From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ananyev, Konstantin" Subject: Re: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support Date: Fri, 15 Sep 2017 08:15:53 +0000 Message-ID: <2601191342CEEE43887BDE71AB9772584F24B2D9@irsmsx105.ger.corp.intel.com> References: <1504598270-60080-1-git-send-email-jiayu.hu@intel.com> <1505184211-36728-1-git-send-email-jiayu.hu@intel.com> <1505184211-36728-3-git-send-email-jiayu.hu@intel.com> <2601191342CEEE43887BDE71AB9772584F249FE8@irsmsx105.ger.corp.intel.com> <20170913104407.GA57844@dpdk15.sh.intel.com> <2601191342CEEE43887BDE71AB9772584F24AACB@irsmsx105.ger.corp.intel.com> <20170914060705.GA60858@dpdk15.sh.intel.com> <2601191342CEEE43887BDE71AB9772584F24ADD2@irsmsx105.ger.corp.intel.com> <2601191342CEEE43887BDE71AB9772584F24AE4D@irsmsx105.ger.corp.intel.com> <2601191342CEEE43887BDE71AB9772584F24B081@irsmsx105.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "dev@dpdk.org" , "Tan, Jianfeng" To: "Hu, Jiayu" , "Kavanagh, Mark B" Return-path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 4567B2BBE for ; Fri, 15 Sep 2017 10:15:56 +0200 (CEST) In-Reply-To: Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi Jiayu, > -----Original Message----- > From: Hu, Jiayu > Sent: Friday, September 15, 2017 8:55 AM > To: Ananyev, Konstantin ; Kavanagh, Mark B = > Cc: dev@dpdk.org; Tan, Jianfeng > Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support >=20 > Hi Konstantin, >=20 > > -----Original Message----- > > From: Ananyev, Konstantin > > Sent: Friday, September 15, 2017 2:39 AM > > To: Kavanagh, Mark B ; Hu, Jiayu > > > > Cc: dev@dpdk.org; Tan, Jianfeng > > Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > > > > > > > -----Original Message----- > > > From: Kavanagh, Mark B > > > Sent: Thursday, September 14, 2017 4:42 PM > > > To: Hu, Jiayu ; Ananyev, Konstantin > > > > > Cc: dev@dpdk.org; Tan, Jianfeng > > > Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > > > > >From: Hu, Jiayu > > > >Sent: Thursday, September 14, 2017 11:01 AM > > > >To: Ananyev, Konstantin ; Kavanagh, > > Mark B > > > > > > > >Cc: dev@dpdk.org; Tan, Jianfeng > > > >Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > > > > > >Hi Konstantin and Mark, > > > > > > > >> -----Original Message----- > > > >> From: Ananyev, Konstantin > > > >> Sent: Thursday, September 14, 2017 5:36 PM > > > >> To: Hu, Jiayu > > > >> Cc: dev@dpdk.org; Kavanagh, Mark B ; > > Tan, > > > >> Jianfeng > > > >> Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > >> > > > >> > > > >> > > > >> > -----Original Message----- > > > >> > From: Hu, Jiayu > > > >> > Sent: Thursday, September 14, 2017 10:29 AM > > > >> > To: Ananyev, Konstantin > > > >> > Cc: dev@dpdk.org; Kavanagh, Mark B ; > > Tan, > > > >> Jianfeng > > > >> > Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > >> > > > > >> > Hi Konstantin, > > > >> > > > > >> > > -----Original Message----- > > > >> > > From: Ananyev, Konstantin > > > >> > > Sent: Thursday, September 14, 2017 4:47 PM > > > >> > > To: Hu, Jiayu > > > >> > > Cc: dev@dpdk.org; Kavanagh, Mark B > > ; > > > >> Tan, > > > >> > > Jianfeng > > > >> > > Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > >> > > > > > >> > > Hi Jiayu, > > > >> > > > > > >> > > > -----Original Message----- > > > >> > > > From: Hu, Jiayu > > > >> > > > Sent: Thursday, September 14, 2017 7:07 AM > > > >> > > > To: