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[209.85.208.180]) by smtp.gmail.com with ESMTPSA id s22sm1791142ljm.41.2020.01.29.15.49.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Jan 2020 15:49:25 -0800 (PST) Received: by mail-lj1-f180.google.com with SMTP id h23so1302388ljc.8 for ; Wed, 29 Jan 2020 15:49:25 -0800 (PST) X-Received: by 2002:a2e:85ce:: with SMTP id h14mr988980ljj.41.1580341764990; Wed, 29 Jan 2020 15:49:24 -0800 (PST) MIME-Version: 1.0 References: <20200117162444.v2.1.I9c7e72144ef639cc135ea33ef332852a6b33730f@changeid> <87y2tytv5i.fsf@nanos.tec.linutronix.de> <87eevqkpgn.fsf@nanos.tec.linutronix.de> <87d0b82a9o.fsf@nanos.tec.linutronix.de> <878slwmpu9.fsf@nanos.tec.linutronix.de> <87imkv63yf.fsf@nanos.tec.linutronix.de> <87pnf342pr.fsf@nanos.tec.linutronix.de> <877e1a2d11.fsf@nanos.tec.linutronix.de> <874kwd3lbn.fsf@nanos.tec.linutronix.de> In-Reply-To: <874kwd3lbn.fsf@nanos.tec.linutronix.de> From: Evan Green Date: Wed, 29 Jan 2020 15:48:48 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] PCI/MSI: Avoid torn updates to MSI pairs To: Thomas Gleixner Cc: Rajat Jain , Bjorn Helgaas , linux-pci , Linux Kernel Mailing List , x86@kernel.org, Marc Zyngier Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 29, 2020 at 3:16 PM Thomas Gleixner wrote: > > Evan, > > Evan Green writes: > > On Wed, Jan 29, 2020 at 1:01 PM Thomas Gleixner wrote: > > > >> Could you please add some instrumentation to see how often this stuff > >> actually triggers spurious interrupts? > > > > In about 10 minutes of this script running, I got 142 hits. My script > > can toggle the HT cpus on and off about twice per second. > > Here's my diff (sorry it's mangled by gmail). If you're looking for > > something else, let me know, or I can run a patch. > > > No, that's good data. Your testing is hiting the critical path and as > you did not complain about negative side effects it seems to hold up to > the expectations. I'm going to convert this to real patch with a > proper changelog tomorrow. > > Thanks for your help! Sounds good, please CC me on it and I'll be sure to test the final result as well. -Evan