From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7D0991822CC for ; Wed, 17 Jul 2024 16:45:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721234703; cv=none; b=uMT2NFWHZDvjKl9mjz9Esm7NFJRvhKNSXemQPmDEKmMf0vg39DgopGn4HXwf+samhE4YgTUG23fbySr4x7EtppS7nnNU1EERy5u4opRXTRq/vvB6b02c5DifVxzj9JWuW77i51uJsjAWTVPH+kaYkr8G/xijk4tBOvDj7DxFBOA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721234703; c=relaxed/simple; bh=Fn+Lq6P6efRTL/3K52MnTwwZ9y10ySH+LiLX/lxr51g=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=I2/kGGdFnPvr9dJ1mFsOu5yNYjLvvQp+HSIovoVZ+2yIigIOTQsOLgzRDOGQ7kZ36i5jlR6vs4ax73KjVwf8B/58VMRezxqOmTcYAc+IxW5/hzcda73Beedp98sjDUDCGklZXalmhqqWYwvQZcJvrjZwDPJJiCoWyVzs/rPM0Is= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RLJvnS8J; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RLJvnS8J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2592FC2BD10; Wed, 17 Jul 2024 16:45:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1721234702; bh=Fn+Lq6P6efRTL/3K52MnTwwZ9y10ySH+LiLX/lxr51g=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RLJvnS8J1wPv1pEU+ddx/R3YGGXIBqPRDRMCsHKz3c9gnN++R+fX8k8fM25YyDg04 8jjcRl+zqiYDk/exFyQep3ribANNL73YUEOHaTXGq61aXVqH3WN9aOqrCVpn3l05On SU/dVV+eAjKElcW036qZR1CKAgYtRLWwvAERFj20mLJramei+hXZgxVa8FZlOxKLt3 7AE9A8PD1ZgnTiZUHzGoKibaknGVQn7+23C8Q5r0VDyPIXlEojVis1KLwJqTHl7O9i DdJSm6ank0afSC0eHcpC9ZpJdVzIIK8H09awoUPV70qcj0UpkaHqPrmxXaUMvpFB2f fXPdIGv/0AETg== Date: Wed, 17 Jul 2024 09:45:01 -0700 From: Jakub Kicinski To: Vladimir Oltean Cc: "Mogilappagari, Sudheer" , Michal Kubecek , "netdev@vger.kernel.org" , Wei Fang , "Samudrala, Sridhar" Subject: Re: Netlink handler for ethtool --show-rxfh breaks driver compatibility Message-ID: <20240717094501.2e60075d@kernel.org> In-Reply-To: <20240715154653.kcqcazsndp4nrqqh@skbuf> References: <20240711114535.pfrlbih3ehajnpvh@skbuf> <20240715115807.uc5nbc53rmthdbpu@skbuf> <20240715061137.3df01bf2@kernel.org> <20240715132253.jd7u3ompexonweoe@skbuf> <20240715063931.16bbe350@kernel.org> <20240715150543.wvqdfwzes4ptvd4m@skbuf> <20240715082600.770c1a89@kernel.org> <20240715154653.kcqcazsndp4nrqqh@skbuf> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 15 Jul 2024 18:46:53 +0300 Vladimir Oltean wrote: > > They can provide a different number? Which number is the user > > supposed to trust? Out of the 4 APIs we have? Or the NIC has > > a different ring count depending on the API? > > To stay on point on GRXRINGS vs GCHANNELS, "man ethtool" does say > "A channel is an IRQ and the set of queues that can trigger that IRQ." > Doesn't sound either (a) identical or (b) that you can recover the # of > rings from the # of channels, unless you make an assumption about how > they are distributed to IRQs... A bit short on time to write a proper reply, but thinking some more about it, I think you're right. The choice of channels is not great. It works today, but if we start stacking multiple Rx queues on a single IRQ one day - things will get complicated. So let's go back to GRXRINGS for now.