From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 82A1C40DFC2; Mon, 30 Mar 2026 16:11:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774887070; cv=none; b=aBB59iuYmY8Lq1Fq2S/FRA7IcTbqR1UAjoj9SkpnBEY4GgxFT4B1fE8ypxTg1BiViCPZbxgGaspwjYmBWSultxEDNgZUS4BJARqC9ei3LbB7iXxqgnrtSSSJMgp4p3K/hjc01y3V5ANRgxtSvfa8qL/Kk2uKkVmBPprf+1ur3ZY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774887070; c=relaxed/simple; bh=oJZrTPyIRvOFXqPNud3LjOv7VsxDT9058WiuK6PlqMc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ObfDW7eX4v5/2BNN8B8fTB/dIXDDiM5aGXRM4dVpeaMmx5x5UrUjex9RJy8NAakAuDDpGFOrdd5WjOHjUV04dRMjRronqv3JuwThdnKoj9VpDTQ5GddnaPG1WAUTp6Pi8mH4x6fcsdnHjowgkAp/Pgopnw1i0gsH0pqIcRr9fUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=g8EoFdtS; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="g8EoFdtS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1774887069; x=1806423069; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=oJZrTPyIRvOFXqPNud3LjOv7VsxDT9058WiuK6PlqMc=; b=g8EoFdtSrkc2lf0VsKoo5IyNvqhPnn3m4deXNfDmz2K2rtrewlshixto mDzWQtQqiBmVdlreme+EFDrL55ysV7Y7enFUo7kaO5EBzJBtD7b/6ZQOL Ely5QlH0AAkfGXmUO7FI5sIXeEW+WXb6ygYjJopHs8wwN1gSVTedEW0+k izxhNw9CUNv57WjZtSBAuVA1klPCXM8W/eueuxpWLT39Nm89CdWiG4LNP ABAuwUyfGwWn8qRUHIxoTKLHiVqwFxVi+a81mggE5xJwWbXevayyykee4 He8vXvwB/z1Q4DFqNHagAea9UUak3yDEl41/VzhSZMEf0TiqiRRuwKzvT g==; X-CSE-ConnectionGUID: 3DT7oglHTRiCIR827smxVw== X-CSE-MsgGUID: 1poIhZzPSsqK+miPkXojXA== X-IronPort-AV: E=McAfee;i="6800,10657,11743"; a="98495918" X-IronPort-AV: E=Sophos;i="6.23,150,1770624000"; d="scan'208";a="98495918" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2026 09:11:08 -0700 X-CSE-ConnectionGUID: VjfuB/m5RQGKMHXVvw3MXg== X-CSE-MsgGUID: kJhyq0RwQ2q99LagssHCYA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,150,1770624000"; d="scan'208";a="249148231" Received: from guptapa-desk.jf.intel.com (HELO desk) ([10.165.239.46]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2026 09:11:06 -0700 Date: Mon, 30 Mar 2026 09:11:00 -0700 From: Pawan Gupta To: Jon Kohler Cc: "x86@kernel.org" , Nikolay Borisov , "H. Peter Anvin" , Josh Poimboeuf , David Kaplan , Sean Christopherson , Borislav Petkov , Dave Hansen , Peter Zijlstra , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , KP Singh , Jiri Olsa , "David S. Miller" , David Laight , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , David Ahern , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , Stanislav Fomichev , Hao Luo , Paolo Bonzini , Jonathan Corbet , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , Asit Mallick , Tao Zhang , "bpf@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-doc@vger.kernel.org" Subject: Re: [PATCH v8 00/10] VMSCAPE optimization for BHI variant Message-ID: <20260330161100.conyluyigj322gb3@desk> References: <20260324-vmscape-bhb-v8-0-68bb524b3ab9@linux.intel.com> <3B7BF368-4A3A-4853-A7CD-6F17E7982546@nutanix.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3B7BF368-4A3A-4853-A7CD-6F17E7982546@nutanix.com> On Mon, Mar 30, 2026 at 03:16:32AM +0000, Jon Kohler wrote: > Tested the v7 of this series with 6.18.y and one of our performance > suites, where we had previously bisected a significant regression to > the enablement of the VMSCAPE mitigation. This particular suite looks > at synthetic performance using KVM virtualized Windows guests. > > Long story short, this suite tries to derive what end user experience > would be in these virtual machines while performing a standardized set > of synthetic tasks on real apps. > > VMSCAPE hits especially hard when enabling Windows HVCI, which drives > a much higher VMExit count, all else equals. > > Tested on an Intel Xeon 6444Y (SPR) > > TLDR, we're really happy with the results. The following was with > Intel MBEC *enabled*, so even with that speedup (and drastic reduction > in VMExits), this optimization makes a significant difference. > > - CPU‑ready time drops ~70 % across all steady‑state and log‑on metrics > with this series, indicating more efficient context switching even > though overall hypervisor CPU rises ~14 % (steady) to ~12 % (max). > Basically, we're getting more actual work done. > - Read/write IOPS increase by ~18–37 % and 14–20 % respectively, while > average IO latency remains largely unchanged or slightly lower in > steady metrics. > - Power consumption falls 5–11 % in every category > - Login times improve by 4–6 % on average. > - Application start‑up times are generally better (Word, Excel, > PowerPoint, Outlook), especially Outlook max time drops 67 %, a clear > win for end‑user experience. These results are promising. > Tested-By: Jon Kohler Thanks for testing, Jon.