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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BDF0C43613 for ; Wed, 19 Jun 2019 20:09:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F07CD2084A for ; Wed, 19 Jun 2019 20:09:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726322AbfFSUJP (ORCPT ); Wed, 19 Jun 2019 16:09:15 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:33920 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbfFSUJP (ORCPT ); Wed, 19 Jun 2019 16:09:15 -0400 Received: by mail-wr1-f66.google.com with SMTP id k11so600854wrl.1 for ; Wed, 19 Jun 2019 13:09:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=vDOHCyvMK/Vb7odmOhJJhUOHp65K6oTP+Z5A/bmIxdM=; b=bpIJz2qou1QOmq763a6/EVtgPQl61NYmBpOX6dmhDXIryVU63jS3GUUItQ9UjVR9uL DUFZ9qA2Lako/mhkfYUIgY2Qz+E+vddfgqHPd2XHn/hcgVyPZwRIdTWiwJ/AUnPwI1f4 fU5W2Nwb8XfWNnKLzXQbdofAi36arbfDOE1aPMSN67nHRVrPHQwvDDIqQhDwSL+2qwqM 22d/CYQHQ4XCu6Tr2x0LTjSR7nr2J1jCZ0Hts9lG3RCF4MiEuwCJci+pCf5I74VNBT6u ajcpUV9n400iZUziV6rj7yUMkZfRnXmzNoUzmMk643h9b8LzzAxvQEEYig2QZ7VY06iG a/xA== X-Gm-Message-State: APjAAAXkKUB7E9DeMRVumIE0L6fD3TwfKTyZE1k56LFfnuqNcDslAT7Q /12d08ziG4u0wsVIEgxw+CeEeA== X-Google-Smtp-Source: APXvYqz9Xpfb5anMktOhqf1eTTzMC0XonQqPfIg8VqohVHFAg5pCXal3HtPqRKlpfrYXiQe/iA7R5w== X-Received: by 2002:adf:ebcd:: with SMTP id v13mr13393080wrn.263.1560974952650; Wed, 19 Jun 2019 13:09:12 -0700 (PDT) Received: from lore-desk-wlan ([151.66.61.123]) by smtp.gmail.com with ESMTPSA id r131sm2731444wmf.4.2019.06.19.13.09.11 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 19 Jun 2019 13:09:12 -0700 (PDT) Date: Wed, 19 Jun 2019 22:09:09 +0200 From: Lorenzo Bianconi To: Stanislaw Gruszka Cc: Lorenzo Bianconi , kvalo@codeaurora.org, linux-wireless@vger.kernel.org, nbd@nbd.name Subject: Re: [PATCH v3 wireless-drivers 3/3] mt76: usb: do not always copy the first part of received frames Message-ID: <20190619200908.GA31657@lore-desk-wlan> References: <1a9566c0a41ad0d940487a9d3f0008993c075ef2.1560461404.git.lorenzo@kernel.org> <20190614075303.GB3395@redhat.com> <20190614102247.GB2669@localhost.localdomain> <20190614110442.GA17298@redhat.com> <20190614124635.GD2669@localhost.localdomain> <20190615094016.GA20197@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Nq2Wo0NMKNjxTN9z" Content-Disposition: inline In-Reply-To: <20190615094016.GA20197@redhat.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org --Nq2Wo0NMKNjxTN9z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > On Fri, Jun 14, 2019 at 02:46:36PM +0200, Lorenzo Bianconi wrote: > > > >=20 > > > > ack, right. I think patch 2/3 and 3/3 can go directly in Felix's tr= ee > > > >=20 > > > > >=20 > > > > > > + int i, data_size; > > > > > > =20 > > > > > > + data_size =3D rounddown(SKB_WITH_OVERHEAD(q->buf_size), > > > > > > + dev->usb.in_ep[MT_EP_IN_PKT_RX].max_packet); > > > > > > for (i =3D 0; i < nsgs; i++) { > > > > > > struct page *page; > > > > > > void *data; > > > > > > @@ -302,7 +304,7 @@ mt76u_fill_rx_sg(struct mt76_dev *dev, stru= ct mt76_queue *q, struct urb *urb, > > > > > > =20 > > > > > > page =3D virt_to_head_page(data); > > > > > > offset =3D data - page_address(page); > > > > > > - sg_set_page(&urb->sg[i], page, q->buf_size, offset); > > > > > > + sg_set_page(&urb->sg[i], page, data_size, offset); > > > > > > > > > > > - q->buf_size =3D dev->usb.sg_en ? MT_RX_BUF_SIZE : PAGE_SIZE; > > > > > > q->ndesc =3D MT_NUM_RX_ENTRIES; > > > > > > + q->buf_size =3D PAGE_SIZE; > > > > > > + > > > > >=20 > > > > > This should be associated with decrease of MT_SG_MAX_SIZE to valu= e that > > > > > is actually needed and currently this is 2 for 4k AMSDU. > > > >=20 > > > > MT_SG_MAX_SIZE is used even on tx side and I do not think we will e= nd up with a > > > > huge difference here > > >=20 > > > So use different value as argument for mt76u_fill_rx_sg() in > > > mt76u_rx_urb_alloc(). After changing buf_size to PAGE_SIZE we will > > > allocate 8 pages per rx queue entry, but only 2 pages will be used > > > (with data_size change, 1 without data_size change). Or I'm wrong? > >=20 > > yes, it is right (we will use two pages with data_size change). Maybe b= etter to > > use 4 pages for each rx queue entry? (otherwise we will probably change= it in > > the future) >=20 > We should not allocate more than is required. If support for bigger > rx AMSDUs will be added and announced in vht/ht capabilities to remote > stations, then increase of number of segments will be needed. >=20 > > > > > However I don't think allocating 2 pages to avoid ieee80211 heade= r and SNAP > > > > > copy is worth to do. For me best approach would be allocate 1 pag= e for > > > > > 4k AMSDU, 2 for 8k and 3 for 12k (still using sg, but without dat= a_size > > > > > change to avoid 32B copying). > > > >=20 > > > > From my point of view it is better to avoid copying if it is possib= le. Are you > > > > sure there is no difference? > > >=20 > > > I do not understand what you mean by difference here. > >=20 > > tpt differences, not sure if there are any >=20 > I would not expect any measurable difference in tpt nor in cpu usage > either way. >=20 > But I think, if some AMSDU subframe will be spited into two fragments, > data most likely will need to be linearised/copied, at some point before > passed to application, what will overcome any benefit of avoiding coping > 802.11 header. Thought, I don't think this somehow will be visible in > benchmarking. Sorry for the late reply. I think so. I will post a v4 soon. Regards, Lorenzo >=20 > Stanislaw --Nq2Wo0NMKNjxTN9z Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCXQqWYQAKCRA6cBh0uS2t rCyfAP46TBPYzq84Lab3fUrA/jmFXXAKOSdiM1Ff806lZXDpMwD/Qy+haDSTSGRA zz+nYDwDEohDprlWUfbxU+cdEyZ7og8= =AvEW -----END PGP SIGNATURE----- --Nq2Wo0NMKNjxTN9z--