From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x22a.google.com (mail-qt0-x22a.google.com [IPv6:2607:f8b0:400d:c0d::22a]) (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 923603B29E for ; Sun, 26 Aug 2018 21:45:23 -0400 (EDT) Received: by mail-qt0-x22a.google.com with SMTP id t39-v6so15549818qtc.8 for ; Sun, 26 Aug 2018 18:45:23 -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=YYW5jbXzmKRz8/Obr82dL+VimAJ6S1tkqq/H0CfqSeg=; b=fCgHEUD8Ul1GGn/7SMf2A9KE29tLAvRn0+povc4KAOesxG/j7W7lbHpa6mvP/by22x MjsUA/VxbkuS2r+wqqHMIMExpFEi8h09vt5+i90PhW5wee5WshToWyc1JC2n0XENY/0J 0ieizAWxqJAT86KC3B6ZXKN3vtmS1I+GiHGL/yFuBCMI0NUwoZsdaMyTcbjV0OlPiGJC SeDboHTawq2zDWv2qGq1qYOQ0kElJfxbgKwNhnPRWTYxrMfJuFzcF2IEzDrscmzLXKTi SSZ6hdqaeBirdC9gaN3chVoPR6wPaLGicLL+JbFGlxo4uy+7wuyzBnyNS885Kl6aI3U7 UZNQ== 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=YYW5jbXzmKRz8/Obr82dL+VimAJ6S1tkqq/H0CfqSeg=; b=mNRFTTyZLghIKCjKOtFZHr/udwcWlDMqt4EReuKyve246dMwGELnyNXGmFnUsfnOjZ bUbns0djU1GX/puPjjJQ4Y/JCg1ywfVhusjLgMsH30h0gFXi6rBy2R6bD03gHpin8Gye qGffHy5rLQlGpELkOR0ZruyTIZ3rQ5fZYqpRTAotiYhQZ/a7Y84zQaPJWFGTsua/dDgI TYQPwh1nd1Djm5BiHOSUb1l8XMMPwR4hFOcFh8C2eHNv6/YhocPppKUQhieiarDZLar8 NDHc/XzCHMv2QH1QaYMhEwzT5SuPjqsHioCu6MIsNrnUvdxdatTzthgTozUl3MhTy9jG zuvQ== X-Gm-Message-State: APzg51BDZpDl4qaXzM+adb2qwf1TixQxDCYVtsTc8xSVf4Dwjb62qSvq +ICR1iiWT3Lf6IYmDUehW4sakN0TlKJp0m575ew= X-Google-Smtp-Source: ANB0VdZZxLdzuguJDFiI9zlL07CaqVtbGnlljEmu1aMY7cU+/hODk8o+fyfVDoyi67MeR59W0fKM8u8pSiva/4q0OCg= X-Received: by 2002:ac8:2e87:: with SMTP id h7-v6mr3104167qta.135.1535334323093; Sun, 26 Aug 2018 18:45:23 -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 18:45:11 -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 01:45:23 -0000 On Sun, Aug 26, 2018 at 6:33 PM Rosen Penev wrote: > > On Sun, Aug 26, 2018 at 6:20 PM Dave Taht wrote: > > > > 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 wrot= e: > > > > > > > > > > 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 co= re ARM > > > > > > > Cortex A53 processor up to 1.2GHz" - how does that compare? I= have > > > > > > > plenty of ath10k and ath9k pcmcia cards.... > > > > > > > > > > > > I have one of these, incl wifi. Right now the drivers are not i= n great > > > > > > shape, but they're being worked on. My espressobin has worse pe= rformance > > > > > > 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.g= it/commit/drivers/net/ethernet/marvell/mvneta.c?h=3Dnext-20180824&id=3D0f5c= 6c30a0f8c629b92ecdaef61b315c43fde10a > > > > > > > > I was on that thread. It was broken before entirely. As for the sin= gle > > > > 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 l= ots > > > > 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 NAP= I > > > > 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. > No. Definitely not enough. > > > > 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? > Yeah I did. Felix rejected it on the grounds that he didn't understand > it. So I've just been keeping it in my tree. The patch itself comes > from an old SDK by Qualcomm. Hmm. By eyeball I can't see how it could speed up things that much either. = :) But I used to be willig to bnchmark. not thi month though > > > > > > > > > > > > It's kind of unfortunate given how much atheros hardware is out there= . > > > > > > > > Given something *cool* now landing ( skb list batching, see lwn ) i= t > > > > 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 ri= p > > > > the latency out of stuff, they'd rather add features. It's really h= ard > > > > to correctly measure interrupt latency regardless. > > > > > > > > > > > > > > > > > > > > I have talked to people who say the drivers are being worked on= though... > > > > > > If you have input, Kaloz is probably a great person to take tha= t input. 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 > > > > > > > > -- > > > > 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