From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-04.galae.net (smtpout-04.galae.net [185.171.202.116]) (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 45ED3401A13 for ; Thu, 4 Jun 2026 09:09:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.171.202.116 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780564144; cv=none; b=lU/WZuaLnVV5mID/lQlKna2kTrCk4hUc30NvYY5zTybTQGXzGJs+e9WUEUCAdNY0IZ0KaVum2iRxAyIfVd+AehfBpT3Z+sWpnbfh+mWLj3to3eQG/0eWdtkpR5Waj0bYpVUfE4X3zeEwiN6kyAsQpfiCHadE3RfGZvejJa2MJwY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780564144; c=relaxed/simple; bh=uc00VLcog2WfkxxWWJqpT2Obgov4mLLl8LSCSoJjTjk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=DIg6PQ2J8TSA1/1AwHNHxc7IR5CBsWk2lM/8z5DeJWGSC3GWtljp9KoWWbTVMiZmNe2CxNvMmxDQkcwCBFxqfCYncBK2GvZKy50r1vOtS40KOqzu9dPVlrygnp8ukPfTGnFEk0q0KvyPqBjP61D5zS2NswJov9qjuQVhCCoCHb8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=g9RMeIGB; arc=none smtp.client-ip=185.171.202.116 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="g9RMeIGB" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id 7C194C6344D; Thu, 4 Jun 2026 09:08:54 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 3C5285FEF7; Thu, 4 Jun 2026 09:08:55 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 2CD33106A157A; Thu, 4 Jun 2026 11:08:48 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1780564134; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=4srTPRj0v03/Rg5p6EvI3FZ1fKDS+khyaN2aDtnMGC0=; b=g9RMeIGB3rFIgWSWkMjyN7yxGTGvvmcx238cAmEaOEHKpTLIJLqOXgUM06dMi3bB1W5Wnn rTDX0p4v7+OHUvoa7YkpkYkAJj70uqY5iPpEQEueUo87u9b0fgM6cZhlFdTsdn2C4NmJP/ 7pStr2bUdgg5zOPDXVXEcXHhSKB9WBaNLzBOMpLrWuUrEgVuUUg7/4TqM30uzfLw8ndEI1 4iusgDcNUExGUEnT22LPl3E52IfQXFx0AKqiRBvRGBYs2F04yY6AzbcF+asLXlZcS7qtNv 7jWSohrGmc2+u+VMT4sPacrjZxzEDKXZ+wh0ljQO5v0NjECbkXz7ytO6Y9KY6Q== Message-ID: <90716dc8-f10f-4777-9939-829f7e8b84ca@bootlin.com> Date: Thu, 4 Jun 2026 11:08:48 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] net: stmmac: xgmac2: disable RBUE in default RX interrupt mask To: "Nazle Asmade, Muhammad Nazim Amirul" , "netdev@vger.kernel.org" Cc: "andrew+netdev@lunn.ch" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "mcoquelin.stm32@gmail.com" , "alexandre.torgue@foss.st.com" , "rmk+kernel@armlinux.org.uk" , "Jose.Abreu@synopsys.com" , "linux-kernel@vger.kernel.org" References: <20260529071734.27722-1-muhammad.nazim.amirul.nazle.asmade@altera.com> <6837ed21-196a-48dd-b8b0-0f6691a946d0@altera.com> Content-Language: en-US From: Maxime Chevallier In-Reply-To: <6837ed21-196a-48dd-b8b0-0f6691a946d0@altera.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 Hi, >> to note that it'll >> now make the "rx_buf_unav_irq" stat (that we can query from userspace) >> stuck at 0 now. >> >> That's a user-visible behaviour change, for a stat that can be useful, >> one could consider that a uAPI change... >> >> Do you have some numbers on the perf impact you see when buffer >> starvation hits to see what we are gaining/losing here ? >> >> Maxime >> > Hi Maxime, > > Thank you for the review and for pointing out the rx_buf_unav_irq concern. > > We do have interrupt storm data to share. On Agilex5, under heavy RX > pressure we observed: > > Under heavy RX pressure we observed eth0:mac firing 1,821,811,555 times > vs 2,618,627 actual RX completions on eth0:rx-0 — a ~695x ratio. Ouch indeed. The stat itself has to stay, but the behaviour of that counter is already different depending on the DWMAC core version. I think we can get this patch in, but please state in the commit message the performance measurements you're mentioning, as well as the fact that the counter will now always show at 0 on XGMAC2 devices. Maybe we'll eventually need some switch to toggle these counters, as it's some valuable information when debugging, but has a significant impact on speeds. With the commit log updates, Reviewed-by: Maxime Chevallier > > BR, > Nazim