From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A6ECD3B38AF for ; Tue, 7 Apr 2026 13:47:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775569671; cv=none; b=toUdxG5DqqCR+4PahOP+2P4Q2m4HuXNTig+VdIdwYxGXCn/5foSbdJ0Xv3eDgHFTuAYRa2a1xqTP0a5eiYUS5eWouvjKgqXY4x6CRNEO3btSnUwHKLXaiGA3EHnyCtMU7I2tN8o3R7GBcQlQgqCrRwXk3irzQUDM8eEeDGmPfBY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775569671; c=relaxed/simple; bh=YCxm5IsUZWkOVmsnnCElZfL8KDjU6K9uk5Pr3gZX1nc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mIjvkhKUe7XCEE0Z+5Nkp2lDvl68USy1XSyLI3Tl2wuWb0P8EjuKZT5Mk+BaxTwOigsS+LRdWLHEQeHFxuimp+t31nVBhWt9Toobicot7Qxz51kQr2I9MfxxOkUlzJ6udIj3tR+UNWAJMlUfS/XeSALNQEGZ4socHfYVxeCQgmQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=VVPYMBNy; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="VVPYMBNy" 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 44D8A16F2; Tue, 7 Apr 2026 06:47:43 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CEB003F7D8; Tue, 7 Apr 2026 06:47:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1775569669; bh=YCxm5IsUZWkOVmsnnCElZfL8KDjU6K9uk5Pr3gZX1nc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VVPYMBNyFaH6onWlNAwGCgXqVZGQkTcoMTSFGWNL93JMN3nv3BLkZePnFnacj6De6 jCgyNxQVNTeX+ACgzoSM21XwGim9Q6AvQrjUQfyJ5TKZm5oaT1z/rI/wZROF8uDTZy NzlrzHYBnkils0WuAfTTUSw1Dh9VbZRQ9Ut2ROTM= Date: Tue, 7 Apr 2026 14:47:45 +0100 From: Catalin Marinas To: Linus Walleij Cc: Will Deacon , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Subject: Re: [PATCH] arm64: clear_page[s] using memset Message-ID: References: <20260306-aarch64-clear-pages-c-v1-1-77c1bb0f1c21@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 07, 2026 at 11:25:55AM +0200, Linus Walleij wrote: > Quoting my own commit message hehe: > > > No performance regressions can be seen, the fastpath > > benchmarks differences are in the noise. > > This was tested on hardware with Ryan Robert's fastpath tool. BTW, have you tried the perf bench mmap test again with the new clear_page? Both with single page and multiple pages scenarios. And ideally on more than one platform. Will pointed out (in a private chat) that current clear_page() uses non-temporal stores while memset() doesn't. It may not make any difference in practice but it would be good to have some numbers. -- Catalin