From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id C99C11B574 for ; Wed, 27 Jun 2018 07:06:04 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Jun 2018 22:06:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,277,1526367600"; d="scan'208";a="235921435" Received: from fmsmsx105.amr.corp.intel.com ([10.18.124.203]) by orsmga005.jf.intel.com with ESMTP; 26 Jun 2018 22:06:01 -0700 Received: from fmsmsx119.amr.corp.intel.com (10.18.124.207) by FMSMSX105.amr.corp.intel.com (10.18.124.203) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 26 Jun 2018 22:06:01 -0700 Received: from shsmsx101.ccr.corp.intel.com (10.239.4.153) by FMSMSX119.amr.corp.intel.com (10.18.124.207) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 26 Jun 2018 22:06:00 -0700 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.223]) by SHSMSX101.ccr.corp.intel.com ([169.254.1.82]) with mapi id 14.03.0319.002; Wed, 27 Jun 2018 13:05:59 +0800 From: "Hu, Jiayu" To: 'Ophir Munk' , "'dev@dpdk.org'" CC: "Wang, Xiao W" , "Ananyev, Konstantin" , "Zhang, Yuwei1" , "Iremonger, Bernard" , 'Thomas Monjalon' Thread-Topic: [dpdk-dev] [PATCH v3 1/3] gso: support UDP/IPv4 fragmentation Thread-Index: AQHUCexYtq8usPu+20et8LBKlmF1tqRyuUcAgACXtVCAAEH9oA== Date: Wed, 27 Jun 2018 05:05:58 +0000 Message-ID: References: <1529205194-87434-1-git-send-email-jiayu.hu@intel.com> <1529646843-45903-1-git-send-email-jiayu.hu@intel.com> <1529646843-45903-2-git-send-email-jiayu.hu@intel.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.200.100 dlp-reaction: no-action x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiYzkyZWFmNzAtZjJmMS00NmYwLTkyY2QtMmU0MjhiZTUyYzNkIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiTG1JUVN3Q2FHakVvSHRGT2NuZHcyYkJLZWNDTlNkMGlteVZoTVM0WlI5MHRtTnZ2MFpcL2Zob3pkRzR5dWRzbUEifQ== x-ctpclassification: CTP_NT x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v3 1/3] gso: support UDP/IPv4 fragmentation X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jun 2018 05:06:05 -0000 > -----Original Message----- > From: Hu, Jiayu > Sent: Wednesday, June 27, 2018 10:29 AM > To: Ophir Munk ; dev@dpdk.org > Cc: Wang, Xiao W ; Ananyev, Konstantin > ; Zhang, Yuwei1 > ; Iremonger, Bernard > ; Thomas Monjalon > > Subject: RE: [dpdk-dev] [PATCH v3 1/3] gso: support UDP/IPv4 > fragmentation >=20 > Hi Ophir, >=20 > Replies are inline. >=20 > > -----Original Message----- > > From: Ophir Munk [mailto:ophirmu@mellanox.com] > > Sent: Wednesday, June 27, 2018 7:59 AM > > To: Hu, Jiayu ; dev@dpdk.org > > Cc: Wang, Xiao W ; Ananyev, Konstantin > > ; Zhang, Yuwei1 > > ; Iremonger, Bernard > > ; Thomas Monjalon > > > > Subject: RE: [dpdk-dev] [PATCH v3 1/3] gso: support UDP/IPv4 > > fragmentation > > > > Hi, > > Please find some comments below. > > > > > -----Original Message----- > > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jiayu Hu > > > Sent: Friday, June 22, 2018 8:54 AM > > > To: dev@dpdk.org > > > Cc: xiao.w.wang@intel.com; konstantin.ananyev@intel.com; > > > yuwei1.zhang@intel.com; bernard.iremonger@intel.com; Thomas > > Monjalon > > > ; Jiayu