From owner-freebsd-net@freebsd.org Wed Aug 17 15:38:40 2016 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 9646DBBC6C0 for ; Wed, 17 Aug 2016 15:38:40 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-it0-x234.google.com (mail-it0-x234.google.com [IPv6:2607:f8b0:4001:c0b::234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5B8DD1663 for ; Wed, 17 Aug 2016 15:38:40 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: by mail-it0-x234.google.com with SMTP id e63so2919039ith.1 for ; Wed, 17 Aug 2016 08:38:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=SDaLpOiFJfbX7V6nJZgkryEZkULJ0wU5ceHj74PJQdg=; b=G/RaZpnM0EqX3tT7GVdVv/SeavGeyHKu9XzuMfcISxqds3XifoHAyT/gGafbmmfYFh bgpaFQVLlbzBZF8gfp1iyXmeXsj6uVEiQZzozB7h6zRst4n0FZqGMs+v0ZoPn8xA3HFu ngcQoGXzoK27VUtdWZlO2eFO8yicknThA/4vM88y4QTvWr0AU/7XrF48gjQX0oUVbda2 OxU9hYD2w9P6Fa854OzUJhkAEChCDiEQau0ZE+gvMv1P2UoRCWZvZv2d/hye4P3RLUpL NmndFzizWmP+rEcorun+EQUldVG9Q4mm8A2oR/poKZ0bQRvIF63K0WOJwNdX5j0liTWV tWEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=SDaLpOiFJfbX7V6nJZgkryEZkULJ0wU5ceHj74PJQdg=; b=G3Sn29sDLXQyA4O0bdxWr5MA5AvXko0qjSmV0IozDC4ldRbUcXmcKkThXCCn5K6bvJ S28A/AyJzKmdS5Gl0i5ueqKwa4IqrxyoR2voHU+YBEeDtm6X44o0CFv+Gir5HqAPGwcw M61r4miDB0Sm52wLSETCYsmbKVAkF3hbaguUkQy4BKq5n2QSFPrt6gCFGU1/y/x/cjW3 Z86jdHrchHsOFBxXIeOtHM3SYS5Q4uLE/hhK4UljmwVTCgjU3ZCqvARL7vmgcs3138B2 xDGVZec3xVES+QDnV8L0T6TWZ96SaqAQZf8s73vRXhSjzod+BDw1KZKvWqfSZ+7apIyz zLvw== X-Gm-Message-State: AEkooutEUu2+MOg60Xn/ZVxlzgX8PruuyJmI5WqdBHG/CaQGgD77v5UY1pbAQlLcCwIyw1izcZaYbz6gHFbpRA== X-Received: by 10.36.242.68 with SMTP id j65mr27792893ith.25.1471448319720; Wed, 17 Aug 2016 08:38:39 -0700 (PDT) MIME-Version: 1.0 Received: by 10.36.141.129 with HTTP; Wed, 17 Aug 2016 08:38:38 -0700 (PDT) In-Reply-To: References: <3C0D892F-2BE8-4650-B9FC-93C8EE0443E1@gmail.com> <3B164B7B-CBFB-4518-B57D-A96EABB71647@gmail.com> <5D6DF8EA-D9AA-4617-8561-2D7E22A738C3@gmail.com> <7DD30CE7-32E6-4D26-91D4-C1D4F2319655@gmail.com> <91AEB1BD-44EA-43AD-A9A1-6DEBF367DF9B@gmail.com> From: Adrian Chadd Date: Wed, 17 Aug 2016 08:38:38 -0700 Message-ID: Subject: Re: Unstable local network throughput To: Ben RUBSON Cc: FreeBSD Net Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Aug 2016 15:38:40 -0000 [snip] ok, so this is what I was seeing when I was working on this stuff last. The big abusers are: * so_snd lock, for TX'ing producer/consumer socket data * tcp stack pcb locking (which rss tries to work around, but it again doesn't help producer/consumer locking, only multiple sockets) * for some of the workloads, the scheduler spinlocks are pretty heavily contended and that's likely worth digging into. Thanks! I'll go try this on a couple of boxes I have with intel/chelsio 40g hardware in it and see if I can reproduce it. (My test boxes have the 40g NICs in NUMA domain 1...) -adrian