Ananyev, Konstantin > > > >> > > > Cc: dev@dpdk.org; Kavanagh, Mark B > > ; > > > >> Tan, > > > >> > > Jianfeng > > > >> > > > Subject: Re: [PATCH v3 2/5] gso: add TCP/IPv4 GSO support > > > >> > > > > > > >> > > > Hi Konstantin, > > > >> > > > > > > >> > > > On Thu, Sep 14, 2017 at 06:10:37AM +0800, Ananyev, Konstanti= n > > wrote: > > > >> > > > > > > > >> > > > > Hi Jiayu, > > > >> > > > > > > > >> > > > > > > > > > >> > > > > > > > > > >> > > > > > > > -----Original Message----- > > > >> > > > > > > > From: Ananyev, Konstantin > > > >> > > > > > > > Sent: Tuesday, September 12, 2017 12:18 PM > > > >> > > > > > > > To: Hu, Jiayu ; dev@dpdk.org > > > >> > > > > > > > Cc: Kavanagh, Mark B ; Ta= n, > > > >> Jianfeng > > > >> > > > > > >> > > > > > > > Subject: RE: [PATCH v3 2/5] gso: add TCP/IPv4 GSO su= pport > > > >> > > > > > > > > > > >> > > > > > > > > result, when all of its GSOed segments are freed, = the > > packet > > > >is > > > >> > > freed > > > >> > > > > > > > > automatically. > > > >> > > > > > > > > diff --git a/lib/librte_gso/rte_gso.c > > > >b/lib/librte_gso/rte_gso.c > > > >> > > > > > > > > index dda50ee..95f6ea6 100644 > > > >> > > > > > > > > --- a/lib/librte_gso/rte_gso.c > > > >> > > > > > > > > +++ b/lib/librte_gso/rte_gso.c > > > >> > > > > > > > > @@ -33,18 +33,53 @@ > > > >> > > > > > > > > > > > >> > > > > > > > > #include > > > >> > > > > > > > > > > > >> > > > > > > > > +#include > > > >> > > > > > > > > + > > > >> > > > > > > > > #include "rte_gso.h" > > > >> > > > > > > > > +#include "gso_common.h" > > > >> > > > > > > > > +#include "gso_tcp4.h" > > > >> > > > > > > > > > > > >> > > > > > > > > int > > > >> > > > > > > > > rte_gso_segment(struct rte_mbuf *pkt, > > > >> > > > > > > > > - struct rte_gso_ctx gso_ctx __rte_unused, > > > >> > > > > > > > > + struct rte_gso_ctx gso_ctx, > > > >> > > > > > > > > struct rte_mbuf **pkts_out, > > > >> > > > > > > > > uint16_t nb_pkts_out) > > > >> > > > > > > > > { > > > >> > > > > > > > > + struct rte_mempool *direct_pool, *indirect_pool; > > > >> > > > > > > > > + struct rte_mbuf *pkt_seg; > > > >> > > > > > > > > + uint16_t gso_size; > > > >> > > > > > > > > + uint8_t ipid_delta; > > > >> > > > > > > > > + int ret =3D 1; > > > >> > > > > > > > > + > > > >> > > > > > > > > if (pkt =3D=3D NULL || pkts_out =3D=3D NULL || n= b_pkts_out > > < 1) > > > >> > > > > > > > > return -EINVAL; > > > >> > > > > > > > > > > > >> > > > > > > > > - pkts_out[0] =3D pkt; > > > >> > > > > > > > > + if (gso_ctx.gso_size >=3D pkt->pkt_len || > > > >> > > > > > > > > + (pkt->packet_type & > > gso_ctx.gso_types) !=3D > > > >> > > > > > > > > + pkt->packet_type) { > > > >> > > > > > > > > + pkts_out[0] =3D pkt; > > > >> > > > > > > > > + return ret; > > > >> > > > > > > > > + } > > > >> > > > > > > > > + > > > >> > > > > > > > > + direct_pool =3D gso_ctx.direct_pool; > > > >> > > > > > > > > + indirect_pool =3D gso_ctx.indirect_pool; > > > >> > > > > > > > > + gso_size =3D gso_ctx.gso_size; > > > >> > > > > > > > > + ipid_delta =3D gso_ctx.ipid_flag =3D=3D > > RTE_GSO_IPID_INCREASE; > > > >> > > > > > > > > + > > > >> > > > > > > > > + if (is_ipv4_tcp(pkt->packet_type)) { > > > >> > > > > > > > > > > >> > > > > > > > Probably we need here: > > > >> > > > > > > > If (is_ipv4_tcp(pkt->packet_type) && (gso_ctx->gso_= types > > & > > > >> > > DEV_TX_OFFLOAD_TCP_TSO) !