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 3E203A00C4; Wed, 28 Sep 2022 14:52:57 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 359AA41140; Wed, 28 Sep 2022 14:52:57 +0200 (CEST) Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com [209.85.221.44]) by mails.dpdk.org (Postfix) with ESMTP id B02804280C for ; Wed, 28 Sep 2022 14:52:55 +0200 (CEST) Received: by mail-wr1-f44.google.com with SMTP id v28so6816518wrd.3 for ; Wed, 28 Sep 2022 05:52:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind.com; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date; bh=31wJPIKWg3Fk8Edmpn4Tp3kO4c2IWpqgax/Z6BYFs6I=; b=GiaAYkLSJgNI3vnmh+GOaApIsBWFv2dEX3V/rc0rNsl3kH4/ffzdviVjbIeAr99F0L qAtwJ7jMbCtF34W5KdnWh+7fg80YuqrZAwhKRpOyBi+Bw8iEcIZf9xcGRVJ+M4MGC03W 2xgQNCBMRKKOEn1k9+ONqOm+2LpRTBcOuCL8RzCfR7naxDDkRBRhFvNRK0z9m+TwW1BP EFZGX7voqarix3oEj07cdkftGv6vujrHI33KfRaKqTW+yxl1llyt+vYRyO198afM2jOP e7wuw8V1lAXdaBkASFY0zRspzAtJm4qMu09sD24BpF7a7aWgkRlc5FjH8dyJQpwTuk99 e4Tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date; bh=31wJPIKWg3Fk8Edmpn4Tp3kO4c2IWpqgax/Z6BYFs6I=; b=ru/3o/Kgdb+Koucbt+KapP02L+8n9pBCfuaijUxgC4HIullBpf3XPX2XwTWzi7kqcP RmvLcBVnnO34TBn+qVNPPM8NGfV4ZbGSjGKkyTNxNCZh4P5oBOrPfRPTPzQg4Z2K97NO 5MEQd6iG52SBocCvZtIAStpS/+MsYq14lzdw4IfTp+K4+taYpJWArG/3Ea0eprgi7cjn dIFjnUktIPvXZP1e7Vlp75vyNCACbXLxFwAL9ifnZuSE/wVKv3g/ViK0yihgFodWOUhK g4QtNyqNnOOI83oQboXuuD55G46e6an6Tq2Nyd/maKwU9qMugkMesT4ReDpQtcHGNrp5 WSAw== X-Gm-Message-State: ACrzQf2OczdHpkSo4t59dQzFCfLY3b0hjH0utK44EAajZBw2yxN6oKoZ B1CdO+ziQPhgciPxfgPvDz0YPA== X-Google-Smtp-Source: AMsMyM4myPYfPAub8hcBzwdYWLUAhyCWl8zKYtknwtZ5h1k/cELowl4vZa6Lsh2u2O5ezPLn517MFQ== X-Received: by 2002:a5d:46c7:0:b0:22c:c9e5:4e4e with SMTP id g7-20020a5d46c7000000b0022cc9e54e4emr1660391wrs.37.1664369575399; Wed, 28 Sep 2022 05:52:55 -0700 (PDT) Received: from 6wind.com ([2a01:e0a:5ac:6460:c065:401d:87eb:9b25]) by smtp.gmail.com with ESMTPSA id a20-20020a05600c069400b003a5fa79007fsm1607041wmn.7.2022.09.28.05.52.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Sep 2022 05:52:55 -0700 (PDT) Date: Wed, 28 Sep 2022 14:52:54 +0200 From: Olivier Matz To: Shijith Thotton Cc: dev@dpdk.org, pbhagavatula@marvell.com, Honnappa.Nagarahalli@arm.com, bruce.richardson@intel.com, jerinj@marvell.com, mb@smartsharesystems.com, stephen@networkplumber.org, thomas@monjalon.net, david.marchand@redhat.com Subject: Re: [PATCH v3 3/5] lib: move mbuf next pointer to first cache line Message-ID: References: <20220907134340.3629224-1-sthotton@marvell.com> <7cc8107a4a83dbfe16abd1f24150b0db6cf1041b.1663767715.git.sthotton@marvell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7cc8107a4a83dbfe16abd1f24150b0db6cf1041b.1663767715.git.sthotton@marvell.com> 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, Sep 21, 2022 at 07:26:19PM +0530, Shijith Thotton wrote: > Swapped position of mbuf next pointer and second dynamic field (dynfield2) > if the build is configured to use IOVA as VA. This is to move the mbuf > next pointer to first cache line. kni library is disabled for this > change as it depends on the offset value of next pointer. > > Signed-off-by: Shijith Thotton > --- > lib/mbuf/rte_mbuf_core.h | 29 +++++++++++++++++++++-------- > lib/meson.build | 3 +++ > 2 files changed, 24 insertions(+), 8 deletions(-) > > diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h > index 94907f301d..915dcd8653 100644 > --- a/lib/mbuf/rte_mbuf_core.h > +++ b/lib/mbuf/rte_mbuf_core.h > @@ -590,11 +590,14 @@ struct rte_mbuf { > * working on vector drivers easier. > */ > rte_iova_t buf_iova __rte_aligned(sizeof(rte_iova_t)); > +#if RTE_IOVA_AS_VA > /** > - * Reserved for dynamic field in builds where physical address > - * field is invalid. > + * Next segment of scattered packet. > + * This field is valid when physical address field is invalid. > + * Otherwise next pointer in the second cache line will be used. > */ > - uint64_t dynfield2; > + struct rte_mbuf *next; > +#endif > }; > > /* next 8 bytes are initialised on RX descriptor rearm */ > @@ -711,11 +714,21 @@ struct rte_mbuf { > /* second cache line - fields only used in slow path or on TX */ > RTE_MARKER cacheline1 __rte_cache_min_aligned; > > - /** > - * Next segment of scattered packet. Must be NULL in the last segment or > - * in case of non-segmented packet. > - */ > - struct rte_mbuf *next; > + RTE_STD_C11 > + union { > +#if !RTE_IOVA_AS_VA > + /** > + * Next segment of scattered packet. Must be NULL in the last > + * segment or in case of non-segmented packet. > + */ > + struct rte_mbuf *next; > +#endif > + /** > + * Reserved for dynamic field when the next pointer is in first > + * cache line (i.e. RTE_IOVA_AS_VA is 1). > + */ > + uint64_t dynfield2; > + }; Same comment than other patches about union vs #if. > > /* fields to support TX offloads */ > RTE_STD_C11 > diff --git a/lib/meson.build b/lib/meson.build > index c648f7d800..73d93bc803 100644 > --- a/lib/meson.build > +++ b/lib/meson.build > @@ -88,6 +88,9 @@ optional_libs = [ > disabled_libs = [] > opt_disabled_libs = run_command(list_dir_globs, get_option('disable_libs'), > check: true).stdout().split() > +if dpdk_conf.get('RTE_IOVA_AS_VA') == 1 > + opt_disabled_libs += ['kni'] > +endif I guess this should be in the previous patch instead, since kni uses m->buf_iova > foreach l:opt_disabled_libs > if not optional_libs.contains(l) > warning('Cannot disable mandatory library "@0@"'.format(l)) After this change, the documentation of RTE_IOVA_AS_VA can be enhanced to explain that it also moves the next pointer to the first cache line, possibly increasing the performance.