Hu > > > Subject: [dpdk-dev] [PATCH v3 1/3] gso: support UDP/IPv4 > fragmentation > > > > > > This patch adds GSO support for UDP/IPv4 packets. Supported packets > > may > > > include a single VLAN tag. UDP/IPv4 GSO doesn't check if input packet= s > > have > > > correct checksums, and doesn't update checksums for output packets > (the > > > responsibility for this lies with the application). > > > Additionally, UDP/IPv4 GSO doesn't process IP fragmented packets. > > > > > > UDP/IPv4 GSO uses two chained MBUFs, one direct MBUF and one > indrect > > > MBUF, to organize an output packet. The direct MBUF stores the packet > > > header, while the indirect mbuf simply points to a location within th= e > > original > > > packet's payload. Consequently, use of UDP GSO requires multi-segment > > > MBUF support in the TX functions of the NIC driver. > > > > > > If a packet is GSO'd, UDP/IPv4 GSO reduces its MBUF refcnt by 1. As a > > result, > > > when all of its GSOed segments are freed, the packet is freed > > automatically. > > > > > > Signed-off-by: Jiayu Hu > > > --- > > > lib/librte_gso/Makefile | 1 + > > > lib/librte_gso/gso_common.h | 3 ++ > > > lib/librte_gso/gso_udp4.c | 81 > > > +++++++++++++++++++++++++++++++++++++++++++++ > > > lib/librte_gso/gso_udp4.h | 42 +++++++++++++++++++++++ > > > lib/librte_gso/meson.build | 2 +- > > > lib/librte_gso/rte_gso.c | 24 +++++++++++--- > > > lib/librte_gso/rte_gso.h | 6 +++- > > > 7 files changed, 152 insertions(+), 7 deletions(-) create mode 1006= 44 > > > lib/librte_gso/gso_udp4.c create mode 100644 > lib/librte_gso/gso_udp4.h > > > > > > diff --git a/lib/librte_gso/Makefile b/lib/librte_gso/Makefile index > > > 3648ec0..1fac53a 100644 > > > --- a/lib/librte_gso/Makefile > > > +++ b/lib/librte_gso/Makefile > > > @@ -19,6 +19,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_GSO) +=3D rte_gso.c > > > SRCS-$(CONFIG_RTE_LIBRTE_GSO) +=3D gso_common.c > > > SRCS-$(CONFIG_RTE_LIBRTE_GSO) +=3D gso_tcp4.c > > > SRCS-$(CONFIG_RTE_LIBRTE_GSO) +=3D gso_tunnel_tcp4.c > > > +SRCS-$(CONFIG_RTE_LIBRTE_GSO) +=3D gso_udp4.c > > > > > > # install this header file > > > SYMLINK-$(CONFIG_RTE_LIBRTE_GSO)-include +=3D rte_gso.h diff --git > > > a/lib/librte_gso/gso_common.h b/lib/librte_gso/gso_common.h index > > > 5ca5974..6cd764f 100644 > > > --- a/lib/librte_gso/gso_common.h > > > +++ b/lib/librte_gso/gso_common.h > > > @@ -31,6 +31,9 @@ > > > (PKT_TX_TCP_SEG | PKT_TX_IPV4 | PKT_TX_OUTER_IPV4 | > > \ > > > PKT_TX_TUNNEL_GRE)) > > > > > > +#define IS_IPV4_UDP(flag) (((flag) & (PKT_TX_UDP_SEG | PKT_TX_IPV4)) > > =3D=3D > > > \ > > > + (PKT_TX_UDP_SEG | PKT_TX_IPV4)) > > > + > > > /** > > > * Internal function which updates the UDP header of a packet, > following > > > * segmentation. This is required to update the header's datagram > length > > > field. > > > diff --git a/lib/librte_gso/gso_udp4.c b/lib/librte_gso/gso_udp4.c ne= w > file > > > mode 100644 index 0000000..927dee1 > > > --- /dev/null > > > +++ b/lib/librte_gso/gso_udp4.c > > > > File gso_upd4.c could be very similar to file gso_tcp4.c