From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 166473FBEBC; Thu, 11 Jun 2026 13:45:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781185509; cv=none; b=UxdEoKvV+APV+VffqgSggF2jwAJXfAuHDb8nVfT/zfyYGswq5Mu/80DVcvjaPrB+458w2KC6PJMfwingSX0eebME9RyLJIZ1ro7qAnlCV3GUKtWKTQLz3c4rUsbau2ENXiOC08IvkkB4B13gmY8jVmrlw3veeuwG4Y4gla9GPy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781185509; c=relaxed/simple; bh=kUIwqYLzboTXSW9mocUnEjpqnAKtc9Q3KI2UV2OLx0Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=l5DWruKl6rGFWLqoSTUu5V984+xtht/7FiC2XTs5LiBCq14bENWnu7/VWepVS+myI6vBr1/6l+0AbNt0+k9QghSMK474oc2O+UXjpIqIz10rJpjfgRg8nqtrQORcNBm9mx7Q5SEzt994vKhaKyzihaswMEHV+DYZdS8b5ODXI8I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ibs/lTWy; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ibs/lTWy" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=m0fD9KCk/6I6qo6Wg6wfui77ADSGp/LJkYfEAup3lwY=; b=ibs/lTWyAjLVWXS3n4wPjA79OS ITb//Iv1CxtQUrx/67IL+hYSamUfqJOQPft+Dglj3UFpe6AehWYKHnyrdmyQlnLCCHnR37eSF04YY BV8xlmAh95887QUefrFHmh4w0rqaGST435zBbQpMYZ8US3gRQg+HjRI0XuAaxBi7gclydQf69ZDM5 k61d3A3iRRXuQJHaZacf+KNxVaTzU7pWHtqGjdFKnziZBtLLfi6vKmz1i2qN9G7/mZEKcluKIADZP arbxTyUtAa9KswEQnkGYCnK7u+EJaXbbI3n2nupMq3G+mbNR2VmbwbcZlBXNHkE7grhJz1GNpvuDh FnJVAQdw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXfi7-00000001ydR-0GUg; Thu, 11 Jun 2026 13:44:43 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 0B6CD3002F0; Thu, 11 Jun 2026 15:44:42 +0200 (CEST) Date: Thu, 11 Jun 2026 15:44:42 +0200 From: Peter Zijlstra To: Dmitry Ilvokhin Cc: Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Thomas Bogendoerfer , Juergen Gross , Ajay Kaher , Alexey Makhalov , Broadcom internal kernel review list , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Dennis Zhou , Tejun Heo , Christoph Lameter , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, virtualization@lists.linux.dev, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, kernel-team@meta.com, "Paul E. McKenney" Subject: Re: [PATCH v6 5/7] locking: Add contended_release tracepoint to qspinlock Message-ID: <20260611134442.GJ48970@noisy.programming.kicks-ass.net> References: <5d7ea75ffe74a785e6b234ada9f23c6373d4b4c1.1777999826.git.d@ilvokhin.com> <20260513193342.GB2545104@noisy.programming.kicks-ass.net> <20260603120811.GW3493090@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-trace-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, Jun 11, 2026 at 07:17:41AM +0000, Dmitry Ilvokhin wrote: > On Wed, Jun 03, 2026 at 02:08:11PM +0200, Peter Zijlstra wrote: > > Also, I think someone should go do some performance runs with > > ARCH_INLINE_SPIN_* set for x86 just like for s390. > > As promised, I set ARCH_INLINE_SPIN_UNLOCK{,_BH,_IRQ,_IRQRESTORE} for > x86 and measured the effect on a few real workloads. > > Short version: inlining of _raw_spin_unlock() adds measurable kernel > i-cache pressure on every workload I tried, and on a > kernel-i-cache-bound one (nginx connection churn) it costs ~1.27% > throughput. I did not find a workload where it helps. Thanks for checking!