From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id CC1653B2A2 for ; Fri, 18 Nov 2016 02:55:28 -0500 (EST) Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id EAE4C338849; Fri, 18 Nov 2016 07:55:27 +0000 (UTC) Received: from localhost (ovpn-200-33.brq.redhat.com [10.40.200.33]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAI7tPdw011067; Fri, 18 Nov 2016 02:55:26 -0500 Date: Fri, 18 Nov 2016 08:55:24 +0100 From: Jesper Dangaard Brouer To: Dave Taht Cc: brouer@redhat.com, make-wifi-fast@lists.bufferbloat.net Message-ID: <20161118085524.62d6cfdd@redhat.com> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 18 Nov 2016 07:55:27 +0000 (UTC) Subject: Re: [Make-wifi-fast] a bit of profiling on the archer X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Nov 2016 07:55:28 -0000 On Thu, 17 Nov 2016 20:14:49 -0800 Dave Taht wrote: > I have not been profiling much on lower end platforms (it's hard, you > can crash a box pretty easily with the wrong options or sample rates). I'm happy to hear that perf does work on this lower end HW, although the disclaimer of sample rates. Does anyone know if hardware based PMU (Performance Monitor Units) exists for these kind of devices? > While watching the ath10k peak at 150-200mbits, at 99% of cpu in > softirq, I spent a bit of time profiling various counters and > statistics. > > for this one (while downloading 12 flows at the same time via flent) > > perf record -F 99 -e cpu-clock -ag -- sleep 10 > > perf report Below perf report is not well suite for email, could you instead provide output from command below: perf report --no-children --stdio --call-graph none > > [[31m 67.81%[[m 0.00% ksoftirqd/0 [kernel.kallsyms] [k] > run_ksoftirqd > | > ---run_ksoftirqd > | > |[[31m--67.61%-- [[m __do_softirq > | | > | |[[31m--66.80%-- [[m net_rx_action > | | | > | | |[[31m--41.07%-- [[m ag71xx_poll > > ... (Looks like you managed to copy-paste the terminal escape codes for colors) > > It appears we're spending 66% of the time in the *ethernet* portion of > the path. Be careful you don't fool yourself. In your output you have the "children" mode on, so everything being called "under" net_rx_action is summed up. It could be it goes all the way through to the wifi TX parts and that is part of the sum. Even the memory allocations gets summed into this 66% number. > I'm going to stop worrying so much about the performance of the new > wifi algorithms. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer