From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot0-f179.google.com (mail-ot0-f179.google.com [74.125.82.179]) by dpdk.org (Postfix) with ESMTP id 671D93B5 for ; Fri, 17 Mar 2017 08:19:23 +0100 (CET) Received: by mail-ot0-f179.google.com with SMTP id o24so81547417otb.1 for ; Fri, 17 Mar 2017 00:19:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=u5hM32Ds7+/Qm9sMvW1gqr/0ZLxBDiGfSaPe/OxHQuA=; b=troCNMtn8KTcFs77uubvTPs6qfU2OIDaehizhxdcnXmEXmNoOsHL81uem72Mjik2GF xGI3TCcHtIGyvxqxKcDe80SEGIOMTe9N4nKT3M4vkJqWjSzk50mHZX3ViwVO7nKPJxA4 cmunYYoqifsQnIwBhtjL63EeKR6HRbyCKHguj4y09gtN9pOehrZTD2ZpKzMykUk6ouF6 Wou2ome0M4gEWP6m907vu6+iFApzt3+v7vKVu1xYeo7ShEWjuY7xKrGZfmtq+xBMV42d 3zz6t3WuOoOU4v/4yI238kNi0W5Hr8mTYCvFrUKVsIB0TH4FltP68MGyWOp29QW83qxR N17w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=u5hM32Ds7+/Qm9sMvW1gqr/0ZLxBDiGfSaPe/OxHQuA=; b=mEFCbayRYihE6q+GDYO+TIw8lC/HgMEEjxQDZu1KJkbO9FPsRKKOa23o7srG9tzPDR ZKDnNk8iLOJtKn93rv5G065OmowOutZOLVxd+k2a3vj5jr3aACCXH49Gy+Mm/imRuyA1 ZKUQfvJEoD4IMSBgNyElDz2QtO51qrI1eHOG8h1lqZh5DI8wYwfcecCPQbL6S82xj3pE yOJz1ySAXM/VEYevJdhU9Ls9N0EdFbV2eOeagsUO6Mz93E7KjlQVFc2hfV01fYS0A8Df myTTNaSNJpoMkU9qRk4fzzmxPiMC7/8lFxGv9fjyGJMlhpUohUMeOXuKXhZn1vX/4jFX wmig== X-Gm-Message-State: AFeK/H2IgLKL59eCrhu+M+VqAdVlpGJVH07ha/d32mbs/Cb545KTNeA+vg7jUZ3HbdY2blXpRiedyEi/vwY3rA== X-Received: by 10.157.19.102 with SMTP id q35mr7210016otq.234.1489735162425; Fri, 17 Mar 2017 00:19:22 -0700 (PDT) MIME-Version: 1.0 Received: by 10.74.8.84 with HTTP; Fri, 17 Mar 2017 00:19:22 -0700 (PDT) From: ankit bhardwaj Date: Fri, 17 Mar 2017 12:49:22 +0530 Message-ID: To: dev@dpdk.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: [dpdk-dev] Effect of batching done at NIC and in application 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: Fri, 17 Mar 2017 07:19:23 -0000 Hi All, I am using DPDK 16.07 for my use. NIC attached to my server is X520, which is using IXGBE Driver. I am a bit confusion about the batching factor and on what basis it is done. In file "dpdk-16.07/drivers/net/ixgbe/ixgbe_rxtx.h" there are two macros - #define RTE_PMD_IXGBE_TX_MAX_BURST 32 #define RTE_PMD_IXGBE_RX_MAX_BURST 32 which according to me are the batch size at NIC. RTE_PMD_IXGBE_TX_MAX_BURST declares the batch size for transmitting and RTE_PMD_IXGBE_RX_MAX_BURST declares the batch size for receiving. And similarly in the examples, for ex: dpdk-16.07/examples/l2fwd/main.c we are using BURST_SIZE #define MAX_PKT_BURST 32. Now the questions are - Q1: Is my understanding correct about the batch size at NIC and batch size at CPU ? Q2: Why the batch size is 32 and not some other number, shouldn't we decide the batch size depending on the machine configuration ? What are the factors which should be used in deciding the batch size ? I am assuming that latency/per packet is not an issue and we are interested in the throughput. Q3: If first part is not the batch size at NIC, how to add functionality for that ? Thanks Ankit Bhardwaj