From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x236.google.com (mail-qt0-x236.google.com [IPv6:2607:f8b0:400d:c0d::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 7B8A43B29E for ; Sun, 26 Aug 2018 17:09:07 -0400 (EDT) Received: by mail-qt0-x236.google.com with SMTP id g44-v6so15209104qtb.12 for ; Sun, 26 Aug 2018 14:09:07 -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=z7CDj23B5RjDLykKXiNmAkVYlpejSIH9u40i1WO8qTI=; b=dIwvArTPP9DhSKqasq3v4rl8gmitRxLt4N08B9fe+CJ1jrTRUX7SRbHA8WEBO1g5eB 6fczAZi9UIpzpQQCeBV037zW7jVlMI6UreH0rXTvp+8x2UNHvCfImRGR5c0Ti2UNQMwq E8z9HyyAE8D/MgKFi4NAyA7DQd0+IpwDzgLanR1lY0PeQzxxoTVNIuX3ABXXLNukF6yB mN57E3fpW0NycDtaA1nrjgbAhw4n4CcR2VIU+wGHdnhOR062H2LMbaYJ/4WPlS7Sh7C/ JCS38sBwdHJIRPhMDVDdNjXUfNmQOtgQxWfaZsyP/BlRN/qCZYQK8aRgWwX1p99qO6DG nwbQ== 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=z7CDj23B5RjDLykKXiNmAkVYlpejSIH9u40i1WO8qTI=; b=lBESqppxQ15bHX/lzXWiWkf/WJrmDlYfYcg/ImfXXqGkqXHAqYqcmzK/VCZZr5/SwP WkHb+pjoZNExFOkDCmi7W64gyxiRiTfX4ughY2/WKLdMfa5ZTysKzVWDiEwN+LS9BBno GRUEPZQ4c310gGXhEn+zjHxKc9u4/HvFBQL7cG6WtbjHy00cLAgrjxDfTFRDccYlum1U XXDV2ECt2ydD/cQROzkawQMPAqXZ5pLfqf3u66V9jWBV9I9JApb4BTUp1un2uKFNrXvU 2mdclbXfwQBAuD2R8pxiVPgwAE8MWCR+yshtDr4OMe4wbMhOBRO3GYRtEo4Jc2RAPnH3 1Kfg== X-Gm-Message-State: APzg51CXFhrO1cCk/Q4p5xp75lDW4WS+buj+rDRPpyAWVAStnj61bSMM 0sljfi4fCck8lMhj9f8VDKcIn3mm7YDMloyk69Y= X-Google-Smtp-Source: ANB0VdbgqsAplWOBwZLbPjY7lT8bax8WcpyW/iKqfK+nJV+DS9ohfgvVw+YTJwGHB/gLS8T8Q+NQBOH4qs1PLrmdtLU= X-Received: by 2002:a0c:bb95:: with SMTP id i21-v6mr11144697qvg.158.1535317747035; Sun, 26 Aug 2018 14:09:07 -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 14:08:55 -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: Sun, 26 Aug 2018 21:09:07 -0000 On Sun, Aug 26, 2018 at 1:58 PM Rosen Penev wrote: > > On Sun, Aug 26, 2018 at 11:44 AM Mikael Abrahamsson wr= ote: > > > > 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 have > > > 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 performanc= e > > 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/commi= t/drivers/net/ethernet/marvell/mvneta.c?h=3Dnext-20180824&id=3D0f5c6c30a0f8= c629b92ecdaef61b315c43fde10a 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. 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 though.= .. > > 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 --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619