From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [IPv6:2001:67c:29f4::29]) by lists.bufferbloat.net (Postfix) with ESMTPS id 5A6023B2E2 for ; Tue, 5 Jan 2016 19:22:17 -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 ) id 1aGbri-0002pL-1h; Wed, 06 Jan 2016 01:22:14 +0100 Received: from sesse by pannekake.samfundet.no with local (Exim 4.84) (envelope-from ) id 1aGbrh-0003Ns-PM; Wed, 06 Jan 2016 01:22:13 +0100 Date: Wed, 6 Jan 2016 01:22:13 +0100 From: "Steinar H. Gunderson" To: Stephen Hemminger Cc: "bloat@lists.bufferbloat.net" Message-ID: <20160106002213.GA8486@sesse.net> References: <165DB6E9-A6DD-4626-B6AA-E1B2DBA0B5FA@gmail.com> <568C1209.5050403@taht.net> <20160106000151.GA5332@sesse.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Jan 2016 00:22:18 -0000 On Tue, Jan 05, 2016 at 04:06:03PM -0800, Stephen Hemminger wrote: > The expensive part is often having to save and restore all the state in > registers and other bits on context switch. Are you sure? There's not really all that much state to save, and all I've been taught before says the opposite. Also, I've never ever seen the actual context switch turn up high in a perf profile. Is this because of some sampling artifact? /* Steinar */ -- Homepage: https://www.sesse.net/