From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x22d.google.com (mail-qt0-x22d.google.com [IPv6:2607:f8b0:400d:c0d::22d]) (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 849363B29E for ; Sun, 26 Aug 2018 21:20:06 -0400 (EDT) Received: by mail-qt0-x22d.google.com with SMTP id f19-v6so14868138qtf.2 for ; Sun, 26 Aug 2018 18:20:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=pukNbq3QMxkRuMxYMK4iqOkW3hNWcgnCo5GGLbbmp7k=; b=EotW9sZgsO7cuk6QLcwRyizOpW0Ai8R32LtIWGwTdd4RygVjQn0VBH2cBsytJzpfGq wKysn5i4jaVFtnEnKlURRgY0QO69cz+lirhbEUeLex2LsNDcUecjPbOUITcOnDBZDbUM kDjfoXbEhliTBZtV6Yh6vp5EleCfTU5YYVlzDYd+cJROnD1O4QsEj7uQwbw/OLsKdi3O Ukt8MyBGKBfIPQ21FbZ4dVJje+y/+G992UcximRbuqReOiQTojJUxcCXdurgHcGPQjUS M5xHtjvxb4i5w7gQ8Qkzk78t5wO5uWmXJoJKlh4mHsgdelGMyNEzOHT4ZBVmNRNtDyfn idig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=pukNbq3QMxkRuMxYMK4iqOkW3hNWcgnCo5GGLbbmp7k=; b=STNVY7uPSYpK4mn7y8z6TV2sa30PXEdmtRjALY18lj43LnJ5qGD3Jimi4OVWWo3aLR AJzC/kSeY1/ShTDfMtF/2ATR7Y8M4gvIUdsAAqPzbPisQKqKhOOL28yljc6Crd5Ffvqg aGvciz+AXQL2V8StG2SkhHAkeB7jzv+3zIyhLVLoBnfdCuqd+p6APpNC8oN9dHf/Ce3g suqI/Lo/ickfQqNEpkYc7VLvOs1QaLF+nVmzb/1W5Fact0hDHRIP3Iw+e/yF64kxOoHh bgK1tI1oXz+lo9Wb536gLg4GYHAWbhP0Xu8iN8JmzBj1y5dWNYEMwyF27s1wpu0IraLd jkLQ== X-Gm-Message-State: APzg51AxXC4GRUXxAJA1/8hJXfMc08pZfjs1WES6yDz9vqP5B5tLZpkc f9q57mkN3nrGi3Uh2Xpmux5itlV39066ceKBw+E= X-Google-Smtp-Source: ANB0VdYoucpO6EUnl62mswbfq2MDS7gVAabtgo8+zVhss8sODF393y8z+byRYfWbFG6MKIHaGocSw9o8fwQvhBDCT7I= X-Received: by 2002:ac8:1e97:: with SMTP id c23-v6mr11901011qtm.298.1535332806032; Sun, 26 Aug 2018 18:20:06 -0700 (PDT) MIME-Version: 1.0 References: <66e2374b-f998-b132-410e-46c9089bb06b@gmail.com> <360212B1-8411-4ED0-877A-92E59070F518@gmx.de> In-Reply-To: From: Dave Taht Date: Sun, 26 Aug 2018 18:21:46 -0700 Message-ID: To: Rosen Penev Cc: Mikael Abrahamsson , bloat Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Bloat] Marvell 385 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: Mon, 27 Aug 2018 01:20:06 -0000 On Sun, Aug 26, 2018 at 5:55 PM Rosen Penev wrote: > > On Sun, Aug 26, 2018 at 2:09 PM Dave Taht wrote: > > > > On Sun, Aug 26, 2018 at 1:58 PM Rosen Penev wrote: > > > > > > On Sun, Aug 26, 2018 at 11:44 AM Mikael Abrahamsson wrote: > > > > > > > > On Sat, 25 Aug 2018, Dave Taht wrote: > > > > > > > > > The expressobin is a Marvell Armada "3700LP (88F3720) dual core A= RM > > > > > Cortex A53 processor up to 1.2GHz" - how does that compare? I hav= e > > > > > plenty of ath10k and ath9k pcmcia cards.... > > > > > > > > I have one of these, incl wifi. Right now the drivers are not in gr= eat > > > > shape, but they're being worked on. My espressobin has worse perfor= mance > > > > than on its wired ports than my WRT1200AC (Armada 385). > > > If as you mentioned earlier that ethernet performance is limited by > > > interrupts, then this commit is kind of depressing: > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/c= ommit/drivers/net/ethernet/marvell/mvneta.c?h=3Dnext-20180824&id=3D0f5c6c30= a0f8c629b92ecdaef61b315c43fde10a > > > > I was on that thread. It was broken before entirely. As for the single > > interrupt on this chip variant - believe it or not, I'm not huge on > > lots of different interrupts for everything. I'd like it if we had > > more than an rx or tx interrupt > > in general, I'd love it if we had a programmable "tx is almost done" > > interrupt that you could tune to the > > interrupt latency... and it's complicated and costs wires to have lots > > of different interrupt types... and (fantasizing again) I'd love it if > > we had a scratchpad or dedicated memory to store interrupt handlers in > > rather than relying on cache.... > > > > I'd looked deeply into improving this driver once upon a time, and > > wanted to rip the software gro out of it, > > in particular, and not defer things as much, trying things like NAPI > > of 16 and measuring where time was spent. The copy to memory is > > expensive, and then it defers further work. > > > > Less code, particularly near interrupt time, is better than a lot. > > adding XMIT_MORE to the ar71xx driver (which hurt it badly) is one > > example. > I've been looking a lot at ag71xx. The driver has so much low hanging > fruit. Unfortunately I lack the knowledge to fix most of it. > > This patch for example gives me a ~20-30mbps improvement in iperf > tests: https://pastebin.com/ZExWjXQZ cool! that driver as widely used as it is has never had enough eyeballs on = it. Have you put that patch in front of the openwrt folk? I note that that driver didn't used to live in that part of the tree - have they finally moved over? > > It's kind of unfortunate given how much atheros hardware is out there. > > > > Given something *cool* now landing ( skb list batching, see lwn ) it > > would be worthwhile to revisit this. I don't care if I get more > > interrupts/sec (particularly on a multicore) if we could drain the rx > > ring over smaller intervals... > > > > but that's me, I'm all about the latency. :) Nobody's willing to rip > > the latency out of stuff, they'd rather add features. It's really hard > > to correctly measure interrupt latency regardless. > > > > > > > > > > > > I have talked to people who say the drivers are being worked on tho= ugh... > > > > If you have input, Kaloz is probably a great person to take that in= put. I > > > > know other people working on Marvell drivers as well. > > > > > > > > -- > > > > Mikael Abrahamsson email: swmike@swm.pp.se > > > > _______________________________________________ > > > > Bloat mailing list > > > > Bloat@lists.bufferbloat.net > > > > https://lists.bufferbloat.net/listinfo/bloat > > > > > > > > -- > > > > Dave T=C3=A4ht > > CEO, TekLibre, LLC > > http://www.teklibre.com > > Tel: 1-669-226-2619 --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619