=3D 0) {... > > > >> > > > > > > > > > >> > > > > > > Sorry, actually it probably should be: > > > >> > > > > > > If (pkt->ol_flags & (PKT_TX_TCP_SEG | PKT_TX_IPV4) =3D= =3D > > > >> PKT_TX_IPV4 > > > >> > > && > > > >> > > > > > > (gso_ctx->gso_types & DEV_TX_OFFLOAD_TCP_TSO) != =3D 0) > > {... > > > >> > > > > > > > > >> > > > > > I don't quite understand why the GSO library should be a= ware if > > > >the > > > >> TSO > > > >> > > > > > flag is set or not. Applications can query device TSO ca= pability > > > >> before > > > >> > > > > > they call the GSO library. Do I misundertsand anything? > > > >> > > > > > > > > >> > > > > > Additionally, we don't need to check if the packet is a = TCP/IPv4 > > > >> packet > > > >> > > here? > > > >> > > > > > > > >> > > > > Well, right now PMD we doesn't rely on ptype to figure ou= t what > > > >type > > > >> of > > > >> > > packet and > > > >> > > > > what TX offload have to be performed. > > > >> > > > > Instead it looks at TX part of ol_flags, and > > > >> > > > > My thought was that as what we doing is actually TSO in SW= , it > > would > > > >> be > > > >> > > good > > > >> > > > > to use the same API here too. > > > >> > > > > Also with that approach, by setting ol_flags properly user= can use > > > >the > > > >> > > same gso_ctx and still > > > >> > > > > specify what segmentation to perform on a per-packet basis= . > > > >> > > > > > > > >> > > > > Alternative way is to rely on ptype to distinguish should > > > >segmentation > > > >> be > > > >> > > performed on that package or not. > > > >> > > > > The only advantage I see here is that if someone would lik= e to > > add > > > >> GSO > > > >> > > for some new protocol, > > > >> > > > > he wouldn't need to introduce new TX flag value for > > mbuf.ol_flags. > > > >> > > > > Though he still would need to update TX_OFFLOAD_* capabili= ties > > and > > > >> > > probably packet_type definitions. > > > >> > > > > > > > >> > > > > So from my perspective first variant (use HW TSO API) is m= ore > > > >> plausible. > > > >> > > > > Wonder what is your and Mark opinions here? > > > >> > > > > > > >> > > > In the first choice, you mean: > > > >> > > > the GSO library uses gso_ctx->gso_types and mbuf->ol_flags t= o call > > a > > > >> > > specific GSO > > > >> > > > segmentation function (e.g. gso_tcp4_segment(), gso_tunnel_x= xx()) > > for > > > >> > > each input packet. > > > >> > > > Applications should parse the packet type, and set an exactl= y > > correct > > > >> > > DEV_TX_OFFLOAD_*_TSO > > > >> > > > flag to gso_types and ol_flags according to the packet type.= That is, > > > >the > > > >> > > value of gso_types > > > >> > > > is on a per-packet basis. Using gso_ctx->gso_types and mbuf- > > >ol_flags > > > >> at > > > >> > > the same time > > > >> > > > is because that DEV_TX_OFFLOAD_*_TSO only tells tunnelling t= ype > > and > > > >> the > > > >> > > inner L4 type, and > > > >> > > > we need to know L3 type by ol_flags. With this design, HW > > > >> segmentation > > > >> > > and SW segmentation > > > >> > > > are indeed consistent. > > > >> > > > > > > >> > > > If I understand it correctly, applications need to set 'ol_f= lags =3D > > > >> > > PKT_TX_IPV4' and > > > >> > > > 'gso_types =3D DEV_TX_OFFLOAD_VXLAN_TNL_TSO' for a > > > >> > > "ether+ipv4+udp+vxlan+ether+ipv4+ > > > >> > > > tcp+payload" packet. But PKT_TX_IPV4 just present the inner = L3 > > type > > > >for > > > >> > > tunneled packet. > > > >> > > > How about the outer L3 type? Always assume the inner and the > > outer L3 > > > >> > > type are the same? > > > >> > > > > > >> > > It think that for that case you'll have to set in ol_flags: > > > >> > > > > > >> > > PKT_TX_IPV4 | PKT_TX_OUTER_IPV4 | PKT_TX_TUNNEL_VXLAN | > > > >> > > PKT_TX_TCP_SEG > > > >> > > > > >> > OK, so it means PKT_TX_TCP_SEG is also used for tunneled TSO. Th= e > > > >> > GSO library doesn't need gso_types anymore. > > > >> > > > >> You still might need gso_ctx.gso_types to let user limit what type= s of > > > >> segmentation > > > >> that particular gso_ctx supports. > > > >> An alternative would be to assume that each gso_ctx supports all > > > >> currently implemented segmentations. > > > >> This is possible too, but probably not very convenient to the user= . > > > > > > > >Hmm, make sense. > > > > > > > >One thing to confirm: the value of gso_types should be > > DEV_TX_OFFLOAD_*_TSO, > > > >or new macros? > > > > > > Hi Jiayu, Konstantin, > > > > > > I think that the existing macros are fine, as they provide a consiste= nt view > > of segmentation capabilities to the application/user. > > > > +1 > > I also think it is better to re-use DEV_TX_OFFLOAD_*_TSO. >=20 > There might be an 'issue', if we use 'PKT_TX_TCP_SEG' to tell the > GSO library to segment a packet or not. Given the scenario that > an application only wants to do GSO and doesn't want to use TSO. > The application sets 'mbuf->ol_flags=3DPKT_TX_TCP_SEG' and doesn't > set mbuf->tso_segsz. Then the GSO library segments the packet, and > all output GSO segments have the same ol_flags as the input packet > (in current GSO library design). Then the output GSO segments are > transmitted to rte_eth_tx_prepare(). If the NIC is i40e, its TX prepare f= unction, > i40e_prep_pkts, checks if mbuf->tso_segsz is in the range of I40E_MIN_TSO= _MSS > and I40E_MAX_TSO_MSS, when PKT_TX_TCP_SEG is set. So an error happens in > this scenario, since tso_segsz is 0. >=20 > In fact, it may confuse the PMD driver when set PKT_TX_TCP_SEG but don't = want > to do TSO. One solution is that the GSO library removes the PKT_TX_TCP_SE= G flag > for all GSO segments after finishes segmenting. Yes, that was my thought too: after successful segmentation we probably=20 need to cleanup related ol_flags. Konstantin > Wonder you and Mark's opinion. >=20 > Thanks, > Jiayu > > > > > > > > I was initially concerned that they might be too coarse-grained (i.e.= only > > IPv4 is currently supported, and not IPv6), but as per Konstantin's > > > previous example, the DEV_TX_OFFLOAD_*_TSO macros can be used in > > concert with the packet type to determine whether a packet should > > > be fragmented or not. > > > > > > Thanks, > > > Mark > > > > > > > > > > >Jiayu > > > >> Konstantin > > > >> > > > >> > > > > >> > The first choice makes HW and SW segmentation are totally the sa= me. > > > >> > Applications just need to parse the packet and set proper ol_fla= gs, and > > > >> > the GSO library uses ol_flags to decide which segmentation funct= ion to > > > >use. > > > >> > I think it's better than the second choice which depending on pt= ype to > > > >> > choose segmentation function. > > > >> > > > > >> > Jiayu > > > >> > > > > > >> > > Konstantin > > > >> > > > > > >> > > > > > > >> > > > Jiayu > > > >> > > > > Konstantin