdk-dev] [PATCH v2 0/5] maximize vector rx burst for PMDs
>
> > From: Jeff Guo [mailto:jia.guo@intel.com]
> > Sent: Thursday, August 27, 2020 12:10 PM
> >
> > The limitation of burst size in vector rx was removed, since it should
> > retrieve as much received packets as possible. And also the scattered
> > receive path should use a wrapper function to achieve the goal of
> > burst maximizing.
> >
> > This patch set aims to maximize vector rx burst for for
> > ixgbe/i40e/ice/iavf/fm10k PMDs.
> >
> > v2->v1:
> > 1:add fm10k driver case
> > 2:refine some doc
> >
>
> I now noticed that the vector functions also does:
> nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_I40E_DESCS_PER_LOOP);
>
> I am not sure about this, but if I read it correctly, calling rte_eth_rx_burst() with nb_pkts = 33
> (not 32) would only return 32 packets, even if more packets are available. (I assume that
> RTE_I40E_DESCS_PER_LOOP is 32.) In this case, I guess that you need to read the remaining of the
> requested packets using the non-vector function in order to support any nb_pkts value.
>
This is vector instruction handling design requirement, like for avx2: #define ICE_DESCS_PER_LOOP_AVX 8,
if deep into the real loop handling, you will get the point why doing RTE_ALIGN_FLOOR. ;-)
_ice_recv_raw_pkts_vec_avx2:
for (i = 0, received = 0; i < nb_pkts; i += ICE_DESCS_PER_LOOP_AVX, rxdp += ICE_DESCS_PER_LOOP_AVX)
Maybe it is worth to tell PMD to stop using vector by calling rte_eth_rx_queue_setup with the application
burst size it wants.
> That is, unless the rte_eth_rx_burst() API is extended with requirements to nb_pkts, as discussed in
> the other thread:
> http://inbox.dpdk.org/dev/20200827114117.GD569@bricha3-
> MOBL.ger.corp.intel.com/T/#mc8051e9022d6aeb20c51c5a226b2274d3d6d4266
>
>
> Med venlig hilsen / kind regards
> - Morten Brørup
>
>
next prev parent reply other threads:[~2020-08-28 2:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 10:10 Jeff Guo
2020-08-27 10:10 ` [dpdk-dev] [PATCH v2 1/5] net/ixgbe: maximize vector rx burst for ixgbe Jeff Guo
2020-08-27 10:10 ` [dpdk-dev] [PATCH v2 2/5] net/i40e: maximize vector rx burst for i40e Jeff Guo
2020-08-27 10:10 ` [dpdk-dev] [PATCH v2 3/5] net/ice: maximize vector rx burst for ice Jeff Guo
2020-08-31 4:41 ` Zhang, Qi Z
2020-08-31 5:24 ` Jeff Guo
2020-08-27 10:10 ` [dpdk-dev] [PATCH v2 4/5] net/iavf: maximize vector rx burst for iavf Jeff Guo
2020-08-27 10:10 ` [dpdk-dev] [PATCH v2 5/5] net/fm10k: maximize vector rx burst for fm10k Jeff Guo
2020-08-27 12:38 ` [dpdk-dev] [PATCH v2 0/5] maximize vector rx burst for PMDs Morten Brørup
2020-08-28 2:06 ` Wang, Haiyue [this message]
2020-08-28 6:39 ` Jeff Guo
2020-08-28 11:45 ` Morten Brørup
2020-08-28 20:30 ` Stephen Hemminger
2020-08-31 14:27 ` Wang, Haiyue
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