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 4D98145AA0 for ; Thu, 3 Oct 2024 17:20:38 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id E9303402B1; Thu, 3 Oct 2024 17:20:37 +0200 (CEST) Received: from mail-pg1-f179.google.com (mail-pg1-f179.google.com [209.85.215.179]) by mails.dpdk.org (Postfix) with ESMTP id 02AC94014F for ; Thu, 3 Oct 2024 17:20:35 +0200 (CEST) Received: by mail-pg1-f179.google.com with SMTP id 41be03b00d2f7-7e9d7960aceso545511a12.1 for ; Thu, 03 Oct 2024 08:20:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1727968835; x=1728573635; 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=PDiaZyGvOz3q5l1mZjrk5VY9gHQX5IGFwyEB0lV+WNw=; b=enWE5auSk6xIEJLDBCmVbW9Lnfb071/HxaoX3qrpbyVJeeFzjYGHXgwvLpILxy8jhQ QdglIlyIDcMScCDoXYYShpHich3H4XAbofqTj7NuaD6dk9lP4IJ8lIatME807n10yF4P 42GjsG0bJ6Y4jW9LvKx3Jkk4od/QKnxxrESpRGDdIxY1cI+IdfCARIQSb9DIfd/hWqlM yP/7yDq2DVpLjXCMeGm1uDGvVZ+7QineugI2Ao5svETXpg42+zt8DgtGzeTh/DZKYy6d kwpcC1ad2osY0SQVzIznYF8MKm24IFTzGyWCk6KDdBH3QmlXKLwfgIlwM9z79o25aEnv xDzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727968835; x=1728573635; 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=PDiaZyGvOz3q5l1mZjrk5VY9gHQX5IGFwyEB0lV+WNw=; b=bpJMPEQUIzxQrbM00HqZbclXgmOJPUScJvbPmWA2r0uM5ypLWYwxuRkdMt8ByIMfXF Fzj3NMGmtAO97UkmlGcO02iWuSHbCrUYlLqaGiX0Re0CebJTxrFluHnTEwFpbdfovC+g rjua821bUTp/nrlOKPK/bAyMxfl1t6qAseO2gOJLjOA9AYmYjwp/LGw9YMStOmb/TFbe nANHKFyua6v90UEiJC3jgEezxbVkhkkg8QMyvbAOTscl4oFK4JmgeLXuKodszllDjiOa 08aep4DZAopOy+kfLmtUephmnB2x2NHRs1vXaJ84BOS3ugjrVjNcCmXbhbWBamHnF8BH AmbQ== X-Forwarded-Encrypted: i=1; AJvYcCVYOfWsX1ALkwolvjfX79xOpzE5iQEXGf2HyH1U9TbcfGCzfhr7a1TquKgps/bm8fA1QDVNHw==@dpdk.org X-Gm-Message-State: AOJu0Ywb3vOKIuxeix5rCtdMzkwYMwWoLYjVfix1x6GeIRaWNw1LRMeE +4nXNk2uzaD2kAQLLzGhVdO88jaaK5XtPeyEKI0IOpZZv5kMPcQgO9JTekS588k= X-Google-Smtp-Source: AGHT+IFhLk8UYQTkY/cVtKf1k/Ftexz9l6PHQUoA434l8J2+NZBDJDVigeSA58JuBwEWNQuMtFlqgg== X-Received: by 2002:a05:6a21:680d:b0:1cf:e5e4:a251 with SMTP id adf61e73a8af0-1d5f241b9c4mr9634387637.47.1727968834866; Thu, 03 Oct 2024 08:20:34 -0700 (PDT) Received: from hermes.local (204-195-96-226.wavecable.com. [204.195.96.226]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71dd9df1205sm1495287b3a.177.2024.10.03.08.20.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Oct 2024 08:20:34 -0700 (PDT) Date: Thu, 3 Oct 2024 08:20:33 -0700 From: Stephen Hemminger To: Dmitry Kozlyuk Cc: Mikael R Carlsson , "Pathak, Pravin" , "users@dpdk.org" Subject: Re: Relation between DPDK queue and descriptors Message-ID: <20241003082033.48d44016@hermes.local> In-Reply-To: <20241003113436.2dc280e7@sovereign> References: <20241002082918.0207a447@hermes.local> <20241003113436.2dc280e7@sovereign> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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, 3 Oct 2024 11:34:36 +0300 Dmitry Kozlyuk wrote: > 2024-10-03 07:37 (UTC+0000), Mikael R Carlsson: > > Hi! > > > > Thanks. > > > > According to chatgpt the descriptors are shared over all TX queues. > > > > So, in a 4 TX queue and 1024 descriptors scenario I would be able to get maximum 256 descriptors per TX queue (If I want same amount on all queues). But if I only used 1 TX queue, I would get all 1024 descriptors on that single TX queue. > > This is not so, ChatGPT errs. > The number of advertised and configured descriptors is per queue > (the latter is per the specific queue being configured, actually). > You won't get more descriptors per queue if you use fewer queues. > Note, however, that queues consume NIC resources and larger queues stress > CPU cache, so it is not always the best to have many queues or large queues. Also, large numbers of descriptors means the mbuf pool much be larger which can exhaust the available huge page memory. If you had 4 Tx queue * 1024 descriptors per queue the Tx side could consume as much as 4K * 2K = 8 Meg of hugepage memory. And on Rx side same applies.