From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id D92746AAE for ; Fri, 5 Dec 2014 02:10:32 +0100 (CET) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP; 04 Dec 2014 17:09:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,691,1406617200"; d="scan'208";a="493926484" Received: from irsmsx152.ger.corp.intel.com ([163.33.192.66]) by orsmga003.jf.intel.com with ESMTP; 04 Dec 2014 17:07:06 -0800 Received: from irsmsx105.ger.corp.intel.com ([169.254.7.144]) by IRSMSX152.ger.corp.intel.com ([169.254.6.56]) with mapi id 14.03.0195.001; Fri, 5 Dec 2014 01:10:29 +0000 From: "Ananyev, Konstantin" To: Jean-Mickael Guerin , "dev@dpdk.org" Thread-Topic: [PATCH v2] ixgbe: don't override mbuf buffer length Thread-Index: AQHQD+2aqEhfxV/HVEKDZVlTVgxRRZyAKs/g Date: Fri, 5 Dec 2014 01:10:28 +0000 Message-ID: <2601191342CEEE43887BDE71AB977258213BCCB6@IRSMSX105.ger.corp.intel.com> References: <1417716553-1506-1-git-send-email-jean-mickael.guerin@6wind.com> In-Reply-To: <1417716553-1506-1-git-send-email-jean-mickael.guerin@6wind.com> Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.182] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v2] ixgbe: don't override mbuf buffer length X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Dec 2014 01:10:34 -0000 > -----Original Message----- > From: Jean-Mickael Guerin [mailto:jean-mickael.guerin@6wind.com] > Sent: Thursday, December 04, 2014 6:09 PM > To: dev@dpdk.org > Cc: Richardson, Bruce; Ananyev, Konstantin > Subject: [PATCH v2] ixgbe: don't override mbuf buffer length >=20 > The template mbuf_initializer is hard coded with a buflen which > might have been set differently by the application at the time of > mbuf pool creation. >=20 > Switch to a mbuf allocation, to fetch the correct default values. > There is no performance impact because this is not a data-plane API. >=20 > Signed-off-by: Jean-Mickael Guerin > Acked-by: David Marchand > Fixes: 0ff3324da2 ("ixgbe: rework vector pmd following mbuf changes") > --- >=20 > v2: check returned value of ixgbe_rxq_vec_setup >=20 > lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 5 ++++- > lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c | 19 ++++++++++++------- > 2 files changed, 16 insertions(+), 8 deletions(-) >=20 > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixg= be_rxtx.c > index 5c36bff..7994da1 100644 > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > @@ -2244,7 +2244,10 @@ ixgbe_dev_rx_queue_setup(struct rte_eth_dev *dev, > use_def_burst_func =3D check_rx_burst_bulk_alloc_preconditions(rxq); >=20 > #ifdef RTE_IXGBE_INC_VECTOR > - ixgbe_rxq_vec_setup(rxq); > + if (ixgbe_rxq_vec_setup(rxq) < 0) { > + ixgbe_rx_queue_release(rxq); > + return (-ENOMEM); > + } > #endif > /* Check if pre-conditions are satisfied, and no Scattered Rx */ > if (!use_def_burst_func && !dev->data->scattered_rx) { > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe= /ixgbe_rxtx_vec.c > index c1b5a78..f7b02f5 100644 > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c > @@ -732,17 +732,22 @@ static struct ixgbe_txq_ops vec_txq_ops =3D { > int > ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) > { > - struct rte_mbuf mb_def =3D { .buf_addr =3D 0 }; /* zeroed mbuf */ > + struct rte_mbuf *mb_def; >=20 > - mb_def.nb_segs =3D 1; > - mb_def.data_off =3D RTE_PKTMBUF_HEADROOM; > - mb_def.buf_len =3D rxq->mb_pool->elt_size - sizeof(struct rte_mbuf); > - mb_def.port =3D rxq->port_id; > - rte_mbuf_refcnt_set(&mb_def, 1); > + mb_def =3D rte_pktmbuf_alloc(rxq->mb_pool); > + if (mb_def =3D=3D NULL) { > + PMD_INIT_LOG(ERR, "ixgbe_rxq_vec_setup: could not allocate one mbuf"); > + return -1; > + } > + /* nb_segs, refcnt, data_off and buf_len are already set */ > + mb_def->port =3D rxq->port_id; >=20 > /* prevent compiler reordering: rearm_data covers previous fields */ > rte_compiler_barrier(); > - rxq->mbuf_initializer =3D *((uint64_t *)&mb_def.rearm_data); > + rxq->mbuf_initializer =3D *((uint64_t *)&mb_def->rearm_data); > + > + rte_pktmbuf_free(mb_def); > + > return 0; > } >=20 > -- > 2.1.3 As I said in another mail, I don't think it is a proper fix. What we did here - just changed one assumption to another. Current assumption - all mbuf obj_init() would setup buf_len in exactly the= same manner as rte_pktmbuf_init() does: buf_len =3D mp->elt_size - sizeof(struct rte_mbuf); New assumption - all mbuf obj_init() would setup buf_len for all mbufs in t= he pool to the same value. Both assumptions, I believe, are not always correct. Though, probably the new one would be true more often. I still think the proper fix is not to update mbuf's buf_len field at ixgbe= _rxq_rearm() at all. We should just leave the original value unmodified. Actually, while looking at ixgbe_rxq_rearm(), I don't see any reason why we= need to update buf_len field. It is not the data that need to be rearmed. The fields that need to be rearmed are: uint16_t data_off; uint16_t refcnt uint8_t nb_segs; uint8_t port; 6B in total.=20 We probably would like to keep rearming as one 64bit load/store.=20 Though straight below them we have: uint64_t ol_flags; As RX fully override ol_flags anyway, we can safely overwrite first 2B of i= t. That would allow us to still read/write whole 64bits and avoid overwriting = buf_len. =20 I am talking about something like patch below. I admit that it looks not so pretty, but I think it is much safer and corre= ct. Konstantin --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c @@ -79,13 +79,19 @@ ixgbe_rxq_rearm(struct igb_rx_queue *rxq) /* Initialize the mbufs in vector, process 2 mbufs in one loop */ for (i =3D 0; i < RTE_IXGBE_RXQ_REARM_THRESH; i +=3D 2, rxep +=3D 2= ) { __m128i vaddr0, vaddr1; + uintptr_t p0, p1; mb0 =3D rxep[0].mbuf; mb1 =3D rxep[1].mbuf; /* flush mbuf with pkt template */ - mb0->rearm_data[0] =3D rxq->mbuf_initializer; - mb1->rearm_data[0] =3D rxq->mbuf_initializer; + p0 =3D (uintptr_t)&mb0->data_off; + *(uint64_t *)p0 =3D rxq->mbuf_initializer; + p1 =3D (uintptr_t)&mb1->data_off; + *(uint64_t *)p1 =3D rxq->mbuf_initializer; + + //mb0->rearm_data[0] =3D rxq->mbuf_initializer; + //mb1->rearm_data[0] =3D rxq->mbuf_initializer; /* load buf_addr(lo 64bit) and buf_physaddr(hi 64bit) */ vaddr0 =3D _mm_loadu_si128((__m128i *)&(mb0->buf_addr)); @@ -732,6 +738,7 @@ static struct ixgbe_txq_ops vec_txq_ops =3D { int ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) { + uintptr_t p; struct rte_mbuf mb_def =3D { .buf_addr =3D 0 }; /* zeroed mbuf */ mb_def.nb_segs =3D 1; @@ -739,7 +746,8 @@ ixgbe_rxq_vec_setup(struct igb_rx_queue *rxq) mb_def.buf_len =3D rxq->mb_pool->elt_size - sizeof(struct rte_mbuf)= ; mb_def.port =3D rxq->port_id; rte_mbuf_refcnt_set(&mb_def, 1); - rxq->mbuf_initializer =3D *((uint64_t *)&mb_def.rearm_data); + p =3D (uintptr_t)&mb_def.data_off; + rxq->mbuf_initializer =3D *(uint64_t *)p; return 0; }