and that would > > avoid code duplication. > > In a unified file you could use a tcp vs. udp flag to distinguish betwe= en > them > > when necessary. > > The files are short (~75 lines) so it is not a critical issue. >=20 > The function gso_tcp4_segment and gso_udp4_segment have different > prototype, > and their GSO rules are different. They are two different basic GSO types= . >=20 > The GSO library gives each GSO type (TCP, tunnel) an internal .c and .h f= ile, > and their name > represents their content. The rte_gso_segment calls different function > according to the GSO type. > This style is very clear for developers or users to understand. In additi= on, as > you said, the code > is short. So I think it's better to keep this style for UDP/IPv4 GSO. >=20 > > > > > @@ -0,0 +1,81 @@ > > > +/* SPDX-License-Identifier: BSD-3-Clause > > > + * Copyright(c) 2018 Intel Corporation > > > + */ > > > + > > > +#include "gso_common.h" > > > +#include "gso_udp4.h" > > > + > > > +#define IPV4_HDR_MF_BIT (1U << 13) > > > + > > > +static inline void > > > +update_ipv4_udp_headers(struct rte_mbuf *pkt, struct rte_mbuf > **segs, > > > + uint16_t nb_segs) > > > +{ > > > + struct ipv4_hdr *ipv4_hdr; > > > + uint16_t frag_offset =3D 0, is_mf; > > > + uint16_t l2_hdrlen =3D pkt->l2_len, l3_hdrlen =3D pkt->l3_len; > > > + uint16_t tail_idx =3D nb_segs - 1, length, i; > > > + > > > + /* > > > + * Update IP header fields for output segments. Specifically, > > > + * keep the same IP id, update fragment offset and total > > > + * length. > > > + */ > > > + for (i =3D 0; i < nb_segs; i++) { > > > + ipv4_hdr =3D rte_pktmbuf_mtod_offset(segs[i], struct > > ipv4_hdr > > > *, > > > + l2_hdrlen); > > > + length =3D segs[i]->pkt_len - l2_hdrlen; > > > + ipv4_hdr->total_length =3D rte_cpu_to_be_16(length); > > > + > > > + is_mf =3D i < tail_idx ? IPV4_HDR_MF_BIT : 0; > > > + ipv4_hdr->fragment_offset =3D > > > + rte_cpu_to_be_16(frag_offset | is_mf); > > > + frag_offset +=3D ((length - l3_hdrlen) >> 3); > > > + } > > > +} > > > + > > > +int > > > +gso_udp4_segment(struct rte_mbuf *pkt, > > > + uint16_t gso_size, > > > + struct rte_mempool *direct_pool, > > > + struct rte_mempool *indirect_pool, > > > + struct rte_mbuf **pkts_out, > > > + uint16_t nb_pkts_out) > > > +{ > > > + struct ipv4_hdr *ipv4_hdr; > > > + uint16_t pyld_unit_size, hdr_offset; > > > + uint16_t frag_off; > > > + int ret; > > > + > > > + /* Don't process the fragmented packet */ > > > + ipv4_hdr =3D rte_pktmbuf_mtod_offset(pkt, struct ipv4_hdr *, > > > + pkt->l2_len); > > > + frag_off =3D rte_be_to_cpu_16(ipv4_hdr->fragment_offset); > > > + if (unlikely(IS_FRAGMENTED(frag_off))) { > > > + pkts_out[0] =3D pkt; > > > + return 1; > > > + } > > > + > > > + /* > > > + * UDP fragmentation is the same as IP fragmentation. > > > + * Except the first one, other output packets just have l2 > > > + * and l3 headers. > > > + */ > > > + hdr_offset =3D pkt->l2_len + pkt->l3_len; > > > + > > > + /* Don't process the packet without data. */ > > > + if (unlikely(hdr_offset + pkt->l4_len >=3D