From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x236.google.com (mail-oi0-x236.google.com [IPv6:2607:f8b0:4003:c06::236]) (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 51E803B29E for ; Sun, 26 Aug 2018 21:33:53 -0400 (EDT) Received: by mail-oi0-x236.google.com with SMTP id k12-v6so24531392oiw.8 for ; Sun, 26 Aug 2018 18:33:53 -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=9xldIXYgGTTcSRhTMaR+YY+SRiOw4t7st8v4AArSwqo=; b=jojmbxMpGNW/xRtnHyFWjq+HWuQljx7NWA4ljVtv2NCUM961KhHxbCsa0ztSybw7Lc 57tXp8nJjnlYw4VMHZwrfLutlOOTUrZw/LRnblpbdCDa8BgVXcEnGSI325ncyth8tied JYDjKIjbZxVmNuNiIrWSVb6RLsab45kDEpbPtZnl38njG+lL/ozElkQ//abLaIqz7n2v U5mirEE/aXK72W0UQQTgrQ6vneuea8b40p2mDLsj0ZJdeRcbcTGAv80+tu70vn2LVHSi xGdwPwIkbiWK98Yi7bhCChHGYGA00lf0SLRQzTLOanEYruAJRxq7HbQa3tovg6cwS2TR PeCg== 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=9xldIXYgGTTcSRhTMaR+YY+SRiOw4t7st8v4AArSwqo=; b=GCTVt66gkfWZMxiNKJZMxGewuScJ2j45t3ourkulFnoL3ealZ/DnNwiiHmJE1PhSKJ 7+538Nw2QIyhAcznVR06dk3kZGAkBmVBfKaPcseGO4BOM8TBQcijcfXAsfuNADxwVANZ Y/YHyqPL27cQML2h1VsXiiSm0waZfxdQ0KZP/u+7eUTIHcUWG6Jy+Xw8yDSeMoLPQbX5 Am16kop4Ysyfi4Rih8VUJTMRW0LPluuBx81V138lZh6INnBXdxdovCllYYqBWw6Osm9x gokunA9Ao/V5ISlVatIYVRl0P4S+vV3yHckaG4uWDtszNgm+2YTd26FhYmKQg8D9taLB 5HjQ== X-Gm-Message-State: APzg51BCYsTMy2p73MeRL32VFWaBxH1f4kemJn++HjwoEROd2vtkNmiH 0pdkVkkSdf+Z0CMojeJ6R+5PdTvr4qmTLAAncSI= X-Google-Smtp-Source: ANB0VdZqPCgeYgtBkebMWxLPBk0ZEyXCWthC3TxIIdwhGEnvfppOIeSGDqpsLt5vThAR66w72xKjdv3jas0/8IkcfQQ= X-Received: by 2002:aca:72cf:: with SMTP id p198-v6mr10904921oic.141.1535333632643; Sun, 26 Aug 2018 18:33:52 -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: Rosen Penev Date: Sun, 26 Aug 2018 18:33:45 -0700 Message-ID: To: Dave Taht 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 01:33:53 -0000 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 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= ARM > > > > > > Cortex A53 processor up to 1.2GHz" - how does that compare? I h= ave > > > > > > plenty of ath10k and ath9k pcmcia cards.... > > > > > > > > > > I have one of these, incl wifi. Right now the drivers are not in = great > > > > > shape, but they're being worked on. My espressobin has worse perf= ormance > > > > > 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= /commit/drivers/net/ethernet/marvell/mvneta.c?h=3Dnext-20180824&id=3D0f5c6c= 30a0f8c629b92ecdaef61b315c43fde10a > > > > > > I was on that thread. It was broken before entirely. As for the singl= e > > > 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 lot= s > > > of different interrupt types... and (fantasizing again) I'd love it i= f > > > we had a scratchpad or dedicated memory to store interrupt handlers i= n > > > 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 o= n 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. > > > > > > > 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 har= d > > > to correctly measure interrupt latency regardless. > > > > > > > > > > > > > > > > I have talked to people who say the drivers are being worked on t= hough... > > > > > If you have input, Kaloz is probably a great person to take that = 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