From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 040A8381AF for ; Fri, 14 Aug 2026 22:16:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786745797; cv=none; b=S/vgkTS+4z35k/1ECH+v3vvOkROftF/srgoH2G2fs4bAKmtOyVKPBzDFOORMekpYLV5N3TrImvuJWgWFh/+Zo0tt8g0fzuAnzlU275Xt+1bxk1m0RnAx2RKRuAWCscPzss1p3RzwTyNfqIa6g1Xc+axJShbseyI1BcPDjiB7OSE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786745797; c=relaxed/simple; bh=IvC6dlT8m/80mnZnOIVzDEdas22n/o3VdoXqQRRl/O0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pe7/Ho9IamirhtXu1xq22CzqeHZfkpsjszN+NZTsEMRY7nLuSX7Gk7yuMtg6XUxyP9M/3NlWDhQkY472vVkcVhxl2V37Yn2/1kVPShggQ4Ji7fbipyS1qG1HXV60Bjz3/TpnFiIwJB/BIk5qAZiA7pb6sV9CR+W9ZzzgEXaq1mw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=af8HbGgt; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="af8HbGgt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51E8C1F000E9; Fri, 14 Aug 2026 22:16:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786745795; bh=jsU+x82WmlajkDCJyuwvAb1ngGFbDbQuk3q0k9VNyK8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=af8HbGgthUZ+fERKOMj72iKEQoh04Cs4ok0rdxM7e7rQ4qbi4xCicToTQwNONSf3F 6HvxA5Rt/5kF8+zh9L7DRYe/v1PfYhVZn1ofXvaDF8SwXXurFMWmKaPPutSBmAhan8 SB41xegzOG5PGGn9WqJna1lVBeOv7+xt2l5RF8jSoOU/LFJguWQDZFZ6krDL6yopZW 0hSLCuZgkU3ON9GMXokQDqzX4AkvgAEXW57aM8FwJBP3CtmlzR2ITxm8kbC2NE9bsU TQRAYYA2Wmt7imHRbZM7rvmuu9/ikH+mG4NSQWttYzTaRwzAeJGJzLaMOdRjF5dzIa 0TMGOg28SwO1g== Date: Fri, 14 Aug 2026 16:16:33 -0600 From: Keith Busch To: Anuj Gupta Cc: changfengnan , axboe@kernel.dk, hch@lst.de, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Guzebing , anuj20.g@samsung.com Subject: Re: [RESEND RFC PATCH v2] nvme-pci: add adaptive interrupt polling Message-ID: References: <20260806031058.40176-1-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=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Aug 13, 2026 at 09:15:31AM +0530, Anuj Gupta wrote: > > I also had a similar assesment on DIM. Emperically, with Keith's POC > interrupts per IO drop from ~1.0 to ~0.29 but with a small performance > regression (572K -> 557K IOPS). With your original approach they drop to > ~0.03 with a 23% performance gain. The DIM machinery overhead maybe > outweighing the partial interrupt reduction. I may ultimately adandon this suggestion, but it looks like a major factor in performance loss was from using IRQ_WAKE_THREAD with sleep cycles instead of the softirq hrtimer. Just changing that is getting me back to performance parity, but since it's not any better, perhaps the hill climb is a worse algorithm than trying to reason out the delayed poll time directly.