From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 200611D63DE for ; Tue, 14 Jan 2025 23:31:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736897470; cv=none; b=nVX2qra0EpXFjRrkO/hRmSs/tY6KcaPa6kLSpFEPCfEHWxzBXRnXH+uZqQh5wmRR8leqs9/ntUyecno0aLeX6/b6sX+NC7upL5KHCi6F/aF/GfycZhj2GZL4ygRuua0JLqb8ikxOQsfHluZulZ4hvkj4y+z3HyK/lHLtUQ1CAvA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736897470; c=relaxed/simple; bh=7njtDU+cbFEo7DWmybdpzgKaGHQxVB9WlDBRFXzaM6o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Dom86G2svrQEzEH2BzO6FzNh9C2qSoEgS52JSlxqlaqknWBKttjvnXAvqqGn32h+O5QvQvQO0rq+mCJay+F5dObAmVcpOKh+9H4rOZmeoOm3eIT9Ph/1XVTwuUEeoSJ5UQOIpl2mudOQABm1GSJWB3HGCb1WtvA5+dJRpEjxpuU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com; spf=pass smtp.mailfrom=fastly.com; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b=KnHW8luu; arc=none smtp.client-ip=209.85.214.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fastly.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b="KnHW8luu" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-2164b1f05caso108371815ad.3 for ; Tue, 14 Jan 2025 15:31:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1736897468; x=1737502268; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date:from:to:cc :subject:date:message-id:reply-to; bh=QB7Gju0RIgr9jLJ+t5Q7M0pre/bo/tmwE6J1WO4l68M=; b=KnHW8luu/gtGA037zc4CG/94FiPbPdCgfw/qKl/VmJpJh6Al3GpBSG1vy2xxhGONBg gt+L0QA0dmIIe1TUiNZ2ErtCdEu4M3M+KGJEXfrbbLRDDh0DwDVeMBXCQ8he99raATot z5ZGArbAywAsJBZ8AZjWrMAmaCtBdPsb+FcHY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736897468; x=1737502268; h=in-reply-to:content-disposition:mime-version:references :mail-followup-to:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=QB7Gju0RIgr9jLJ+t5Q7M0pre/bo/tmwE6J1WO4l68M=; b=KIuCdy0sCWhEncT2fzIi+fKVuuBjI+VuwPVLvB+WcvccKdagbH6a/915WaR2rudI3J iTlVCRpLUxtFgMrj75b5bt0lbjKVMmNEfUz895FtKbFvuxXSJ/rm2CNRbYkxB1E2QtBD VqoCxPAppLJCnoXYjovKBa3KRvh24AsKaHQ9VwLI4TUznhTSJtRyikiACBXr0PXtK/bb ARHpSnmn8EYS3zkhUzxUdh+NtOWi0+fBzW9WzP4YT83Kg0RTkd3cJLT/B534oUmz2k7+ GGnR4rLput+75TahLt9Zw05EzLAPnOc4nAi2RaO3YaoaIgtY1PBVwTvPBDqF0EaLa6aM EHZg== X-Gm-Message-State: AOJu0YwA6KXFggXBd1KJa/U08UZ6wxYeJ2Mz11gJ0rLusgx0lD2T9zkf ydBmVHEP0YQ3vXHD1ZHdpLIUfmvrQTf4K9qjceJtiFjueg78ljhAMqgyPY8VAWA= X-Gm-Gg: ASbGncvHkAqSEgwLtCbQ3jTgp1tdgII9YAZtteM4U3yNCrgegeoMhUGtk8NxGHpZCvy DkOIKYn17aOqVmT3GuvUW4+nAxdhCfAUmQWGTLAq59x98L8xij/n/jcGxWaheLxaJJMaES+rr2m 7u/0V49PhtTJvFAzDtJIHhI5qY+A5v2wHvkhbxrsY/Vwrr2M+ZUG2vd3w/kNgeizJhKKYWWzSue JdOeybGTN8FseDaC4/XCDM9ve/rB274WuzsPY6K/EGNrJt/n/o9qB3Cm+Eb7bK4thffT1Wtu0CT 9E9Htj/BJwgqW+bHkJRNtS4= X-Google-Smtp-Source: AGHT+IHovqEE/ZGS2FK/ULFvVF1bTBtDYpXgDWtKvoluSSVf7ExMHwXGJ8cq8SZ8vVf7DFdkQBZM8A== X-Received: by 2002:a05:6a00:4f88:b0:729:a31:892d with SMTP id d2e1a72fcca58-72d21fa5cecmr42495186b3a.8.1736897468403; Tue, 14 Jan 2025 15:31:08 -0800 (PST) Received: from LQ3V64L9R2 (c-24-6-151-244.hsd1.ca.comcast.net. [24.6.151.244]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-72d405943fcsm7955165b3a.78.2025.01.14.15.31.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jan 2025 15:31:07 -0800 (PST) Date: Tue, 14 Jan 2025 15:31:05 -0800 From: Joe Damato To: Furong Xu <0x1207@gmail.com> Cc: netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexander Lobakin , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , xfr@outlook.com Subject: Re: [PATCH net-next v2 3/3] net: stmmac: Optimize cache prefetch in RX path Message-ID: Mail-Followup-To: Joe Damato , Furong Xu <0x1207@gmail.com>, netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexander Lobakin , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , xfr@outlook.com References: <668cfa117e41a0f1325593c94f6bb739c3bb38da.1736777576.git.0x1207@gmail.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=us-ascii Content-Disposition: inline In-Reply-To: <668cfa117e41a0f1325593c94f6bb739c3bb38da.1736777576.git.0x1207@gmail.com> On Mon, Jan 13, 2025 at 10:20:31PM +0800, Furong Xu wrote: > Current code prefetches cache lines for the received frame first, and > then dma_sync_single_for_cpu() against this frame, this is wrong. > Cache prefetch should be triggered after dma_sync_single_for_cpu(). > > This patch brings ~2.8% driver performance improvement in a TCP RX > throughput test with iPerf tool on a single isolated Cortex-A65 CPU > core, 2.84 Gbits/sec increased to 2.92 Gbits/sec. > > Signed-off-by: Furong Xu <0x1207@gmail.com> > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index ca340fd8c937..b60f2f27140c 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -5500,10 +5500,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) > > /* Buffer is good. Go on. */ > > - prefetch(page_address(buf->page) + buf->page_offset); > - if (buf->sec_page) > - prefetch(page_address(buf->sec_page)); > - > buf1_len = stmmac_rx_buf1_len(priv, p, status, len); > len += buf1_len; > buf2_len = stmmac_rx_buf2_len(priv, p, status, len); > @@ -5525,6 +5521,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue) > > dma_sync_single_for_cpu(priv->device, buf->addr, > buf1_len, dma_dir); > + prefetch(page_address(buf->page) + buf->page_offset); Minor nit: I've seen in other drivers authors using net_prefetch. Probably not worth a re-roll just for something this minor.