From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [IPv6:2001:470:dc45:1000::1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 185BA3B2A2 for ; Fri, 18 Nov 2016 05:26:43 -0500 (EST) Received: from mail.toke.dk (localhost.localdomain [127.0.0.1]) by mail.toke.dk (Postfix) with ESMTPS id A0559117231; Fri, 18 Nov 2016 11:26:41 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1479464801; bh=89sephv9Fe+XJv2PkpjJrVuVAt3+LCzD17ga8QJSLNc=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=OlTKZI0PHEUf2Nqi8RHolp4EOytfAgnhQDJ9OpItJAxuOIzlBfFa6YMh/8aY2BWok CSO4PzyE/e/J0VwDCf9K5KbxIms/szVtvBcv+/+2SiE/JOITtd+961a8S/BKzNqPv4 taYLHmMWy08IGWf9YPpkS4DFQtKd1hQWZIOwcpIucjuJ2vNuoCl92tjGzRvZwF5xBG oDOZFLpCtDQ1PBFIyU8fEzRPaAX8kBcNvh/R5cLnFhUp1WL1xm3hQRtugH5EURXUSV Aug5Vwkvd408aaA0RFX9Dx84WQXdYx0ekcd3D6ap6PJEg0oKBsI4V1CLwryPda1iDy t2kW1unxRR2Jw== Received: by alrua-karlstad.karlstad.toke.dk (Postfix, from userid 1000) id 9C21A92CD51; Fri, 18 Nov 2016 11:26:39 +0100 (CET) From: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= To: Jesper Dangaard Brouer Cc: Dave Taht , make-wifi-fast@lists.bufferbloat.net References: <20161118085524.62d6cfdd@redhat.com> Date: Fri, 18 Nov 2016 11:26:39 +0100 In-Reply-To: <20161118085524.62d6cfdd@redhat.com> (Jesper Dangaard Brouer's message of "Fri, 18 Nov 2016 08:55:24 +0100") X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87zikxw0bk.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain 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 10:26:43 -0000 Jesper Dangaard Brouer writes: > 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. Yes, actually my guess would be that this is the case. When I was profiling ath9k I saw this exact behaviour. -Toke