From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75A0DC47080 for ; Tue, 1 Jun 2021 10:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58A376139A for ; Tue, 1 Jun 2021 10:25:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233695AbhFAK07 (ORCPT ); Tue, 1 Jun 2021 06:26:59 -0400 Received: from foss.arm.com ([217.140.110.172]:46430 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233641AbhFAK0s (ORCPT ); Tue, 1 Jun 2021 06:26:48 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5677711FB; Tue, 1 Jun 2021 03:25:07 -0700 (PDT) Received: from e113632-lin (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6A81A3F73D; Tue, 1 Jun 2021 03:25:06 -0700 (PDT) From: Valentin Schneider To: Marc Zyngier Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Thomas Gleixner , Lorenzo Pieralisi , Vincenzo Frascino Subject: Re: [RFC PATCH v2 00/10] irqchip/irq-gic: Optimize masking by leveraging EOImode=1 In-Reply-To: <87zgwgs9x0.wl-maz@kernel.org> References: <20210525173255.620606-1-valentin.schneider@arm.com> <87zgwgs9x0.wl-maz@kernel.org> Date: Tue, 01 Jun 2021 11:25:01 +0100 Message-ID: <87tumhg9vm.mognet@arm.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/05/21 12:17, Marc Zyngier wrote: > On Tue, 25 May 2021 18:32:45 +0100, > Valentin Schneider wrote: >> I've tested this on my Ampere eMAG, which uncovered "fun" interactions with >> the MSI domains. Did the same trick as the Juno with the pl011. >> >> pNMIs cause said eMAG to freeze, but that's true even without my patches. I >> did try them out under QEMU+KVM and that looked fine, although that means I >> only got to test EOImode=0. I'll try to dig into this when I get some more >> cycles. > > That's interesting/worrying. As far as I remember, this machine uses > GIC500, which is a well known quantity. If pNMIs are causing issues, > that'd probably be a CPU interface problem. Can you elaborate on how > you tried to test that part? Just using the below benchmark? > Not even that, it would hang somewhere at boot. Julien suggested offline that it might be a problem with the secondaries' PMR initial value, but I really never got to do dig into it. >> >> Performance impact >> ================== >> >> Benchmark >> +++++++++ >> >> Finding a benchmark that leverages a force-threaded IRQ has proved to be >> somewhat of a pain, so I crafted my own. It's a bit daft, but so are most >> benchmarks (though this one might win a prize). > > I love it (and wrote similar hacks in my time)! :D Yay! > Can you put that up > somewhere so that I can run the same test on my own zoo and find out > how it fares? > The setup part is really fugly and I was too ashamed of it to link it in the cover letter; for ACPI I could simply use acpi_register_gsi() since that uses the right domain by default, but for DT I ended up adding a DT entry and a match table. I'll see about unifying this and I'll send it out your way.