From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <sesse@samfundet.no>
Received: from cassarossa.samfundet.no (cassarossa.samfundet.no
 [IPv6:2001:67c:29f4::29])
 by lists.bufferbloat.net (Postfix) with ESMTPS id 687273B2A0
 for <bloat@lists.bufferbloat.net>; Tue,  5 Jan 2016 19:55:39 -0500 (EST)
Received: from yesthisis.dog
 ([2001:67c:29f4::3007] helo=pannekake.samfundet.no ident=unknown)
 by cassarossa.samfundet.no with esmtps
 (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84)
 (envelope-from <sesse@samfundet.no>)
 id 1aGcO1-00077J-Dw; Wed, 06 Jan 2016 01:55:37 +0100
Received: from sesse by pannekake.samfundet.no with local (Exim 4.84)
 (envelope-from <sesse@samfundet.no>)
 id 1aGcO1-0006DD-9s; Wed, 06 Jan 2016 01:55:37 +0100
Date: Wed, 6 Jan 2016 01:55:37 +0100
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "bloat@lists.bufferbloat.net" <bloat@lists.bufferbloat.net>
Message-ID: <20160106005537.GA20844@sesse.net>
References: <165DB6E9-A6DD-4626-B6AA-E1B2DBA0B5FA@gmail.com>
 <CALQXh-PKLhLC=r3-nGBNq_rUYgDKknsHfxHBu+TsGzLUWCVUSw@mail.gmail.com>
 <CAJq5cE3F37u1AGOO8dvGWkd4y=oqqtiTjZJ_7se+=rygdsW3hw@mail.gmail.com>
 <568C1209.5050403@taht.net>
 <CAJ_ENFHA++fSosEY5RDR=82H5XdkQ8P31Nhksrq7OA_Ds_EBZg@mail.gmail.com>
 <20160106000151.GA5332@sesse.net>
 <CAOaVG17j+SqFy=fSnByNxqQXyfWnage_P7nUL7YE9H_CsXzW7A@mail.gmail.com>
 <20160106002213.GA8486@sesse.net> <20160105165314.118713f3@xeon-e3>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20160105165314.118713f3@xeon-e3>
X-Operating-System: Linux 4.3.0 on a x86_64
User-Agent: Mutt/1.5.23 (2014-03-12)
Subject: Re: [Bloat] Hardware upticks
X-BeenThere: bloat@lists.bufferbloat.net
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: General list for discussing Bufferbloat <bloat.lists.bufferbloat.net>
List-Unsubscribe: <https://lists.bufferbloat.net/options/bloat>,
 <mailto:bloat-request@lists.bufferbloat.net?subject=unsubscribe>
List-Archive: <https://lists.bufferbloat.net/pipermail/bloat>
List-Post: <mailto:bloat@lists.bufferbloat.net>
List-Help: <mailto:bloat-request@lists.bufferbloat.net?subject=help>
List-Subscribe: <https://lists.bufferbloat.net/listinfo/bloat>,
 <mailto:bloat-request@lists.bufferbloat.net?subject=subscribe>
X-List-Received-Date: Wed, 06 Jan 2016 00:55:39 -0000

On Tue, Jan 05, 2016 at 04:53:14PM -0800, Stephen Hemminger wrote:
>> Also, I've never ever seen the actual context switch turn up high in a perf
>> profile.  Is this because of some sampling artifact?
> Yes, especially with Intel processors getting more and more SSE/floating point
> registers.

But those are not saved on context switch to the kernel, no? (Thus the rule
of no floating-point in the kernel.) Only if you switch between userspace
processes.

/* Steinar */
-- 
Homepage: https://www.sesse.net/