From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-x229.google.com (mail-lj1-x229.google.com [IPv6:2a00:1450:4864:20::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id E6D8C3B29E for ; Tue, 22 Nov 2022 15:48:20 -0500 (EST) Received: by mail-lj1-x229.google.com with SMTP id z4so2363919ljq.6 for ; Tue, 22 Nov 2022 12:48:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=OShCW4ZEymizKmEw6n2cPwJPTO3w4sfS72cti5BOs3Q=; b=GB4SwWvb2B/di1l7OtTuaJJiRy5CvL3SuDG9GH9S2Rk+LaxwDG3/nAO6vk1NC2neOQ u6H2kU7PTWqf9OfGF4NLbp2QsJPHJnhv5I2KSGQQhq5lmsa2FqQ4W5CLoRy2WrobWQOM vRVHTP6xwkhGnHLZP0kmzwDruBcXT3hyt7yd0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=OShCW4ZEymizKmEw6n2cPwJPTO3w4sfS72cti5BOs3Q=; b=lC1Kf+z8J6ERsDJbowS1Ky9x4Znhpcq0BmRY7tTTPaV9e4jjQgUHQ1ZEEmjnsq/9Tq KwLycFfozglWIbKABqLsTjWxophXqNpvlnJW4ROmkyA9dwsFn+QuNKcbvYu47QOm7PVK 2pBb0j40dCkSCoZ/e+xTLQSrpkZy/WeFtjvHP83WWYGeGpPokVHS996u9gAAWRMbfW0s Rlf9UrZbQ94YKAzeHzT2DQxZUXNPDQw7FEja/sJ/+InHBuRphnLDEyh5C2gvpQoEr+Tg opJFHujbICrBZgcGox553pujb+laj3ZklsNwi/6Itl3nc0LXCe40sgFM8LBgPyqu3NvA PZWw== X-Gm-Message-State: ANoB5pnBjCk2d8zYXClt39SqUq8B4JvXUEXpbP68V/2U6yFsmTrAtte9 7O5dtQByaa6Vo/MhenEIbMRBY+7xW27H67/PY7BmroLxU3M1x+B4Ht9mCtTwNyrabgYKJRS8dXK P79PqynXUM/DfEDteimB0F/PyFEK5twyPoBl74g== X-Google-Smtp-Source: AA0mqf4eb1Y3smn40XzIHV9FSN7nvSz95fEDgu03QmADB4YH2BD42MZU5aWzJLaAtc4ao+x+NXlxwy2kzEpGPpxN9Is= X-Received: by 2002:a05:651c:241:b0:26d:e38f:7e21 with SMTP id x1-20020a05651c024100b0026de38f7e21mr7761542ljn.273.1669150099340; Tue, 22 Nov 2022 12:48:19 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Bob McMahon Date: Tue, 22 Nov 2022 12:48:07 -0800 Message-ID: To: David Lang Cc: Dave Taht , Make-Wifi-fast , BBR Development , bloat Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="000000000000c7e4eb05ee154acf" Subject: Re: [Bloat] [Make-wifi-fast] [bbr-dev] Aggregating without bloating - hard times for tcp and wifi X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Nov 2022 20:48:21 -0000 --000000000000c7e4eb05ee154acf Content-Type: multipart/alternative; boundary="000000000000bff02005ee154a9c" --000000000000bff02005ee154a9c Content-Type: text/plain; charset="UTF-8" I don't know Qualcomm's offerings but here are some from Broadcom. https://www.broadcom.com/products/wireless/wireless-lan-infrastructure/bcm67263 The BCM4916 forwarding plane is done with a network processor and doesn't run Linux. Linux may be used to build the forwarding tables and this is standard "merchant silicon" forwarding approcch, let some CPU/stack build the topology tables and then realize the packet forwarding in (programmable) hardware. https://docs.broadcom.com/doc/4916-PB1XX Bob On Tue, Nov 22, 2022 at 12:28 PM Bob McMahon wrote: > Some main purposes of the WiFi CPU is 802.3 to 802.11 L2 translational > bridging and handling 802.11 protocols for things like association. Most > forwarded packets don't hit the main CPU anymore. This first sw to hw > transition occurred decades ago with real internet routers (equipment that > run IGPs and BGP) which started as software in the early 90s and then moved > to hardware. The same engineering has been happening for home gateways or > WiFi APs bridging wired to wireless. > > Bob > > On Tue, Nov 22, 2022 at 12:16 PM David Lang wrote: > >> sorry, when I was saying 'the cpu', I was meaning the main one running >> linux, >> not something that's part of the wifi chipset. >> >> I would be very surprised if the wifi chipset is doing any packet >> routing, as >> opposed to just sending the packets to the main processor. >> >> Remember, the common case isn't forwarding from one wifi device to >> another, it's >> moving between wifi devices and the wired uplink. >> >> David Lang >> >> On Tue, 22 Nov 2022, Bob McMahon wrote: >> >> > An AP's radio complex may have a CPU but that doesn't mean it is the >> > standard linux stack as most think of it. Many consider this as part of >> > "firmware" which can be Linux, a Linux derivative or other. Also, there >> > are some levels of wired/wireless forwarding plane integration done at >> the >> > hardware level that many might be surprised by. >> > >> > Bob >> > >> > On Tue, Nov 22, 2022 at 12:03 PM David Lang wrote: >> > >> >> On Tue, 22 Nov 2022, Bob McMahon via Make-wifi-fast wrote: >> >> >> >>> Finally, many (most?) APs are forwarding and feeding packets at at the >> >>> hardware level so not sure that the linux stack matters as much for >> an AP >> >>> based analysis, particularly when considering multi user >> transmissions, >> >>> i.e. multiple WiFi clients are active and sharing TXOPs. >> >> >> >> APs forward packets within the switch at the hardware level, but the >> >> radios have >> >> to go through the CPU, so any wired <-> wireless needs to go through >> the >> >> CPU, >> >> and I would be incredibly surprised if the wifi chips did wireless <-> >> >> wireless >> >> routing at the hardware level. >> >> >> >> David Lang >> >> >> > >> > >> > -- This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it. --000000000000bff02005ee154a9c Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I don't know Qualcomm's offerings=C2=A0but here ar= e some from Broadcom.

