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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6FA18C433DF for ; Wed, 27 May 2020 07:48:34 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 02395208B8 for ; Wed, 27 May 2020 07:48:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pni6+ov8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02395208B8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 9A1FE4B159; Wed, 27 May 2020 03:48:33 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id j8ujQQntyqvn; Wed, 27 May 2020 03:48:32 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 6FA324B193; Wed, 27 May 2020 03:48:32 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 8CF2F4B172 for ; Wed, 27 May 2020 03:48:31 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id S69ksfA47aJp for ; Wed, 27 May 2020 03:48:30 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 727D24B159 for ; Wed, 27 May 2020 03:48:30 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 23590207CB; Wed, 27 May 2020 07:48:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590565709; bh=o2RNuuLOPzIUQugqXI2pXs40dw3MxypX2JaA7iDkwY8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pni6+ov8tRzZ5DYViPK8gJK1/JIpPkaSWj18F4PfL9wWknwOagXXMykJH5HcwlvDQ x3IiBKDcFTUwwSCMybSkdY/4dptm9ehSXmDPIAHI+/XDgYY1Knn4OLNEjNFyJBSJnJ 20ZlhzylGziKft32Jn5ApIezyaR0yfrkfHQwD5Sw= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jdqnb-00FdJT-Gw; Wed, 27 May 2020 08:48:27 +0100 MIME-Version: 1.0 Date: Wed, 27 May 2020 08:48:27 +0100 From: Marc Zyngier To: Gavin Shan Subject: Re: [PATCH RFCv2 0/9] kvm/arm64: Support Async Page Fault In-Reply-To: <987785b2-2533-c3d8-8f6a-4193aa82d502@redhat.com> References: <20200508032919.52147-1-gshan@redhat.com> <20200526130927.GH1363@C02TD0UTHF1T.local> <987785b2-2533-c3d8-8f6a-4193aa82d502@redhat.com> User-Agent: Roundcube Webmail/1.4.4 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: gshan@redhat.com, mark.rutland@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, will@kernel.org, catalin.marinas@arm.com, james.morse@arm.com, suzuki.poulose@arm.com, drjones@redhat.com, eric.auger@redhat.com, aarcange@redhat.com, shan.gavin@gmail.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: catalin.marinas@arm.com, linux-kernel@vger.kernel.org, shan.gavin@gmail.com, pbonzini@redhat.com, will@kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On 2020-05-27 03:39, Gavin Shan wrote: > Hi Mark, [...] >> Can you run tests with a real workload? For example, a kernel build >> inside the VM? >> > > Yeah, I agree it's far from a realistic workload. However, it's the > test case > which was suggested when async page fault was proposed from day one, > according > to the following document. On the page#34, you can see the benchmark, > which is > similar to what we're doing. > > https://www.linux-kvm.org/images/a/ac/2010-forum-Async-page-faults.pdf My own question is whether this even makes any sense 10 years later. The HW has massively changed, and this adds a whole lot of complexity to both the hypervisor and the guest. It also plays very ugly games with the exception model, which doesn't give me the warm fuzzy feeling that it's going to be great. > Ok. I will test with the workload to build kernel or another better one > to > represent the case. Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm