From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9EBAAC5AE59 for ; Thu, 29 May 2025 16:37:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=wgchDy6+ENMwqS/G43COtFv0WHKtbEpVBzFuObLQORs=; b=vSIGqsFY3AngUxbv77Hrpnm/MH IC67A5vKZwOR4eN0y4Ya0Rnao+z61CxQfR3z3J/LN7gzAVTU6K6UMDO7cZmP/4ERLlw7/2pBNN0sg cBKgCoYIEmz10G3iwTaWSOnpuWRCjcAyUo33pk7Pgow2cP8NqDV3ymzk43voPwKsCPf8SD3K1z6H0 tFVo0nU1OTWGJOCIG/CTAKKH0xJsIswm1zDbM4EA1vhSLuL1Ks+2JaUMmhKrOYpio8Y+TPk52lZ7b htqi7YS8cflvVo6h+QSvFDY+ZN/vfgmCIXnWxjyVzsDQor/FIusI/bzAMbAdzvNXumv7nXG/6FXDi +uragOMg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uKgG2-0000000GCR1-2ded; Thu, 29 May 2025 16:37:30 +0000 Received: from out-189.mta0.migadu.com ([2001:41d0:1004:224b::bd]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uKgDt-0000000GCFr-4ATM for linux-arm-kernel@lists.infradead.org; Thu, 29 May 2025 16:35:19 +0000 Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1748536513; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wgchDy6+ENMwqS/G43COtFv0WHKtbEpVBzFuObLQORs=; b=hqLZDpOWSYQ2FckvbhD5AL4P/5BzRpqjbhLUkGbGbVjsd4GxGVI2nKradu011PJcE3efzT VQi7WkK/+LrbhVboZKk9NzMSWHnauDVyZz3HkGFKQD4Fy/xbTNNrc0TMuLvtbBjK8Yf/NP E9xhQ00BqTYAH6m9BUGtxaWj3Ih+YQA= Date: Thu, 29 May 2025 12:35:09 -0400 MIME-Version: 1.0 Subject: Re: [PATCH net-next] net: xilinx: axienet: Configure and report coalesce parameters in DMAengine flow To: Andrew Lunn Cc: "Gupta, Suraj" , "andrew+netdev@lunn.ch" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "vkoul@kernel.org" , "Simek, Michal" , "Pandey, Radhey Shyam" , "horms@kernel.org" , "netdev@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "git (AMD-Xilinx)" , "Katakam, Harini" References: <20250525102217.1181104-1-suraj.gupta2@amd.com> <679d6810-9e76-425c-9d4e-d4b372928cc3@linux.dev> <6c99b7f5-b529-4efd-a065-1e0ebf01468e@lunn.ch> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: <6c99b7f5-b529-4efd-a065-1e0ebf01468e@lunn.ch> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250529_093518_249468_2AEAC836 X-CRM114-Status: GOOD ( 11.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 5/29/25 12:29, Andrew Lunn wrote: >> Yeah, but the reason is that you are trading latency for throughput. >> There is only one queue, so when the interface is saturated you will not >> get good latency anyway (since latency-sensitive packets will get >> head-of-line blocked). But when activity is sparse you can good latency >> if there is no coalescing. So I think coalescing should only be used >> when there is a lot of traffic. Hence why I only adjusted the settings >> once I implemented DIM. I think you should be able to implement it by >> calling net_dim from axienet_dma_rx_cb, but it will not be as efficient >> without NAPI. >> >> Actually, if you are looking into improving performance, I think lack of >> NAPI is probably the biggest limitation with the dmaengine backend. > > It latency is the goal, especially for mixing high and low priority > traffic, having BQL implemented is also important. Does this driver > have that? > > Andrew Yes, see commit c900e49d58eb ("net: xilinx: axienet: Implement BQL"). --Sean