From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 202ABA00C2; Wed, 9 Feb 2022 23:46:22 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id A4EDF41101; Wed, 9 Feb 2022 23:46:21 +0100 (CET) Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) by mails.dpdk.org (Postfix) with ESMTP id 04BA140140 for ; Wed, 9 Feb 2022 23:46:21 +0100 (CET) Received: by mail-pl1-f180.google.com with SMTP id 10so235622plj.1 for ; Wed, 09 Feb 2022 14:46:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vBd581JeguMNZo3s7W0/Kp0RNso9ftTHmMFNZb673Fc=; b=h3bxGeoj/Iw/155SMDXa6XOGKXvVXyGlf9rIBtb0S7gy+Ysi3+2ApEiR8x0JnEXICM kRX2yUnRbHrykbs7CIRrIzIdoJce4I/gFUG4MnzITaO3sVns6mX4hT+JN+I2SPXp0BVL J+C2gKggKOW+vZKncUXWn/z2xUBYowUVP/xsVf/tyDYMdozEwsIX0MMepoSxYP99xFyZ JoA5igipYETpb3Suyh0RNbUE2al+dpZ1qMwKB4ZJXay0+TNXl7z2YdHF1FwAZGCt3m0I 8XcZ2mjRLO7CQmSpmfnMEuW31dv+HdyqaWA5Tn5y4krsmI+AhppaeMEJhhnEoWbC2/E5 K/vg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=vBd581JeguMNZo3s7W0/Kp0RNso9ftTHmMFNZb673Fc=; b=euVN7TQL9bikMn2qAWOLhn0oNM4x92ksYYk0zOjoqa8Uoo0mI5SETB1MxlZOf6GAas OlxP8QFA9r4ZlRY4bThN+T3t24K6E4j7X0+kmxnTAeLYJYU+PSLPYJSPkZ2gDzEJMF3s yPqiQ0sxzWGhQKAd3vsfe7MJQ4/4skR7yCq5KyWnj78qI7aGEkec5LkpikGUqpsogpsq JVJ91vvs5zjNYALVnJql48kz/2mr47MkhjrCZG0cB6vau/pIWYV/d8FgsgFAHxBPONyd WhZBmFqY0w+coOeArvd0CMwfYW4m3cZQC451GbvN3ih29UDB0Ps5qokG0QbjE9Is9rJI GPLQ== X-Gm-Message-State: AOAM531eXq1AidjWeB/rPS5kpt26hduK2WuSfJ8XhaeEy3aScNDaML69 xp/IFmrrfKDObswj3KioKMalow== X-Google-Smtp-Source: ABdhPJyzUZuvYtVuYnSbXDXwPj6qV1xB1Aa5BkAyboKNzQoD2KC7D/+x5IauVaCx0EyiWxdDw2MVJA== X-Received: by 2002:a17:902:ce04:: with SMTP id k4mr4483878plg.62.1644446780179; Wed, 09 Feb 2022 14:46:20 -0800 (PST) Received: from hermes.local (204-195-112-199.wavecable.com. [204.195.112.199]) by smtp.gmail.com with ESMTPSA id t7sm20645394pfj.138.2022.02.09.14.46.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Feb 2022 14:46:19 -0800 (PST) Date: Wed, 9 Feb 2022 14:46:17 -0800 From: Stephen Hemminger To: Ferruh Yigit Cc: Ansar Kannankattil , Subject: Re: Can I use rte_pktmbuf_chain to chain multiple mbuffs for calling only single tx_eth_burst API Message-ID: <20220209144617.79834bd6@hermes.local> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Wed, 9 Feb 2022 22:18:24 +0000 Ferruh Yigit wrote: > On 2/9/2022 6:03 PM, Ansar Kannankattil wrote: > > Hi > > My intention is to decrease the number of rte_tx_eth_burst calls, I kno= w that mentioning nb_pkts will result in sending multiple packets in a sing= le call. > > But providing nb_pkts=3D1 and posting a head mbuff having number of mbu= ffs=C2=A0linked with it will results sending multiple=C2=A0packets =20 >=20 > If driver supports, you can do it. > Driver should expose this capability via RTE_ETH_TX_OFFLOAD_MULTI_SEGS fl= ag, > in 'dev_info->tx_offload_capa'. >=20 > > If not, what is the use case of linking multiple mbuffs=C2=A0together = =20 >=20 > It is also used in Rx path (again if driver supports). I think Ansar was asking about chaining multiple packets in one call to tx = burst. The chaining in DPDK is to make a single packet out of multiple pieces (lik= e writev). DPDK mbufs were based on original BSD concept. In BSD mbufs, mbuf has two linked lists. BSD m->m_next pointer =3D=3D DPDK m->next for multiple parts of packet. BSD m->m_nextpkt for next packet in queue There is no nextpkt in DPDK.