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 060F4468BF; Tue, 10 Jun 2025 09:57:08 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 7F627402D4; Tue, 10 Jun 2025 09:57:08 +0200 (CEST) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by mails.dpdk.org (Postfix) with ESMTP id DF2FB40299 for ; Tue, 10 Jun 2025 09:57:06 +0200 (CEST) Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4bGgxv3bFJzRjcn; Tue, 10 Jun 2025 15:52:51 +0800 (CST) Received: from kwepemk500009.china.huawei.com (unknown [7.202.194.94]) by mail.maildlp.com (Postfix) with ESMTPS id 3921D180450; Tue, 10 Jun 2025 15:57:04 +0800 (CST) Received: from [10.67.121.161] (10.67.121.161) by kwepemk500009.china.huawei.com (7.202.194.94) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 10 Jun 2025 15:57:03 +0800 Message-ID: <7355246d-a914-48b6-acf6-4f67b3a9760b@huawei.com> Date: Tue, 10 Jun 2025 15:57:03 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] examples/l3fwd: adjust Tx burst size based on Rx burst To: huangdengdui , Stephen Hemminger , Sivaprasad Tummala CC: , , , , , , , , , , Venkat Kumar Ande References: <20250212045416.2393001-1-sivaprasad.tummala@amd.com> <20250609095827.4174387-1-sivaprasad.tummala@amd.com> <20250609082154.489681e1@hermes.local> <55beecec-89f9-43df-8eec-9e51bd72ed1c@huawei.com> Content-Language: en-US From: fengchengwen In-Reply-To: <55beecec-89f9-43df-8eec-9e51bd72ed1c@huawei.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.121.161] X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To kwepemk500009.china.huawei.com (7.202.194.94) 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 2025/6/10 14:42, huangdengdui wrote: > > On 2025/6/9 23:21, Stephen Hemminger wrote: >> On Mon, 9 Jun 2025 09:58:27 +0000 >> Sivaprasad Tummala wrote: >> >>> Previously, the TX burst size was fixed at 256, leading to performance >>> degradation in certain scenarios. >>> >>> This patch introduces logic to set the TX burst size to match the >>> configured RX burst size (--burst option, default 32, max 512) >>> for better efficiency. >>> >>> Fixes: d5c4897ecfb2 ("examples/l3fwd: add option to set Rx burst size") >>> Cc: haijie1@huawei.com >>> Cc: stable@dpdk.org >>> >>> Signed-off-by: Sivaprasad Tummala >>> Tested-by: Venkat Kumar Ande >>> Tested-by: Dengdui Huang >> >> What driver? Why not fix the driver. >> If RX burst is small, there should be no way to get TX burst larger >> than that to happen. > > If the Tx burst is too large, a number of mbufs will be temporarily stored in l3fwd's mbuf_table in a short period of time. > This leads to a decrease in the hit rate of the mempool cache, resulting in a drop in performance. This commit introduce coupling in Tx burst size and Rx burst size. Different arch may have differ combination for Rx/Tx burst and descriptors. So how about add one extra option for Tx burst size, and default the same with MAX_PKT_BURST. >