From owner-freebsd-arch@FreeBSD.ORG Thu Aug 25 16:24:50 2011 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8A051106564A for ; Thu, 25 Aug 2011 16:24:50 +0000 (UTC) (envelope-from bf1783@googlemail.com) Received: from mail-ey0-f172.google.com (mail-ey0-f172.google.com [209.85.215.172]) by mx1.freebsd.org (Postfix) with ESMTP id 23DDD8FC0A for ; Thu, 25 Aug 2011 16:24:49 +0000 (UTC) Received: by eye4 with SMTP id 4so1601092eye.31 for ; Thu, 25 Aug 2011 09:24:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=mime-version:reply-to:in-reply-to:references:date:message-id :subject:from:to:content-type; bh=x7VYpgLh0wyUcaXij2fGsRM7JxnLVqjrOnKG8BqEw5A=; b=Mb+ryDNHt+44G5yFfVL7udHQ0yvf8kn6kwJBXF3gn7Y20LqoD0BGgV7OFlMf00fdV3 lSFMZAkTx7HeZpepd5TjCuBimPkqOIVN+MpozoDnMyDzKGqM6J4BHh+CKUBmkxILD/Rz t+c/Sfv6nxSRbna1fsiRnB8Kk21X7C6VImXVs= MIME-Version: 1.0 Received: by 10.142.141.11 with SMTP id o11mr1829347wfd.56.1314287884464; Thu, 25 Aug 2011 08:58:04 -0700 (PDT) Received: by 10.68.66.106 with HTTP; Thu, 25 Aug 2011 08:58:04 -0700 (PDT) In-Reply-To: References: Date: Thu, 25 Aug 2011 15:58:04 +0000 Message-ID: From: "b. f." To: freebsd-arch@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Subject: Re: Updating our TCP and socket sysctl values... X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: bf1783@gmail.com List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Aug 2011 16:24:50 -0000 On 8/25/11, b. f. wrote: >> >> I believe it's time to up these values to something that's in line with >> >> higher speed >> >> local networks, such as 10G. Perhaps it's time to move these to 2MB >> >> instead of 256K. >> >> >> >> Thoughts? >> > >> > >> > This never happened, did it? Was there a reason? >> > >> >> I went back and looked at the mail thread. I didn't see any strong >> objections >> so I think you should commit this for 9.x. >> >> np@ did point out that nmbclusters also lags on modern hardware so >> consider upping >> that at the same time. > > I thought Bruce's observation, in: > > http://lists.freebsd.org/pipermail/freebsd-arch/2011-March/011193.html > > that: > > "...there is an mostly-unrelated bufferbloat problem that is > purely local. If you have a buffer that is larger than an Ln cache (or > about half than), then actually using just a single buffer of that size > guarantees thrashing of the Ln cache, so that almost every memory access > is an Ln cache miss. Even with current hardware, a buffer of size 256K > will thrash most L1 caches and a buffer of size a few MB will thrash most > L2 caches." > > , and his suggestion for some sort of auto-tuning, deserve > consideration. Are you going to address this problem (at least the L2 > and higher cache thrashing), or give some suggestions for tuning in > UPDATING and the relevant manpages? Sorry, I should have sent this to -arch instead of -current. b.