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 4CEE2C38142 for ; Sat, 28 Jan 2023 12:07:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234112AbjA1MHE (ORCPT ); Sat, 28 Jan 2023 07:07:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234103AbjA1MHC (ORCPT ); Sat, 28 Jan 2023 07:07:02 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45E1879604 for ; Sat, 28 Jan 2023 04:07:01 -0800 (PST) From: Kurt Kanzenbach DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1674907620; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ew47kVxKqM6FwWvR58a7SRrFfJ+KifPWcx17XtrGqxY=; b=HuGAAjP15oOTYK99WgdtuORnvBO5OgAeQaWOaycWAE7tkdAqun8VHYdvX0k1Mo6IBnOc2c S+4qZxJvGGFrur7szAvc3niYXB7DUW3N8lNsuTq/P7KD1ADB0sespXCj8tJPuBgqhDa99P xKoF/hL+VTbzNrX1ElDR6/mgbO3j2VU0S79YIUcmkCGPTiHdoFaOvk87TaIF5l9Gxa3F53 97x42NUYY399uICLG8/5b5F+Lxopgs0LbxHtx5GzMo6ShTpJ9XiKJNyOytIRpN2m5QDP+T vYzp0Mh4ZsfYykEn9z3ub1KOGj7PGGs5IckAI+DxZZDR1ArV9HDvnxoj/LJBJQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1674907620; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ew47kVxKqM6FwWvR58a7SRrFfJ+KifPWcx17XtrGqxY=; b=t4HO/h9Jw4dokyinXdWIaKBz5CEtWqkT463SnjWi28CdBrzBKZKjSOznC3Kswowmk9gMCS svYrvoSNbwIUIXAQ== To: Vladimir Oltean , netdev@vger.kernel.org Cc: Vinicius Costa Gomes Subject: Re: [RFC PATCH net-next 13/15] net/sched: taprio: automatically calculate queueMaxSDU based on TC gate durations In-Reply-To: <20230128010719.2182346-14-vladimir.oltean@nxp.com> References: <20230128010719.2182346-1-vladimir.oltean@nxp.com> <20230128010719.2182346-14-vladimir.oltean@nxp.com> Date: Sat, 28 Jan 2023 13:06:58 +0100 Message-ID: <87wn56ual9.fsf@kurt> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org --=-=-= Content-Type: text/plain On Sat Jan 28 2023, Vladimir Oltean wrote: > taprio today has a huge problem with small TC gate durations, because it > might accept packets in taprio_enqueue() which will never be sent by > taprio_dequeue(). > > Since not much infrastructure was available, a kludge was added in > commit 497cc00224cf ("taprio: Handle short intervals and large > packets"), which segmented large TCP segments, but the fact of the > matter is that the issue isn't specific to large TCP segments (and even > worse, the performance penalty in segmenting those is absolutely huge). > > In commit a54fc09e4cba ("net/sched: taprio: allow user input of per-tc > max SDU"), taprio gained support for queueMaxSDU, which is precisely the > mechanism through which packets should be dropped at qdisc_enqueue() if > they cannot be sent. > > After that patch, it was necessary for the user to manually limit the > maximum MTU per TC. This change adds the necessary logic for taprio to > further limit the values specified (or not specified) by the user to > some minimum values which never allow oversized packets to be sent. > > Signed-off-by: Vladimir Oltean Reviewed-by: Kurt Kanzenbach --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJHBAEBCgAxFiEEvLm/ssjDfdPf21mSwZPR8qpGc4IFAmPVD+MTHGt1cnRAbGlu dXRyb25peC5kZQAKCRDBk9HyqkZzgu+ZEACYX4yinrSPzpRynQQ6AleKYB8UqfKy Fo+iEhRM28rmKmIrzY3SJlWUVAGmpWPhK7iqNf2S17ZuI5WOI4Uq9qc+fS7XDPrc ehc0WlkbLm7TVFaS/lzpYsEijIfusE+pAQG1l8r4x+cs8w/k1vqWa6iUrOaphvZe hxOo2rMvtvY8k9qQklml2D5RYVyYcdRrK3D8PNOau1RSxsrkKCXB9bgSNVupdeqg rXZwcBRetk5ZQS6Se3Xc/Nhpz7zs/Vr8il35YjgUlyMStWyTMlAacziJAiprm0vz t9ouF4CL73AUxoDuYy4HVDQI6eZiMwMECqW687ld6ui3qQH8PjxuC+uvDOl86nNL D1ueVOhI6blQj8MOjsT3e4h0JOPXJWAWrvreEHHCYcDc7ZDALs+bPu4N03ETddCU xWWK8en4PDpJUBlY7eI0WuvcqDF3lE5eLoSh9Dz7Lo42SbQW/6CfxFrPCqlZe96c 9W2zDLEIpCg0vtNnhLxGnkid/M1Y7Tc0eo/2ghgTLYfX6MMnblGR3lKKF10VYpf9 3z3PdkONTjAM+bbHz+WgN9QPZqyFR5PLLBRddkcVl06JLAzl+/tqlx6YJwRPsgUw PZ4pzjr2shg//m8YU5sSgoNHFIZi9XDr0nnoktuixfKVt6Q/EC04FyS6PKMP9JH2 +rohcK+W3c9DSQ== =qAQ0 -----END PGP SIGNATURE----- --=-=-=--