https://www.broadcom.com/prod= ucts/wireless/wireless-lan-infrastructure/bcm67263

The BCM4916 f= orwarding plane is done with a network processor and doesn't run Linux.= =C2=A0 Linux may be used to build the forwarding tables and this is standar= d "merchant=C2=A0silicon"=C2=A0forwarding approcch, let some CPU/= stack build the topology=C2=A0tables and then realize the packet forwarding= =C2=A0in (programmable) hardware.

https://docs.broadcom.com/doc/4916-PB1XX

Bob<= /div>
O= n Tue, Nov 22, 2022 at 12:28 PM Bob McMahon <bob.mcmahon@broadcom.com> wrote:
Some main purpose= s of the WiFi CPU is 802.3 to 802.11 L2 translational bridging and handling= 802.11 protocols for things like association. Most forwarded=C2=A0packets = don't hit the main CPU anymore. This=C2=A0first sw to hw transition occ= urred decades ago with real internet routers (equipment that run IGPs and B= GP) which started as software in the early 90s and then moved to hardware. = The same engineering has been=C2=A0happening for home gateways or WiFi APs = bridging wired to wireless.

Bob=C2=A0

On Tue, Nov 22, 2022 at 12:16 P= M David Lang <david@l= ang.hm> wrote:
sorry, when I was saying 'the cpu', I was meaning the main on= e running linux,
not something that's part of the wifi chipset.

I would be very surprised if the wifi chipset is doing any packet routing, = as
opposed to just sending the packets to the main processor.

Remember, the common case isn't forwarding from one wifi device to anot= her, it's
moving between wifi devices and the wired uplink.

David Lang

On Tue, 22 Nov 2022, Bob McMahon wrote:

> An AP's radio complex may have a CPU but that doesn't mean it = is the
> standard linux stack as most think of it. Many consider this as part o= f
> "firmware" which can be Linux, a Linux derivative or other.= =C2=A0 Also, there
> are some levels of wired/wireless forwarding plane integration done at= the
> hardware level that many might be surprised by.
>
> Bob
>
> On Tue, Nov 22, 2022 at 12:03 PM David Lang <david@lang.hm> wrote:
>
>> On Tue, 22 Nov 2022, Bob McMahon via Make-wifi-fast wrote:
>>
>>> Finally, many (most?) APs are forwarding and feeding packets a= t at the
>>> hardware level so not sure that the linux stack matters as muc= h for an AP
>>> based analysis, particularly when considering multi user trans= missions,
>>> i.e. multiple WiFi clients are active and sharing TXOPs.
>>
>> APs forward packets within the switch at the hardware level, but t= he
>> radios have
>> to go through the CPU, so any wired <-> wireless needs to go= through the
>> CPU,
>> and I would be incredibly surprised if the wifi chips did wireless= <->
>> wireless
>> routing at the hardware level.
>>
>> David Lang
>>
>
>

This ele= ctronic communication and the information and any files transmitted with it= , or attached to it, are confidential and are intended solely for the use o= f the individual or entity to whom it is addressed and may contain informat= ion that is confidential, legally privileged, protected by privacy laws, or= otherwise restricted from disclosure to anyone else. If you are not the in= tended recipient or the person responsible for delivering the e-mail to the= intended recipient, you are hereby notified that any use, copying, distrib= uting, dissemination, forwarding, printing, or copying of this e-mail is st= rictly prohibited. If you received this e-mail in error, please return the = e-mail to the sender, delete it from your computer, and destroy any printed= copy of it. --000000000000bff02005ee154a9c-- --000000000000c7e4eb05ee154acf Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIIQagYJKoZIhvcNAQcCoIIQWzCCEFcCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg gg3BMIIFDTCCA/WgAwIBAgIQeEqpED+lv77edQixNJMdADANBgkqhkiG9w0BAQsFADBMMSAwHgYD VQQLExdHbG9iYWxTaWduIFJvb3QgQ0EgLSBSMzETMBEGA1UEChMKR2xvYmFsU2lnbjETMBEGA1UE AxMKR2xvYmFsU2lnbjAeFw0yMDA5MTYwMDAwMDBaFw0yODA5MTYwMDAwMDBaMFsxCzAJBgNVBAYT AkJFMRkwFwYDVQQKExBHbG9iYWxTaWduIG52LXNhMTEwLwYDVQQDEyhHbG9iYWxTaWduIEdDQyBS MyBQZXJzb25hbFNpZ24gMiBDQSAyMDIwMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA vbCmXCcsbZ/a0fRIQMBxp4gJnnyeneFYpEtNydrZZ+GeKSMdHiDgXD1UnRSIudKo+moQ6YlCOu4t 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