From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F17FC433EF for ; Tue, 10 May 2022 19:28:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231585AbiEJT2Q (ORCPT ); Tue, 10 May 2022 15:28:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243829AbiEJT1x (ORCPT ); Tue, 10 May 2022 15:27:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2875D39813 for ; Tue, 10 May 2022 12:27:31 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B0E20B81F70 for ; Tue, 10 May 2022 19:27:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3CCE2C385C2; Tue, 10 May 2022 19:27:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652210848; bh=5joIHAuRNLNHToSfeuBBqX17xHMOEVop/AOqjxOtWEw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=GEcQGy6dWjYB7Fa0gQmDktVJVtN2AcCcJJ92HHDg+73q+xNIHyymQaJlGuYyjHkH+ O5VBCXjdSWHSAlISobpUThlUsOurAjakCSUInapAEeXczXCXYUSWPb7Hm797FJ6GwV ilymEiUKGjP67yA06PzC10qc+/TM7dhu3NS9fmqu2CTEXzcJlCCdHEa80BvuN7Joio IyVBvteZnb2VIaPHQKlSZPR53ljSbuk9Cri2MlqkbXspNuD28z1yVEqFquCZnkoeWV zUZ8QNIhC587W5dyOIFWWtwM5S2oSlOAAnEJZJoLQ+67s7cHKfvDyTDhKW/vPFccfr INGTqHLNv9F8g== Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 45CF034E351; Tue, 10 May 2022 21:27:25 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Johannes Berg , Felix Fietkau , Alexander Wetzel Cc: linux-wireless@vger.kernel.org Subject: Re: [PATCH] mac80211: Simplify queue selection In-Reply-To: References: <20220510155828.9406-1-alexander@wetzel-home.de> <54589d98-882c-cee4-dd6d-140d50f400d0@nbd.name> X-Clacks-Overhead: GNU Terry Pratchett Date: Tue, 10 May 2022 21:27:25 +0200 Message-ID: <87tu9xw5lu.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Johannes Berg writes: > On Tue, 2022-05-10 at 18:10 +0200, Felix Fietkau wrote: >> On 10.05.22 17:58, Alexander Wetzel wrote: >> > Let iTXQ drivers also register four queues in netdev and move queue >> > assignment to ndo_select_queue(), like it's done for other drivers. >> > >> > This gets rid of a special case in mac80211 and also increases the >> > chance that when we call skb_get_hash() the skb is still hot in the CPU >> > buffers. >> > >> > Signed-off-by: Alexander Wetzel >> >> This has the disadvantage of requiring a redundant sta lookup in the tx >> path for iTXQ drivers. I think the CPU cost of that one is probably >> higher than any potential gain from calling skb_get_hash a bit earlier. >> > > However, that's independent - we can still calculate the hash there, and > then bail out, i.e. put it right before the "if (wake_tx_queue) return" > part, no? > > OTOH we don't even need the hash in the other cases, do we? Nope, that was my point on the "moving it to shared netdev core" question :) -Toke