From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 E3C96246788 for ; Wed, 19 Aug 2026 05:25:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787117125; cv=none; b=S4YJsf4sqKCRg4Xp8kPj035YLtCtcrBG3rD4jgwCRiwX2VUCeXNjvyUDxCuTjhkcSfT1wnzPl7x9zg5ET7b5TITdkJ4oipQ6THl3+PUU2+NFZ4DWPdblhYEA3ylCJepQF4SoAkQsXcWA5ZYM4kdDg+HtrwhfFFlpl/zbGSsag2Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787117125; c=relaxed/simple; bh=t8kKd2ay7Yp1BOrBBa3SNcuawXgwxixB1PsE8cj+AHw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nRmt4j1hPHUIMyoRmccQhjn6sIeVa7TpH28F6691ZpOs6C31mZ/HZ4h5+hLp7DfAn/RbdQkub9llqUKq5W5ApXPGeN7FFaBZ1GlnBfJQQQfQt/CHG6i5+HCkzec4iJTR3D6kzCEynE9SSr3LV/l72JgsAIlJ6C6QhJF5MVkOhSU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 1687E68C7B; Wed, 19 Aug 2026 07:25:18 +0200 (CEST) Date: Wed, 19 Aug 2026 07:25:17 +0200 From: Christoph Hellwig To: changfengnan Cc: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, jun1.zeng@intel.com, Guzebing Subject: Re: [PATCH] nvme-pci: add adaptive interrupt polling Message-ID: <20260819052517.GB32364@lst.de> References: <20260818033846.53790-1-changfengnan@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) On Tue, Aug 18, 2026 at 11:53:55AM +0800, changfengnan wrote: > 1. Regarding the NVME_ADAPTIVE_POLL_PERIOD_NS parameter, is it necessary to make it a configurable setting? Perhaps Gen6 SSDs require a smaller value? I currently do not have a testing environment for this, but the default value of 10 us appears to be sufficient for Gen4 and Gen5.  The most important thing to consider in the short term is not the fastest possible devices, but the worst. I.e. consider what this does on really crappy older cusomer drives, as that is probably the biggest install base using the Linux nvme driver. > 2. Should MSI be supported? I do not have a similar environment, so I am unsure how it would perform in such scenarios.  Or legacy interrupts :) I don't think we have to support them as long as we cleanly disable the feature. > 3. Should it be enabled by default? Although current tests show only a minor performance hit, I still lean toward disabling it by default and waiting to gather more test feedback. I think it should eventually enabled by default, but I'd also be happy to merge it fist and then flip the bit later.