pkt->pkt_len)) { > > > + pkts_out[0] =3D pkt; > > > + return 1; > > > + } > > > + > > > + pyld_unit_size =3D gso_size - hdr_offset; > > > + > > > + /* Segment the payload */ > > > + ret =3D gso_do_segment(pkt, hdr_offset, pyld_unit_size, direct_pool= , > > > + indirect_pool, pkts_out, nb_pkts_out); > > > + if (ret > 1) > > > + update_ipv4_udp_headers(pkt, pkts_out, ret); > > > + > > > + return ret; > > > +} > > > diff --git a/lib/librte_gso/gso_udp4.h b/lib/librte_gso/gso_udp4.h ne= w > file > > > mode 100644 index 0000000..b2a2908 > > > > File gso_upd4.h is almost identical to file gso_tcp4.h so both files > (although > > short ~40 lines) could have been unified into one file. >=20 > Ditto. >=20 > > > > > --- /dev/null > > > +++ b/lib/librte_gso/gso_udp4.h > > > @@ -0,0 +1,42 @@ > > > +/* SPDX-License-Identifier: BSD-3-Clause > > > + * Copyright(c) 2018 Intel Corporation > > > + */ > > > + > > > +#ifndef _GSO_UDP4_H_ > > > +#define _GSO_UDP4_H_ > > > + > > > +#include > > > +#include > > > + > > > +/** > > > + * Segment an UDP/IPv4 packet. This function doesn't check if the > input > > > + * packet has correct checksums, and doesn't update checksums for > > > +output > > > + * GSO segments. Furthermore, it doesn't process IP fragment packets= . > > > + * > > > + * @param pkt > > > + * The packet mbuf to segment. > > > + * @param gso_size > > > + * The max length of a GSO segment, measured in bytes. > > > + * @param direct_pool > > > + * MBUF pool used for allocating direct buffers for output segments= . > > > + * @param indirect_pool > > > + * MBUF pool used for allocating indirect buffers for output segmen= ts. > > > + * @param pkts_out > > > + * Pointer array used to store the MBUF addresses of output GSO > > > + * segments, when the function succeeds. If the memory space in > > > + * pkts_out is insufficient, it fails and returns -EINVAL. > > > + * @param nb_pkts_out > > > + * The max number of items that 'pkts_out' can keep. > > > + * > > > + * @return > > > + * - The number of GSO segments filled in pkts_out on success. > > > + * - Return -ENOMEM if run out of memory in MBUF pools. > > > + * - Return -EINVAL for invalid parameters. > > > + */ > > > +int gso_udp4_segment(struct rte_mbuf *pkt, > > > + uint16_t gso_size, > > > + struct rte_mempool *direct_pool, > > > + struct rte_mempool *indirect_pool, > > > + struct rte_mbuf **pkts_out, > > > + uint16_t nb_pkts_out); > > > +#endif > > > diff --git a/lib/librte_gso/meson.build b/lib/librte_gso/meson.build > index > > > 056534f..ad8dd85 100644 > > > --- a/lib/librte_gso/meson.build > > > +++ b/lib/librte_gso/meson.build > > > @@ -1,7 +1,7 @@ > > > # SPDX-License-Identifier: BSD-3-Clause # Copyright(c) 2017 Intel > > > Corporation > > > > > > -sources =3D files('gso_common.c', 'gso_tcp4.c', > > > +sources =3D files('gso_common.c', 'gso_tcp4.c', 'gso_udp4.c', > > > 'gso_tunnel_tcp4.c', 'rte_gso.c') > > > headers =3D files('rte_gso.h') > > > deps +=3D ['ethdev'] > > > diff --git a/lib/librte_gso/rte_gso.c b/lib/librte_gso/rte_gso.c inde= x > > > a44e3d4..751b5b6 100644 > > > --- a/lib/librte_gso/rte_gso.c > > > +++ b/lib/librte_gso/rte_gso.c > > > @@ -11,6 +11,17 @@ > > > #include "gso_common.h" > > > #include "gso_tcp4.h" > > > #include "gso_tunnel_tcp4.h" > > > +#include "gso_udp4.h" > > > + > > > +#define ILLEGAL_UDP_GSO_CTX(ctx) \ > > > + ((((ctx)->gso_types & DEV_TX_OFFLOAD_UDP_TSO) =3D=3D 0) || \ > > > + (ctx)->gso_size < RTE_GSO_UDP_SEG_SIZE_MIN) > > > + > > > +#define ILLEGAL_TCP_GSO_CTX(ctx) \ > > > + ((((ctx)->gso_types & (DEV_TX_OFFLOAD_TCP_TSO | \ > > > + DEV_TX_OFFLOAD_VXLAN_TNL_TSO | \ > > > + DEV_TX_OFFLOAD_GRE_TNL_TSO)) =3D=3D 0) || \ > > > + (ctx)->gso_size < RTE_GSO_SEG_SIZE_MIN) > > > > Can you please explain why it is correct that the min len for VXLAN_TNL > or > > GRE_TNL is that of TCP MIN size (RTE_GSO_SEG_SIZE_MIN) >=20 > The logic here is a little complicated. First, we have two GSO types, i.e= . TCP > and UDP, > and they have different requirements for min lengths and gso_types flags. > In the code, > we use ILLEGAL_UDP_GSO_CTX() and ILLEGAL_TCP_GSO_CTX() to check if > the input packet > doesn't meet the requirements. Rte_gso_segment() starts to process the > input packet only > when it meets UDP or TCP requirement. In other words, rte_gso_segment() > stops if the > packet doesn't meet both requirements at the same time. This is why I use > " ILLEGAL_UDP_GSO_CTX(gso_ctx) && ILLEGAL_TCP_GSO_CTX(gso_ctx))" > as the exit > condition. >=20 > RTE_GSO_SEG_SIZE_MIN is not used to decide if input tunnel packets meet > length > requirement, but just checks a min length. In fact, we cannot decide a re= al > correct min > length for a packet type, since it may have vlan header or not. The origi= nal > GSO code > leverages this macro for tunnel packets to do a minimal check, so I think= we > can keep it > here. >=20 > > > > > > > > > To make the macros above and their usage below clearer: > > > > 1. I would change the || with &&. and =3D=3D with !=3D > > > > #define ILLEGAL_UDP_GSO_CTX(ctx) \ > > ((((ctx)->gso_types & DEV_TX_OFFLOAD_UDP_TSO) !=3D 0) && \ > > (ctx)->gso_size < RTE_GSO_UDP_SEG_SIZE_MIN) >=20 > This macro doesn't check all conditions for illegal UDP GSO. For example, > if we input a UDP/IPv4 packet with setting gso_size to 1500 and without > setting > DEV_TX_OFFLOAD_UDP_TSO in gso_types, this macro returns 0, which > means > it's a legal UDP GSO packet. >=20 > If you mean we'd better use LEGAL rather than ILLEGAL as the check in the > code, > the exit condition should be: >=20 > #define LEGAL_UDP_GSO_CTX(ctx) \ > ((((ctx)->gso_types & DEV_TX_OFFLOAD_UDP_TSO) !=3D 0) && \ > (ctx)->gso_size >=3D RTE_GSO_UDP_SEG_SIZE_MIN) >=20 > if (~(LEGAL_UDP_GSO_CTX(..) || LEGAL_TCP_GSO_CTX(..))) > return -EINVAL; >=20 > But in fact, it's the same as current implementation. I can add some > explanations to the code for users to better understand the logic, if you > think it's OK. >=20 > > > > #define ILLEGAL_TCP_GSO_CTX(ctx) \ > > ((((ctx)->gso_types & (DEV_TX_OFFLOAD_TCP_TSO | \ > > DEV_TX_OFFLOAD_VXLAN_TNL_TSO | \ > > DEV_TX_OFFLOAD_GRE_TNL_TSO)) !