From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120] helo=us-smtp-1.mimecast.com) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAL49-0005WW-Ov for ath10k@lists.infradead.org; Tue, 17 Sep 2019 21:31:19 +0000 Received: by mail-ed1-f70.google.com with SMTP id s3so3003789edr.15 for ; Tue, 17 Sep 2019 14:31:10 -0700 (PDT) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= Subject: Re: [PATCH 1/4] mac80211: Switch to a virtual time-based airtime scheduler In-Reply-To: <1568639388-27291-1-git-send-email-yiboz@codeaurora.org> References: <1568639388-27291-1-git-send-email-yiboz@codeaurora.org> Date: Tue, 17 Sep 2019 23:31:08 +0200 Message-ID: <87ftkuip9f.fsf@toke.dk> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: Yibo Zhao , ath10k@lists.infradead.org Cc: linux-wireless@vger.kernel.org WWlibyBaaGFvIDx5aWJvekBjb2RlYXVyb3JhLm9yZz4gd3JpdGVzOgoKPiBGcm9tOiBUb2tlIEjD uGlsYW5kLUrDuHJnZW5zZW4gPHRva2VAcmVkaGF0LmNvbT4KPgo+IFRoaXMgc3dpdGNoZXMgdGhl IGFpcnRpbWUgc2NoZWR1bGVyIGluIG1hYzgwMjExIHRvIHVzZSBhIHZpcnR1YWwgdGltZS1iYXNl ZAo+IHNjaGVkdWxlciBpbnN0ZWFkIG9mIHRoZSByb3VuZC1yb2JpbiBzY2hlZHVsZXIgdXNlZCBi ZWZvcmUuIFRoaXMgaGFzIGEKPiBjb3VwbGUgb2YgYWR2YW50YWdlczoKPgo+IC0gTm8gbmVlZCB0 byBzeW5jIHVwIHRoZSByb3VuZC1yb2JpbiBzY2hlZHVsZXIgaW4gZmlybXdhcmUvaGFyZHdhcmUg d2l0aAo+ICAgdGhlIHJvdW5kLXJvYmluIGFpcnRpbWUgc2NoZWR1bGVyLgo+Cj4gLSBJZiBzZXZl cmFsIHN0YXRpb25zIGFyZSBlbGlnaWJsZSBmb3IgdHJhbnNtaXNzaW9uIHdlIGNhbiBzY2hlZHVs ZSBib3RoIG9mCj4gICB0aGVtOyBubyBuZWVkIHRvIGhhcmQtYmxvY2sgdGhlIHNjaGVkdWxpbmcg cm90YXRpb24gdW50aWwgdGhlIGhlYWQgb2YgdGhlCj4gICBxdWV1ZSBoYXMgdXNlZCB1cCBpdHMg cXVhbnR1bS4KPgo+IC0gVGhlIGNoZWNrIG9mIHdoZXRoZXIgYSBzdGF0aW9uIGlzIGVsaWdpYmxl IGZvciB0cmFuc21pc3Npb24gYmVjb21lcwo+ICAgc2ltcGxlciAoaW4gaWVlZTgwMjExX3R4cV9t YXlfdHJhbnNtaXQoKSkuCj4KPiBUaGUgZHJhd2JhY2sgaXMgdGhhdCBzY2hlZHVsaW5nIGJlY29t ZXMgc2xpZ2h0bHkgbW9yZSBleHBlbnNpdmUsIGFzIHdlIG5lZWQKPiB0byBtYWludGFpbiBhbiBy YnRyZWUgb2YgVFhRcyBzb3J0ZWQgYnkgdmlydHVhbCB0aW1lLiBUaGlzIG1lYW5zIHRoYXQKPiBp ZWVlODAyMTFfcmVnaXN0ZXJfYWlydGltZSgpIGJlY29tZXMgTyhsb2dOKSBpbiB0aGUgbnVtYmVy IG9mIGN1cnJlbnRseQo+IHNjaGVkdWxlZCBUWFFzLiBIb3dldmVyLCBob3BlZnVsbHkgdGhpcyBu dW1iZXIgcmFyZWx5IGdyb3dzIHRvbyBiaWcgKGl0J3MKPiBvbmx5IFRYUXMgY3VycmVudGx5IGJh Y2tsb2dnZWQsIG5vdCBhbGwgYXNzb2NpYXRlZCBzdGF0aW9ucyksIHNvIGl0Cj4gc2hvdWxkbid0 IGJlIHRvbyBiaWcgb2YgYW4gaXNzdWUuCj4KPiBTaWduZWQtb2ZmLWJ5OiBUb2tlIEjDuGlsYW5k LUrDuHJnZW5zZW4gPHRva2VAcmVkaGF0LmNvbT4KCkknbGwgbm90ZSB0aGF0IHRoaXMgcGF0Y2gg c3RpbGwgaGFzIHRoZSB0d28gaXNzdWVzIHRoYXQgRmVsaXggcG9pbnRlZApvdXQgd2hlbiBJIHBv c3RlZCB0aGUgUkZDIHZlcnNpb24uIE5hbWVseToKCi0gVGhlIHVzZSBvZiBkaXZpc2lvbnMgaW4g dGhlIGZhc3QgcGF0aC4gSSBndWVzcyBJIG5lZWQgdG8gZ28gd3JpdGUgc29tZQogIHJlY2lwcm9j YWwtY2FsY3VsYXRpb24gY29kZSwgc2luY2UgdGhhdCBpcyBhbHNvIGFuIGlzc3VlIHdpdGggdGhl IEFRTAogIHBhdGNoZXMgSSBsaW5rZWQgdG8gYmVmb3JlLgoKLSBUaGUgZmFjdCB0aGF0IHdlIGRv bid0IGNvdW50IHRoZSBhaXJ0aW1lIHVzYWdlIG9mIG11bHRpY2FzdCB0cmFmZmljLAogIHdoaWNo IHdpdGggdGhpcyBzZXJpZXMgbWVhbnMgdGhhdCB0aGUgdmlmIFRYUSB3aWxsIGdldCBwcmlvcml0 eSBvdmVyCiAgdGhlIG90aGVycy4gSSB0aGluayB3ZSBhZ3JlZWQgdG8gZml4IHRoaXMgYnkganVz dCBhZGRpbmcgYW4gYWlydGltZQogIHZfdCB0byB0aGUgdmlmIGFzIHdlbGwgYW5kIHVzZSB0aGF0 IGZvciBzY2hlZHVsaW5nIHRoZSBUWFEuIERvZXMKICBhdGgxMGsgcmVwb3J0IGFpcnRpbWUgdXNh Z2UgZm9yIG11bHRpY2FzdCBhcyB3ZWxsLCBvciBvbmx5IGZvcgogIHN0YXRpb25zPwoKCi1Ub2tl CgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KYXRoMTBr IG1haWxpbmcgbGlzdAphdGgxMGtAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5m cmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2F0aDEwawo= 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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 4BD59C4CECD for ; 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Tue, 17 Sep 2019 14:31:09 -0700 (PDT) X-Google-Smtp-Source: APXvYqx1wjlX98Jj01zS5MwohtCyWE1osliaa7sfDb/BoubXMW52uGvVGR84W7o5lDopiiD4H9If2Q== X-Received: by 2002:a05:6402:78b:: with SMTP id d11mr4964726edy.14.1568755869581; Tue, 17 Sep 2019 14:31:09 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([2a00:7660:6da:443::2]) by smtp.gmail.com with ESMTPSA id z39sm638848edd.46.2019.09.17.14.31.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Sep 2019 14:31:08 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 62B041800B9; Tue, 17 Sep 2019 23:31:08 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Yibo Zhao , ath10k@lists.infradead.org Cc: linux-wireless@vger.kernel.org Subject: Re: [PATCH 1/4] mac80211: Switch to a virtual time-based airtime scheduler In-Reply-To: <1568639388-27291-1-git-send-email-yiboz@codeaurora.org> References: <1568639388-27291-1-git-send-email-yiboz@codeaurora.org> X-Clacks-Overhead: GNU Terry Pratchett Date: Tue, 17 Sep 2019 23:31:08 +0200 Message-ID: <87ftkuip9f.fsf@toke.dk> MIME-Version: 1.0 X-MC-Unique: zz7xyQe-OpefX9rBv39ONA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Yibo Zhao writes: > From: Toke H=C3=B8iland-J=C3=B8rgensen > > This switches the airtime scheduler in mac80211 to use a virtual time-bas= ed > scheduler instead of the round-robin scheduler used before. This has a > couple of advantages: > > - No need to sync up the round-robin scheduler in firmware/hardware with > the round-robin airtime scheduler. > > - If several stations are eligible for transmission we can schedule both = of > them; no need to hard-block the scheduling rotation until the head of t= he > queue has used up its quantum. > > - The check of whether a station is eligible for transmission becomes > simpler (in ieee80211_txq_may_transmit()). > > The drawback is that scheduling becomes slightly more expensive, as we ne= ed > to maintain an rbtree of TXQs sorted by virtual time. This means that > ieee80211_register_airtime() becomes O(logN) in the number of currently > scheduled TXQs. However, hopefully this number rarely grows too big (it's > only TXQs currently backlogged, not all associated stations), so it > shouldn't be too big of an issue. > > Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen I'll note that this patch still has the two issues that Felix pointed out when I posted the RFC version. Namely: - The use of divisions in the fast path. I guess I need to go write some reciprocal-calculation code, since that is also an issue with the AQL patches I linked to before. - The fact that we don't count the airtime usage of multicast traffic, which with this series means that the vif TXQ will get priority over the others. I think we agreed to fix this by just adding an airtime v_t to the vif as well and use that for scheduling the TXQ. Does ath10k report airtime usage for multicast as well, or only for stations? -Toke