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 B4F9436C; Fri, 14 Jun 2024 00:05:23 +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=1718323523; cv=none; b=ZTj/a1f1EwULgHlNM9/AG09cVxawMD37m9bxC7MoRBNmkQiUh1QHC8Y0gkna1kKsi2HydPitypwI5GSO+QVFww9QZPwBH5h/psDcY1BjO8Mm/tv6c0PD6gpLwhYNpHZekVoj64PeOOng3BHPszqTF9McPvodA0Xo6jF0HFBGPlM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718323523; c=relaxed/simple; bh=Tk/dh+spZSrmoPxZSBkQvt8dVNeejP0S+XKt7FjCMgE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=CXl8yJfI5L/js4UIbu7bHpKqJ6/+NAcFG5pvdnv9gnMoaA5i3FPLBtQdCQxQVesGQGycw+B8xrJ5LK/zKXCPUmVgIG0gSDXM7pUrrajedT/eWlwrZ19YCUfhRzx4YgcJeXIePX16Dn3iCNETVJDTg6dkI5SkbdtwIQYY/75KZn8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F3YK6jHZ; 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="F3YK6jHZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 055A0C2BBFC; Fri, 14 Jun 2024 00:05:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718323523; bh=Tk/dh+spZSrmoPxZSBkQvt8dVNeejP0S+XKt7FjCMgE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=F3YK6jHZweq8ERTiE2Yxuef/VSKTggOsD3eT2DybprJiyIinMBXHBgDO33Vn9b0Gp z6QLIFrO3lrHQJvsA0cNw/mA6i2XK9coEDWk70rHSmcKGpp5bcblOFuEOaw0vOqTEG sr9gTbinGnHBtB0VdX0UFtSYkq1Fw0VnZb/nN3i6k58Q3phgGdGhtwE6jgR14ILyul s4D1p5/Nbr+6sqr6yGGgGnN/Xgv+vC1SdKmgP6ZwE8nblTLbMMblrStn0W9T3fc1JN 1uQST6uaOgl19uEfKdQ+P+jK+DX0uFc+Llk+J2MzyJ04sSNVClEC7fvuQxihxnatkm Zz2FY9P/5YODA== Date: Thu, 13 Jun 2024 17:05:22 -0700 From: Jakub Kicinski To: Qingfang Deng Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Joe Perches , Qingfang Deng Subject: Re: [PATCH net-next] etherdevice: Optimize is_broadcast_ether_addr Message-ID: <20240613170522.0961c781@kernel.org> In-Reply-To: <20240613073441.781919-1-dqfext@gmail.com> References: <20240613073441.781919-1-dqfext@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-Transfer-Encoding: 7bit On Thu, 13 Jun 2024 15:34:41 +0800 Qingfang Deng wrote: > Like is_zero_ether_addr, is_broadcast_ether_addr can also be optimized > by using a 32-bit load if CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set. > Sign extension is used to populate the upper 16-bit of the 16-bit load. Can you provide more context on why it's beneficial. I mean, there's a lot of code in the kernel one could micro-optimize... Show us the assembly, cycle counts, where it's used on fast paths... -- pw-bot: cr