From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bmailout2.hostsharing.net (bmailout2.hostsharing.net [83.223.78.240]) (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 5B798185935 for ; Tue, 8 Apr 2025 15:28:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.223.78.240 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744126142; cv=none; b=WKXFYR/ncnhF/+nWIayRUocbIjnwFgwuiEGUSoR4nr3SeZV91IjGXcOlQ7xFS7Dlnbb2Dr5K1SAhg/J81PFumMOIol23ofZoa08flCUt6kdkFBTE9I/7nZJgCQMK5N02iKbRNC8zJpwnN0BZN+8NYzqQFVlV87WgL02cPAYZeLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744126142; c=relaxed/simple; bh=U2qUsxY/owniltXMFSi+vDO1f58AxkMTNvF/h/JTJgU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WXYUlWvMUg9rLdg4w303WxvoKqzm39OBZggAIIpNskneCVAEq6YZBmpdr1zhVjSFJPj1sTb9qrTtcAwJ3yLdlXDef9xf1LDM02XYPTxQqYLSNXxyoC5gB/d08vtJHzHhx+fHB7AZyX/00GRIrKEu0GGG6bTgl6weAQNjGrzr2rA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=none smtp.mailfrom=h08.hostsharing.net; arc=none smtp.client-ip=83.223.78.240 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=h08.hostsharing.net Received: from h08.hostsharing.net (h08.hostsharing.net [IPv6:2a01:37:1000::53df:5f1c:0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by bmailout2.hostsharing.net (Postfix) with ESMTPS id 46119200D253; Tue, 8 Apr 2025 17:28:34 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 0700F354AA; Tue, 8 Apr 2025 17:28:56 +0200 (CEST) Date: Tue, 8 Apr 2025 17:28:56 +0200 From: Lukas Wunner To: Damir Chanyshev Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, Logan Gunthorpe , "Michael J. Ruhl" , Ilpo =?iso-8859-1?Q?J=E4rvinen?= Subject: Re: P2PDMA support status for the sappire rapids+ Message-ID: References: <20250408150623.GA232275@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@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 Tue, Apr 08, 2025 at 06:14:55PM +0300, Damir Chanyshev wrote: > On Tue, Apr 8, 2025 at 6:06???PM Bjorn Helgaas wrote: > > The pci_p2pdma_whitelist[] is only updated when somebody tests a > > platform and determines that its RC can route peer-to-peer > > transactions between separate Root Ports. This routing is not > > required by the PCIe spec, so we can't assume that all platforms > > support it. > > For the testing, is simple rdma ping-pong sufficient? Or a more > specific testing tool? > Unfortunately I don't have a fancy pcie hardware analyzer. You should test that performance is satisfactory for you needs. There are claims that older Intel CPUs have poor p2pdma performance: https://lore.kernel.org/all/e2c56983-0111-4132-ae17-0095aa33fd2d@deltatee.com/ Thanks, Lukas