From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752197AbeBBV0f (ORCPT ); Fri, 2 Feb 2018 16:26:35 -0500 Received: from mail-pl0-f49.google.com ([209.85.160.49]:42695 "EHLO mail-pl0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751878AbeBBV01 (ORCPT ); Fri, 2 Feb 2018 16:26:27 -0500 X-Google-Smtp-Source: AH8x226RTRSWmlC963oAXtPbwhjWcb3kTQNoZ2XC1HJoAeNUsJPqLvocIeUjK37rd+gJrMyyArO36g== Subject: Re: [PATCH] of: cache phandle nodes to decrease cost of of_find_node_by_phandle() To: Chintan Pandya , Rob Herring Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <1517429142-25727-1-git-send-email-frowand.list@gmail.com> <5b84a166-c71b-3a41-9e7f-a7624a8441f6@codeaurora.org> <38cdcae5-ec0f-d1be-b024-1990d4387731@gmail.com> <9e23d32f-05a0-ce8a-41f8-9a1a3d66be37@codeaurora.org> <567731e8-8f89-bd6e-c3d4-e36400e69198@codeaurora.org> From: Frank Rowand Message-ID: <0db129ef-ffd8-96fe-46a7-55fb575272e3@gmail.com> Date: Fri, 2 Feb 2018 13:26:25 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <567731e8-8f89-bd6e-c3d4-e36400e69198@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/01/18 21:59, Chintan Pandya wrote: > > > On 2/2/2018 12:40 AM, Frank Rowand wrote: >> On 02/01/18 02:31, Chintan Pandya wrote: >>> >>>>> Anyways, will fix this locally and share test results. >>>> >>>> Thanks, I look forward to the results. >>>> >>> >>> Set up for this time was slightly different. So, taken all the numbers again. >>> >>> Boot to shell time (in ms): Experiment 2 >>> [1] Base            : 14.843805 14.784842 14.842338 >>> [2] 64 sized fixed cache    : 14.189292 14.200003 14.266711 >>> [3] Dynamic freeable cache    : 14.112412 14.064772 14.036052 >>> >>> So, [3] (this patch) looks to be improving 750ms (on avg from base build). >>> >> >> Is this with the many debug options enabled?  If so, can you repeat with >> a normal configuration? > > Could you share me the point of doing this experiment in perf mode ? You had mentioned earlier in another thread: My recent results were taken on debug_defconfig which has many performance slowing code. So, gap between base-build and w/ the test patches would be more than the actual production build. If you measure a large performance gain with a debug configuration, that may not represent the actual gain you will get with a production configuration, as you noted. My question was trying to determine whether the numbers reported above are for a debug configuration or a production configuration. And if not a production configuration, I was requesting the numbers for a production configuration. If the production configuration does not show a significant boot time reduction from the patch then there is less justification for adding complexity to the existing code. I prefer to use simpler data structures and algorithms __if__ extra complexity does not provide any advantage. The balance between complexity and benefits is a core software engineering issue. > I don't have a set up for taking these numbers in perf mode. For > that, I need to ask some other team and round trip follow ups. In my > set up, I rely on serial console logging which gets disabled in perf > mode. > >> >> Thanks, >> >> Frank >> > > Chintan