=3D 0) && \ > > (ctx)->gso_size < RTE_GSO_SEG_SIZE_MIN) > > >=20 > Ditto. >=20 > > 2. Then later I would change the && with || > > > > Changing original: > > (ILLEGAL_UDP_GSO_CTX(gso_ctx) && > > ILLEGAL_TCP_GSO_CTX(gso_ctx))) > > > > With this: > > ILLEGAL_UDP_GSO_CTX(gso_ctx) || > > ILLEGAL_TCP_GSO_CTX(gso_ctx)) >=20 > Ditto. >=20 > > > > > > > int > > > rte_gso_segment(struct rte_mbuf *pkt, > > > @@ -27,14 +38,12 @@ rte_gso_segment(struct rte_mbuf *pkt, > > > > > > if (pkt =3D=3D NULL || pkts_out =3D=3D NULL || gso_ctx =3D=3D NULL = || > > > nb_pkts_out < 1 || > > > - gso_ctx->gso_size < RTE_GSO_SEG_SIZE_MIN || > > > - ((gso_ctx->gso_types & > > > (DEV_TX_OFFLOAD_TCP_TSO | > > > - DEV_TX_OFFLOAD_VXLAN_TNL_TSO | > > > - DEV_TX_OFFLOAD_GRE_TNL_TSO)) =3D=3D 0)) > > > + (ILLEGAL_UDP_GSO_CTX(gso_ctx) && > > > + ILLEGAL_TCP_GSO_CTX(gso_ctx))) > > > return -EINVAL; > > > > > > if (gso_ctx->gso_size >=3D pkt->pkt_len) { > > > - pkt->ol_flags &=3D (~PKT_TX_TCP_SEG); > > > + pkt->ol_flags &=3D (~(PKT_TX_TCP_SEG | PKT_TX_UDP_SEG)); > > > pkts_out[0] =3D pkt; > > > return 1; > > > } > > > @@ -59,6 +68,11 @@ rte_gso_segment(struct rte_mbuf *pkt, > > > ret =3D gso_tcp4_segment(pkt, gso_size, ipid_delta, > > > direct_pool, indirect_pool, > > > pkts_out, nb_pkts_out); > > > + } else if (IS_IPV4_UDP(pkt->ol_flags) && > > > + (gso_ctx->gso_types & > > > DEV_TX_OFFLOAD_UDP_TSO)) { > > > + pkt->ol_flags &=3D (~PKT_TX_UDP_SEG); > > > + ret =3D gso_udp4_segment(pkt, gso_size, direct_pool, > > > + indirect_pool, pkts_out, nb_pkts_out); > > > } else { > > > /* unsupported packet, skip */ > > > pkts_out[0] =3D pkt; > > > diff --git a/lib/librte_gso/rte_gso.h b/lib/librte_gso/rte_gso.h inde= x > > > f4abd61..a626a11 100644 > > > --- a/lib/librte_gso/rte_gso.h > > > +++ b/lib/librte_gso/rte_gso.h > > > @@ -17,10 +17,14 @@ extern "C" { > > > #include > > > #include > > > > > > -/* Minimum GSO segment size. */ > > > +/* Minimum GSO segment size for TCP based packets. */ > > > #define RTE_GSO_SEG_SIZE_MIN (sizeof(struct ether_hdr) + \ > > > sizeof(struct ipv4_hdr) + sizeof(struct tcp_hdr) + 1) > > > > RTE_GSO_SEG_SIZE_MIN is actually TCP min size. Can you name this > macro > > as > > RTE_GSO_TCP_SEG_SIZE_MIN (symmetrically to the UDP macro below)? > > >=20 > Yes, you are right. The name is not good. But I don't know if changing na= me > will introduce ABI change, so I select this name as a workaround. Sorry, it will not cause ABI change but will influence the applications which have already used the GSO library, if we rename RTE_GSO_SEG_SIZE_MIN. This is because this macro is an external macro. From my perspective, I pre= fer to introduce a new macro for UDP based GSO, instead of renaming it. Jiayu >=20 > Thanks, > Jiayu >=20 > > > > > > +/* Minimum GSO segment size for UDP based packets. */ #define > > > +RTE_GSO_UDP_SEG_SIZE_MIN (sizeof(struct ether_hdr) + \ > > > + sizeof(struct ipv4_hdr) + sizeof(struct udp_hdr) + 1) > > > + > > > /* GSO flags for rte_gso_ctx. */ > > > #define RTE_GSO_FLAG_IPID_FIXED (1ULL << 0) /**< Use fixed IP ids > for > > > output GSO segments. Setting > > > -- > > > 2.7.4