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 6268FA923 for ; Sun, 10 Nov 2024 13:31:33 +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=1731245493; cv=none; b=AWsOcXb7cF9afOEyB7XzfChqLvZUf3Za7rUcdMmkUgbBlt97pPaIOrtNpNLkd2rlmz9MTSyHdah0KsPm/VviBPr8jqSsjc2/11KMJW7RKPKzM7ad3PleUxBNx5ZVbAtYU1rd1oCMx1gx4PYplHHbBUpQni0c3kJJD+2+pMvuJW0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731245493; c=relaxed/simple; bh=FSCxufNudrh5zvvWlyq8abL6PtbPvmEcrE8gDPLYNCU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SseZPt6bKmJPmVPwx11pDFdFA+7Tmsnqk87IHLEfuqra+Yj1pYtRZJffLE/t4Vvmmk/90tdvOTVAsyeXDVNl7ZLUfY4cqFzpkaXjfBtlgVeHjP9K3L4yFlEarxrnLAgsZLFosUQHo6F0u0wWjTiKhNx8W95K746JDU5zox5z7CE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Fxp97AWE; 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="Fxp97AWE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B053DC4CECD; Sun, 10 Nov 2024 13:31:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731245492; bh=FSCxufNudrh5zvvWlyq8abL6PtbPvmEcrE8gDPLYNCU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Fxp97AWEZCop7n8Hvcnp3ty1Rd8yty+jXVCVzH18z86IKFyig/Q7xWtCgLu8hi3KU j31122NmTj2l86eNIz/7QEPKwxjKm1CucNAMRv+p8xK4h4Z0ZygvwBGRF9XhDHYOW+ 1D8I40RQY8hGnKVO3kr6RnXWWfmDRjRjeCo77chLdirsb/TbFUHWidFGeFf7pxggyT xqVK4Ib1gI0BVq1gG+idGuZTOFdNFn8biKxT3M14KQtgE2RCUN33R6j71hfwMMcLw8 n6bHZZy+LSQSGGFiP4+KTL0R58btGTgaboc5HOnNLW5Azn0li1fewX9CR2GsURKnYD XqqDGnmxg9nOw== Date: Sun, 10 Nov 2024 13:31:28 +0000 From: Simon Horman To: Mohammad Heib Cc: netdev@vger.kernel.org, oss-drivers@corigine.com, louis.peens@corigine.com Subject: Re: [PATCH net] nfp: use irq_update_affinity_hint() Message-ID: <20241110133128.GM4507@kernel.org> References: <20241107115002.413358-1-mheib@redhat.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-Disposition: inline In-Reply-To: <20241107115002.413358-1-mheib@redhat.com> On Thu, Nov 07, 2024 at 01:50:02PM +0200, Mohammad Heib wrote: > irq_set_affinity_hint() is deprecated, Use irq_update_affinity_hint() > instead. This removes the side-effect of actually applying the affinity. > > The driver does not really need to worry about spreading its IRQs across > CPUs. The core code already takes care of that. when the driver applies the > affinities by itself, it breaks the users' expectations: > > 1. The user configures irqbalance with IRQBALANCE_BANNED_CPULIST in > order to prevent IRQs from being moved to certain CPUs that run a > real-time workload. > > 2. nfp device reopening will resets the affinity > in nfp_net_netdev_open(). > > 3. nfp has no idea about irqbalance's config, so it may move an IRQ to > a banned CPU. The real-time workload suffers unacceptable latency. > > Signed-off-by: Mohammad Heib Reviewed-by: Simon Horman