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GET /api/patches/65793/?format=api
{ "id": 65793, "url": "http://patches.dpdk.org/api/patches/65793/?format=api", "web_url": "http://patches.dpdk.org/project/dpdk/patch/20200213123854.203566-7-gavin.hu@arm.com/", "project": { "id": 1, "url": "http://patches.dpdk.org/api/projects/1/?format=api", "name": "DPDK", "link_name": "dpdk", "list_id": "dev.dpdk.org", "list_email": "dev@dpdk.org", "web_url": "http://core.dpdk.org", "scm_url": "git://dpdk.org/dpdk", "webscm_url": "http://git.dpdk.org/dpdk", "list_archive_url": "https://inbox.dpdk.org/dev", "list_archive_url_format": "https://inbox.dpdk.org/dev/{}", "commit_url_format": "" }, "msgid": "<20200213123854.203566-7-gavin.hu@arm.com>", "list_archive_url": "https://inbox.dpdk.org/dev/20200213123854.203566-7-gavin.hu@arm.com", "date": "2020-02-13T12:38:54", "name": "[RFC,v1,6/6] net/mlx5: relaxed ordering for multi-packet RQ buffer refcnt", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": true, "hash": "efadfc43e4d9031ad52fb1d201510def29d589fe", "submitter": { "id": 1018, "url": "http://patches.dpdk.org/api/people/1018/?format=api", "name": "Gavin Hu", "email": "gavin.hu@arm.com" }, "delegate": { "id": 3268, "url": "http://patches.dpdk.org/api/users/3268/?format=api", "username": "rasland", "first_name": "Raslan", "last_name": "Darawsheh", "email": "rasland@nvidia.com" }, "mbox": "http://patches.dpdk.org/project/dpdk/patch/20200213123854.203566-7-gavin.hu@arm.com/mbox/", "series": [ { "id": 8525, "url": "http://patches.dpdk.org/api/series/8525/?format=api", "web_url": "http://patches.dpdk.org/project/dpdk/list/?series=8525", "date": "2020-02-13T12:38:48", "name": "barrier fix and optimization for mlx5 on aarch64", "version": 1, "mbox": "http://patches.dpdk.org/series/8525/mbox/" } ], "comments": "http://patches.dpdk.org/api/patches/65793/comments/", "check": "success", "checks": "http://patches.dpdk.org/api/patches/65793/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<dev-bounces@dpdk.org>", "X-Original-To": "patchwork@inbox.dpdk.org", "Delivered-To": "patchwork@inbox.dpdk.org", "Received": [ "from dpdk.org (dpdk.org [92.243.14.124])\n\tby inbox.dpdk.org (Postfix) with ESMTP id C66EEA0542;\n\tThu, 13 Feb 2020 13:44:47 +0100 (CET)", "from [92.243.14.124] (localhost [127.0.0.1])\n\tby dpdk.org (Postfix) with ESMTP id 59D0E1BFE5;\n\tThu, 13 Feb 2020 13:44:31 +0100 (CET)", "from foss.arm.com (foss.arm.com [217.140.110.172])\n by dpdk.org (Postfix) with ESMTP id 24F701BFB5;\n Thu, 13 Feb 2020 13:44:30 +0100 (CET)", "from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14])\n by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B37BD1063;\n Thu, 13 Feb 2020 04:44:29 -0800 (PST)", "from net-arm-thunderx2-04.shanghai.arm.com\n (net-arm-thunderx2-04.shanghai.arm.com [10.169.40.184])\n by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 33DCC3F6CF;\n Thu, 13 Feb 2020 04:44:22 -0800 (PST)" ], "From": "Gavin Hu <gavin.hu@arm.com>", "To": "dev@dpdk.org", "Cc": "nd@arm.com, Phil Yang <phil.yang@arm.com>, david.marchand@redhat.com,\n thomas@monjalon.net, rasland@mellanox.com, drc@linux.vnet.ibm.com,\n bruce.richardson@intel.com, konstantin.ananyev@intel.com,\n matan@mellanox.com, shahafs@mellanox.com, viacheslavo@mellanox.com,\n jerinj@marvell.com, Honnappa.Nagarahalli@arm.com, ruifeng.wang@arm.com,\n joyce.kong@arm.com, steve.capper@arm.com, stable@dpdk.org", "Date": "Thu, 13 Feb 2020 20:38:54 +0800", "Message-Id": "<20200213123854.203566-7-gavin.hu@arm.com>", "X-Mailer": "git-send-email 2.17.1", "In-Reply-To": "<20200213123854.203566-1-gavin.hu@arm.com>", "References": "<20200213123854.203566-1-gavin.hu@arm.com>", "Subject": "[dpdk-dev] [PATCH RFC v1 6/6] net/mlx5: relaxed ordering for\n\tmulti-packet RQ buffer refcnt", "X-BeenThere": "dev@dpdk.org", "X-Mailman-Version": "2.1.15", "Precedence": "list", "List-Id": "DPDK patches and discussions <dev.dpdk.org>", "List-Unsubscribe": "<https://mails.dpdk.org/options/dev>,\n <mailto:dev-request@dpdk.org?subject=unsubscribe>", "List-Archive": "<http://mails.dpdk.org/archives/dev/>", "List-Post": "<mailto:dev@dpdk.org>", "List-Help": "<mailto:dev-request@dpdk.org?subject=help>", "List-Subscribe": "<https://mails.dpdk.org/listinfo/dev>,\n <mailto:dev-request@dpdk.org?subject=subscribe>", "Errors-To": "dev-bounces@dpdk.org", "Sender": "\"dev\" <dev-bounces@dpdk.org>" }, "content": "From: Phil Yang <phil.yang@arm.com>\n\nPMD Rx queue descriptor contains two mlx5_mprq_buf fields, which\nare the multi-packet RQ buffer header pointers. It uses the common\nrte_atomic_XXX functions to make sure the refcnt access is atomic.\n\nThe common rte_atomic_XXX functions are full barriers on aarch64.\nOptimized it with one-way barrier to improve performance.\n\nFixes: 7d6bf6b866b8 (\"net/mlx5: add Multi-Packet Rx support\")\nCc: stable@dpdk.org\n\nSuggested-by: Gavin Hu <gavin.hu@arm.com>\nSigned-off-by: Phil Yang <phil.yang@arm.com>\nReviewed-by: Gavin Hu <gavin.hu@arm.com>\n---\n drivers/net/mlx5/mlx5_rxq.c | 2 +-\n drivers/net/mlx5/mlx5_rxtx.c | 16 +++++++++-------\n drivers/net/mlx5/mlx5_rxtx.h | 2 +-\n 3 files changed, 11 insertions(+), 9 deletions(-)", "diff": "diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c\nindex 2d1b153a3..765bb1af5 100644\n--- a/drivers/net/mlx5/mlx5_rxq.c\n+++ b/drivers/net/mlx5/mlx5_rxq.c\n@@ -1535,7 +1535,7 @@ mlx5_mprq_buf_init(struct rte_mempool *mp, void *opaque_arg,\n \n \tmemset(_m, 0, sizeof(*buf));\n \tbuf->mp = mp;\n-\trte_atomic16_set(&buf->refcnt, 1);\n+\t__atomic_store_n(&buf->refcnt, 1, __ATOMIC_RELAXED);\n \tfor (j = 0; j != strd_n; ++j) {\n \t\tshinfo = &buf->shinfos[j];\n \t\tshinfo->free_cb = mlx5_mprq_buf_free_cb;\ndiff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c\nindex 5eea932d4..0e7519c56 100644\n--- a/drivers/net/mlx5/mlx5_rxtx.c\n+++ b/drivers/net/mlx5/mlx5_rxtx.c\n@@ -1592,10 +1592,11 @@ mlx5_mprq_buf_free_cb(void *addr __rte_unused, void *opaque)\n {\n \tstruct mlx5_mprq_buf *buf = opaque;\n \n-\tif (rte_atomic16_read(&buf->refcnt) == 1) {\n+\tif (__atomic_load_n(&buf->refcnt, __ATOMIC_RELAXED) == 1) {\n \t\trte_mempool_put(buf->mp, buf);\n-\t} else if (rte_atomic16_add_return(&buf->refcnt, -1) == 0) {\n-\t\trte_atomic16_set(&buf->refcnt, 1);\n+\t} else if (unlikely(__atomic_sub_fetch(&buf->refcnt, 1,\n+\t\t\t\t\t\t__ATOMIC_RELAXED) == 0)) {\n+\t\t__atomic_store_n(&buf->refcnt, 1, __ATOMIC_RELAXED);\n \t\trte_mempool_put(buf->mp, buf);\n \t}\n }\n@@ -1676,7 +1677,8 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)\n \n \t\tif (consumed_strd == strd_n) {\n \t\t\t/* Replace WQE only if the buffer is still in use. */\n-\t\t\tif (rte_atomic16_read(&buf->refcnt) > 1) {\n+\t\t\tif (__atomic_load_n(&buf->refcnt,\n+\t\t\t\t\t __ATOMIC_RELAXED) > 1) {\n \t\t\t\tmprq_buf_replace(rxq, rq_ci & wq_mask, strd_n);\n \t\t\t\t/* Release the old buffer. */\n \t\t\t\tmlx5_mprq_buf_free(buf);\n@@ -1766,9 +1768,9 @@ mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)\n \t\t\tvoid *buf_addr;\n \n \t\t\t/* Increment the refcnt of the whole chunk. */\n-\t\t\trte_atomic16_add_return(&buf->refcnt, 1);\n-\t\t\tMLX5_ASSERT((uint16_t)rte_atomic16_read(&buf->refcnt) <=\n-\t\t\t\t strd_n + 1);\n+\t\t\t__atomic_add_fetch(&buf->refcnt, 1, __ATOMIC_ACQUIRE);\n+\t\t\tMLX5_ASSERT(__atomic_load_n(&buf->refcnt,\n+\t\t\t\t\t__ATOMIC_RELAXED) <= strd_n + 1);\n \t\t\tbuf_addr = RTE_PTR_SUB(addr, headroom_sz);\n \t\t\t/*\n \t\t\t * MLX5 device doesn't use iova but it is necessary in a\ndiff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h\nindex d32c4e430..1f453fe09 100644\n--- a/drivers/net/mlx5/mlx5_rxtx.h\n+++ b/drivers/net/mlx5/mlx5_rxtx.h\n@@ -78,7 +78,7 @@ struct rxq_zip {\n /* Multi-Packet RQ buffer header. */\n struct mlx5_mprq_buf {\n \tstruct rte_mempool *mp;\n-\trte_atomic16_t refcnt; /* Atomically accessed refcnt. */\n+\tuint16_t refcnt; /* Atomically accessed refcnt. */\n \tuint8_t pad[RTE_PKTMBUF_HEADROOM]; /* Headroom for the first packet. */\n \tstruct rte_mbuf_ext_shared_info shinfos[];\n \t/*\n", "prefixes": [ "RFC", "v1", "6/6" ] }