From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91C4B4C6E; Wed, 4 Dec 2024 00:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733273519; cv=none; b=CtZVnRv9ovia/cYjDsnDMnCQzUdtvaMohVF/v8+O97o3xjOpRA5cn82jk2mA5QCNchMPSwJuPuRImE7s9AS+wM1kVEJF4Oj0O4g+xZdT5J7LtBRUoZ/4FvAtcFcNS0cnz3DHeT4sJ7KK0lg9JF6HFsps2/DHE+hGDMxjM76rRu0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733273519; c=relaxed/simple; bh=couke5zqObDh6jfTvyi0RoSa3UQwJPldsoPVcoy3YNg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=F3xxKkFqxt3LHk4WiGDB/tyWCqVAQtdzvAXJ2ure3YCYXlnEBhIC5wspq1O6fBDRTmjo1X7CuxO2b1QItm9eDwYBlCBfFXkhhzRU4bh70kgWuZNZtZO0Huk5IJtvwvVz+QPEEqOwjeuPDV2dV7gf8qVaC2sr2fuFJOrVMW8Om8U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=h5FcLY/N; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="h5FcLY/N" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7689FC4CEDC; Wed, 4 Dec 2024 00:51:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733273519; bh=couke5zqObDh6jfTvyi0RoSa3UQwJPldsoPVcoy3YNg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=h5FcLY/NdEHm4JxdBMdSDwV3OOZPqzN1QrAQl82nEqJUPqTXu1AKhp+rvlEY6MnJO TqFMiJVfW9HwXw4xk9iJx7Cf/Eb2V/R8JZadrd2stYabeg2uENy0P2J0ikV/o0RVjJ 5ZK7X2RjTKRAVoR1ovqVBJWplkuU7gqDUHNyQO2zunBuaHz8SKXWighBactEEZJirT vjDgptqU8IE5QFsZqUA6n3u/6sM3TJC8QovauP5HHwbIBn78hfbmSIjPyJ2US2KopJ pFs0rx/ML5yEA51oxK6vhezgNI5lYlIMRCrgDvMTFZQinlq6aqA1Dx0yGq+LugOzD5 rgBDw0wM3Czkg== Date: Tue, 3 Dec 2024 16:51:57 -0800 From: Jakub Kicinski To: Alexander Lobakin Cc: Daniel Xu , Lorenzo Bianconi , Lorenzo Bianconi , "bpf@vger.kernel.org" , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , John Fastabend , Jesper Dangaard Brouer , "Martin KaFai Lau" , David Miller , "Eric Dumazet" , Paolo Abeni , Subject: Re: [RFC/RFT v2 0/3] Introduce GRO support to cpumap codebase Message-ID: <20241203165157.19a85915@kernel.org> In-Reply-To: <4f49d319-bd12-4e81-9516-afd1f1a1d345@intel.com> References: <55d2ac1c-0619-4b24-b8ab-6eb5f553c1dd@intel.com> <01dcfecc-ab8e-43b8-b20c-96cc476a826d@intel.com> <05991551-415c-49d0-8f14-f99cb84fc5cb@intel.com> <6db67537-6b7b-4700-9801-72b6640fc609@intel.com> <20241202144739.7314172d@kernel.org> <4f49d319-bd12-4e81-9516-afd1f1a1d345@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 3 Dec 2024 12:01:16 +0100 Alexander Lobakin wrote: > >> @ Jakub, > > > > Context? What doesn't work and why? > > My tests show the same perf as on Lorenzo's series, but I test with UDP > trafficgen. Daniel tests TCP and the results are much worse than with > Lorenzo's implementation. > I suspect this is related to that how NAPI performs flushes / decides > whether to repoll again or exit vs how kthread does that (even though I > also try to flush only every 64 frames or when the ring is empty). Or > maybe to that part of the kthread happens in process context outside any > softirq, while when using NAPI, the whole loop is inside RX softirq. > > Jesper said that he'd like to see cpumap still using own kthread, so > that its priority can be boosted separately from the backlog. That's why > we asked you whether it would be fine to have cpumap as threaded NAPI in > regards to all this :D Certainly not without a clear understanding what the problem with a kthread is.