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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 697FFC54798 for ; Tue, 5 Mar 2024 13:11:41 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7F3B1112AB9; Tue, 5 Mar 2024 13:11:40 +0000 (UTC) X-Greylist: delayed 1012 seconds by postgrey-1.36 at gabe; Tue, 05 Mar 2024 13:11:39 UTC Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4464D112AB9 for ; Tue, 5 Mar 2024 13:11:39 +0000 (UTC) Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4TpwVc6CY4zbcjb; Tue, 5 Mar 2024 20:54:00 +0800 (CST) Received: from dggpemm500005.china.huawei.com (unknown [7.185.36.74]) by mail.maildlp.com (Postfix) with ESMTPS id D491214037C; Tue, 5 Mar 2024 20:54:42 +0800 (CST) Received: from [10.69.30.204] (10.69.30.204) by dggpemm500005.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Tue, 5 Mar 2024 20:54:42 +0800 Subject: Re: [RFC PATCH net-next v6 00/15] Device Memory TCP To: Mina Almasry , , , , , , , , , , , , , CC: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Richard Henderson , Ivan Kokshaysky , Matt Turner , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Andreas Larsson , Jesper Dangaard Brouer , Ilias Apalodimas , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , David Ahern , Willem de Bruijn , Shuah Khan , Sumit Semwal , =?UTF-8?Q?Christian_K=c3=b6nig?= , Pavel Begunkov , David Wei , Jason Gunthorpe , Shailend Chand , Harshitha Ramamurthy , Shakeel Butt , Jeroen de Borst , Praveen Kaligineedi References: <20240305020153.2787423-1-almasrymina@google.com> From: Yunsheng Lin Message-ID: <6208950d-6453-e797-7fc3-1dcf15b49dbe@huawei.com> Date: Tue, 5 Mar 2024 20:54:42 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20240305020153.2787423-1-almasrymina@google.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.69.30.204] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500005.china.huawei.com (7.185.36.74) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 2024/3/5 10:01, Mina Almasry wrote: ... > > Perf - page-pool benchmark: > --------------------------- > > bench_page_pool_simple.ko tests with and without these changes: > https://pastebin.com/raw/ncHDwAbn > > AFAIK the number that really matters in the perf tests is the > 'tasklet_page_pool01_fast_path Per elem'. This one measures at about 8 > cycles without the changes but there is some 1 cycle noise in some > results. > > With the patches this regresses to 9 cycles with the changes but there > is 1 cycle noise occasionally running this test repeatedly. > > Lastly I tried disable the static_branch_unlikely() in > netmem_is_net_iov() check. To my surprise disabling the > static_branch_unlikely() check reduces the fast path back to 8 cycles, > but the 1 cycle noise remains. > The last sentence seems to be suggesting the above 1 ns regresses is caused by the static_branch_unlikely() checking?