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 1DA981CEAC2; Tue, 10 Feb 2026 08:50:02 +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=1770713403; cv=none; b=kmIhVWULlqfuXrnXF+0o72YyPs42Cl6urrWoxwxSDr10l1lqWx6U6VC1OeE8C5PW08dMgCom9U98WUdN0fwBFl34K2lT0J1k62lxoWNKasYgQc3rZJJh8IJyyBcuZcI6apVKaZwKLACR/ObzyYdhC9xWzgy4lcWVUOdoW2LJc/E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770713403; c=relaxed/simple; bh=Si2j2OamdKyuLhvOjLLri8raYiy2rhxS+VNLI8ItD0E=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=lj6Nq9MNOcFWpIgablmAlN5Xx20eFuackNY1zXPuyg8IhqqxPQncCbBX2MKFtEz3FEh+rDK73H2+y0BiM+4Xe62R+1kbuE77699rhri4dG+f4vC8T6fDfYkGX1Xf/m0sIqZHB+Icu3cOfbwVNpQxVSeSU6W9m8kgpwYCgjmhdL8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YULiDm7y; 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="YULiDm7y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93512C116C6; Tue, 10 Feb 2026 08:50:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770713402; bh=Si2j2OamdKyuLhvOjLLri8raYiy2rhxS+VNLI8ItD0E=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=YULiDm7y4e6NWsk69SA37Ym2P/kMkdwfXgqOKL/WfmPH2grAXUuICIzya//ACFRil SBDa9yZisRh7dwXFBh6KMkGZMzlS6g0DzaCt2tEWUqhzOAhWY6lS6t8ktjTshUQEsN KLlyoDD7Cq96kMv8nIeEtyR4P8F2hEi9JWz0VqTvDGEPnwu7pc+2FJkH9a30hxGqar 51VFK/Ms1JJFNG2BoQzOjRUazH5UOuBurIQPiwmJUogXYJ3+ARRZ7X00ELjPt8KG3/ nsiughIMp2/0Y8EjI6eAt0wb/XYm3jTTt9IAprnZ0mTM0Kl27YJi6TYrg9Vk2QR0kd r/MfTJ9KLLJXg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vpjRX-00000009zjd-3spB; Tue, 10 Feb 2026 08:50:00 +0000 Date: Tue, 10 Feb 2026 08:49:59 +0000 Message-ID: <86v7g5asp4.wl-maz@kernel.org> From: Marc Zyngier To: Colton Lewis Cc: kvm@vger.kernel.org, Alexandru Elisei , Paolo Bonzini , Jonathan Corbet , Russell King , Catalin Marinas , Will Deacon , Oliver Upton , Mingwei Zhang , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Mark Rutland , Shuah Khan , Ganapatrao Kulkarni , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-perf-users@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v6 00/19] ARM64 PMU Partitioning In-Reply-To: <20260209221414.2169465-1-coltonlewis@google.com> References: <20260209221414.2169465-1-coltonlewis@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: coltonlewis@google.com, kvm@vger.kernel.org, alexandru.elisei@arm.com, pbonzini@redhat.com, corbet@lwn.net, linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, mizhang@google.com, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mark.rutland@arm.com, shuah@kernel.org, gankulkarni@os.amperecomputing.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-perf-users@vger.kernel.org, linux-kselftest@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 09 Feb 2026 22:13:55 +0000, Colton Lewis wrote: > > This series creates a new PMU scheme on ARM, a partitioned PMU that > allows reserving a subset of counters for more direct guest access, > significantly reducing overhead. More details, including performance > benchmarks, can be read in the v1 cover letter linked below. > > An overview of what this series accomplishes was presented at KVM > Forum 2025. Slides [1] and video [2] are linked below. > > IMPORTANT: This iteration does not yet implement the dynamic counter > reservation approach suggested by Will Deacon in January [3]. I am > working on it, but wanted to send this version first to keep momentum > going and ensure I've addressed all issues besides that. [...] As I have asked before, this is missing an example of how userspace is going to use this. Without it, it is impossible to correctly review this series. Please consider this as a blocker. Thanks, M. -- Without deviation from the norm, progress is not possible.