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 D0E7C45CA0 for ; Thu, 7 Nov 2024 17:11:21 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id AD5F542F8F; Thu, 7 Nov 2024 17:11:21 +0100 (CET) Received: from mail-pf1-f177.google.com (mail-pf1-f177.google.com [209.85.210.177]) by mails.dpdk.org (Postfix) with ESMTP id 0AF6542E45 for ; Thu, 7 Nov 2024 17:11:19 +0100 (CET) Received: by mail-pf1-f177.google.com with SMTP id d2e1a72fcca58-71ec997ad06so888510b3a.3 for ; Thu, 07 Nov 2024 08:11:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1730995879; x=1731600679; darn=dpdk.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=laV72bZj5Vu6gGQDsRLvh9BrzVAa6B+CTdwQjnL7CbU=; b=bMMvv9SahwQJMd5wNFYWIA+EQ1jRGbKY1OrcHfyx+J5Fu/RLFG4X6TP74iFQLyxkm5 Y7+qky9Fvy/aOpDxZm/EPBFjIAy3TZK/jN5QszJj1mE8jTkidxxsIj/D2uBqeI5INBAU c+HVx+tQMWYIhDcPMu6hU5hMs7EKkd3jWP9txDP7d2/jmzw+qk4jsqnxWljMMdFH7lzv Z9tDtKrHMzH3Bcq2sw3xCcInoazd08D2kR4PNws+lMP328HfF25yO0LYzw9l4nuebzjW XtBQ9ZiOI6RbHWuzwq2qjsklRaJl2CUCC4WXo8t6oupKdAPbUH84mklSXf758BebStMB 2eOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730995879; x=1731600679; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=laV72bZj5Vu6gGQDsRLvh9BrzVAa6B+CTdwQjnL7CbU=; b=Zs0nWaIdhZF8pn4UbWD4lR7/tj4dVd8ezJvhfLJoUVGnZ7BTv17+8TMJjHzkp1cAki 41AYWCTkQ7UKSkxSw3dUnHRkSClnt2GElSMRcPABSE9PIhDdtFZsT2pFiUpTrZyXp3Sd IAIujyGRlG74dHAgpJN5yPSx5mBVB4b9qJ1TAm90fUJg4k7FkVCdr0uosiyAw+QklZmn MeJM1FVEmjceJCw1gKmGRtus34V9matrsNGPx7O1qCdg1o2O1p+7dvvADFS09y3htwYp 39vfxGaSoZXdjbKxQuxLVoZvfnE+17c3oX9kkDB6X2ZFMVCgizfTy83CZPCj765JhoG2 BcmA== X-Forwarded-Encrypted: i=1; AJvYcCXX7fFKC8/rfrfAcxbKm3laB+SBJ4YYQRewrecTEPnwSXuK0IL1inPc5SEhSAzChPof6KrtpA==@dpdk.org X-Gm-Message-State: AOJu0YwAzkGs786V4wtfw+HLVgIsQHpfB+ZurlX5RWt10PqHkB5nfAF0 w39cEY37//vKPMG44o9AhLsoY0375Y5BaS/osGZRpGL2P5TX9gvWyxRqRFP3Pmk= X-Google-Smtp-Source: AGHT+IGWlFsy9R2MgjZL/a0rbBTVevDBnX1h61BQwR54gk1zM9r9cuRVMwVVuSqX4wZVvCruOL/Yew== X-Received: by 2002:a05:6a00:140d:b0:71e:702c:a680 with SMTP id d2e1a72fcca58-72410de785emr632038b3a.26.1730995879062; Thu, 07 Nov 2024 08:11:19 -0800 (PST) Received: from hermes.local (204-195-96-226.wavecable.com. [204.195.96.226]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-724078a7f22sm1732811b3a.56.2024.11.07.08.11.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Nov 2024 08:11:18 -0800 (PST) Date: Thu, 7 Nov 2024 08:11:16 -0800 From: Stephen Hemminger To: Dmitry Kozlyuk Cc: "Wieckowski, Jacob" , "users@dpdk.org" Subject: Re: DMA Transfers to PCIe Bar Memory Message-ID: <20241107081116.0d777dd1@hermes.local> In-Reply-To: <20241107124225.50c22ee2@sovereign> References: <20241106204604.444529d5@sovereign> <20241107124225.50c22ee2@sovereign> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org On Thu, 7 Nov 2024 12:42:25 +0300 Dmitry Kozlyuk wrote: > rte_memcpy() is intended for copy from RAM to RAM. > You can Cc: Morten Br=C3=B8rup probably, > but I doubt that rte_memcpy() is specialized for DMA in any way. > The buffer may be filled with rte_mempcy() by application, > but this is done before handling the buffer to PMD, and thus before DMA. A little more detail. rte_memcpy() was an attempt at optimization of memcpy(). With current compilers, rte_memcpy() and memcpy() end up producing close to the same code; the only cases left where there is a difference is likely because GCC is more pessemistic about alignment. The plan is to get rid of rte_memcpy() all together.