From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 1EA551779AE; Thu, 17 Oct 2024 06:19:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729145963; cv=none; b=kUziK+NBRbFRrpSX/Fx+NKWbJoaZFk5Q9Ra/MNu8ocafnAY5QZS6y+d7/rXiZYcX+JN5ZRuSqTAhRYVfofsz3DTLqXPrHz21MBw39Gp3rMKMisgcnbnpHbfUzujwnPn8mnuOCd1759etJXWcdFVIHMzpSDRK2S8SVvJo1IMmDP0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729145963; c=relaxed/simple; bh=dLlQ+uvki9JZnWSM4ozKPNHPAtPTrRMYxxs2H3DkD5o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RZ2QqnhTVTIis6MIXpuVt1LZyl0QxREFs2F3MHfWn0w0Z4P3RouRC6iHEX3l1EC33hOw8SMQYFGQvfngmhNVspjqXqlpJC3UQpZXnHFbyEbo8ml3Tckrf2HTMTlD47ANEFOVDv277EI5PwcLLKKxzLeC1DFKqomZGvhLS/Zmw8A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=rMsw78LN; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="rMsw78LN" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=UmMwy4PArAU+1RMHo1HvKaM7MT5SR9w1d9MHHi8WJlo=; b=rMsw78LNS35MQnEBuk4ouEIqtn /60SRp0kpOlIgjyUZkQN3bdAuCgj7DPTh1qRH65/r1+6ywHTEe0oxqkOZDmg8C5u+D57mEtqCjMLc 1nmER35UGjgU4loVw20Mx8567pUZ1DxaRSYNup4tUJfhPCbtLNG5NUW/xUmChCPtLqVqz04+Kpr1q QCf0ipKTmq4OjfkP4+DSKQWfiWY9KHzFMRhVNl4CtxN+UJXoMZ2n9c3rNjOFU4rTETUe8MWOqvyiw D4Y2jiW0lcVB9TCqP62Htxq998Z4pKYs9Gr6aYJQZg7RCNqROuMcDfZYV6L9krFp3exMifEFQmc5R N1fgPz0Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1t1Jqy-0000000DrGZ-14zc; Thu, 17 Oct 2024 06:19:20 +0000 Date: Wed, 16 Oct 2024 23:19:20 -0700 From: Christoph Hellwig To: Srujana Challa Cc: Christoph Hellwig , "virtualization@lists.linux.dev" , "kvm@vger.kernel.org" , "mst@redhat.com" , "jasowang@redhat.com" , "eperezma@redhat.com" , Nithin Kumar Dabilpuram , Jerin Jacob Subject: Re: [EXTERNAL] Re: [PATCH v2 0/2] vhost-vdpa: Add support for NO-IOMMU mode Message-ID: References: <20240920140530.775307-1-schalla@marvell.com> Precedence: bulk X-Mailing-List: kvm@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Oct 16, 2024 at 05:28:27PM +0000, Srujana Challa wrote: > When using the DPDK virtio user PMD, we’ve noticed a significant 70% > performance improvement when IOMMU is disabled on specific low-end > x86 machines. This performance improvement can be particularly > advantageous for embedded platforms where applications operate in > controlled environments. Therefore, we believe supporting the intel_iommu=off > mode is beneficial. While making the system completely unsafe to use. Maybe you should fix your stack to use the iommu more itelligently instead?