From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FE99C433DF for ; Fri, 10 Jul 2020 14:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 354C8207BB for ; Fri, 10 Jul 2020 14:00:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727782AbgGJOAn (ORCPT ); Fri, 10 Jul 2020 10:00:43 -0400 Received: from foss.arm.com ([217.140.110.172]:48346 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726840AbgGJOAn (ORCPT ); Fri, 10 Jul 2020 10:00:43 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CF53F1FB; Fri, 10 Jul 2020 07:00:42 -0700 (PDT) Received: from [10.37.12.58] (unknown [10.37.12.58]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9E75D3F819; Fri, 10 Jul 2020 07:00:39 -0700 (PDT) Subject: Re: [PATCH 1/2] memory: samsung: exynos5422-dmc: Adjust polling interval and uptreshold To: Bartlomiej Zolnierkiewicz Cc: Krzysztof Kozlowski , Chanwoo Choi , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, willy.mh.wolff.ml@gmail.com, k.konieczny@samsung.com, chanwoo@kernel.org, myungjoo.ham@samsung.com, kyungmin.park@samsung.com, s.nawrocki@samsung.com, kgene@kernel.org References: <20200708153420.29484-1-lukasz.luba@arm.com> <20200708153420.29484-2-lukasz.luba@arm.com> <20200710124503.GB22897@pi3> <0bfb4332-9a2e-9ff9-1a86-d9875a8f34bb@arm.com> From: Lukasz Luba Message-ID: Date: Fri, 10 Jul 2020 15:00:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org On 7/10/20 2:49 PM, Bartlomiej Zolnierkiewicz wrote: > > On 7/10/20 2:56 PM, Lukasz Luba wrote: >> >> >> On 7/10/20 1:45 PM, Krzysztof Kozlowski wrote: >>> On Fri, Jul 10, 2020 at 09:34:45AM +0100, Lukasz Luba wrote: >>>> Hi Chanwoo, >>>> >>>> On 7/9/20 5:08 AM, Chanwoo Choi wrote: >>>>> Hi Lukasz, >>>>> >>>>> On 7/9/20 12:34 AM, Lukasz Luba wrote: >>>>>> In order to react faster and make better decisions under some workloads, >>>>>> benchmarking the memory subsystem behavior, adjust the polling interval >>>>>> and upthreshold value used by the simple_ondemand governor. >>>>>> >>>>>> Reported-by: Willy Wolff >>>>>> Signed-off-by: Lukasz Luba >>>>>> --- >>>>>>    drivers/memory/samsung/exynos5422-dmc.c | 4 ++-- >>>>>>    1 file changed, 2 insertions(+), 2 deletions(-) >>>>>> >>>>>> diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c >>>>>> index 93e9c2429c0d..e03ee35f0ab5 100644 >>>>>> --- a/drivers/memory/samsung/exynos5422-dmc.c >>>>>> +++ b/drivers/memory/samsung/exynos5422-dmc.c >>>>>> @@ -1466,10 +1466,10 @@ static int exynos5_dmc_probe(struct platform_device *pdev) >>>>>>             * Setup default thresholds for the devfreq governor. >>>>>>             * The values are chosen based on experiments. >>>>>>             */ >>>>>> -        dmc->gov_data.upthreshold = 30; >>>>>> +        dmc->gov_data.upthreshold = 10; >>>>>>            dmc->gov_data.downdifferential = 5; >>>>>> -        exynos5_dmc_df_profile.polling_ms = 500; >>>>>> +        exynos5_dmc_df_profile.polling_ms = 100; >>>>>>        } >>>>>> >>>>> >>>>> Reviewed-by: Chanwoo Choi >>>>> >>>> >>>> Thank you for the review. Do you think this patch could go through >>>> your tree together with your patches? >>>> >>>> I don't know Krzysztof's opinion about the patch 2/2, but >>>> I would expect, assuming the patch itself is correct, he would >>>> like to take it into his next/dt branch. >>> >>> In the cover letter you mentioned that this is a follow up for the >>> Chanwoo's patchset. But are these patches really depending on it? Can >>> they be picked up independently? >> >> >> They are not heavily dependent on Chanwoo's patches. >> Yes, they can be picked up independently. > > Hmmm, are you sure? In a sense: in two phases (first the Chanwoo's changes land into devfreq, then when Krzysztof prepares his topic branches for arm soc, I assumed Chanwoo's patches are mainline and will be there already). > > Sure, they will apply fine but without Chanwoo's patches won't they > cause the dmc driver to use using polling mode with deferred timer > (unintended/bad behavior) instead of IRQs (current behavior) or > polling mode with delayed timer (future behavior)? I was assuming that it will take longer, when Krzysztof is going to pick patch 2/2, definitely after a while (and it could be also the case for patch 1/1 if Krzysztof was going to take it). I think there is no rush and it can go in two phases. Good point Bartek for clarifying this. I wasn't clear in the messages. Thank you for keeping eye on this. Regards, Lukasz > > Best regards, > -- > Bartlomiej Zolnierkiewicz > Samsung R&D Institute Poland > Samsung Electronics > >> I just wanted to mention that the patch 1/2 was produced on the >> code base which had already applied Chanwoo's patch for DMC. >> If you like to take both 1/2 and 2/2 into your tree, it's good. >> >> Thank you for having a look on this. >> >> Regards, >> Lukasz >> >> >>> >>> The DTS patch must go through arm soc, so I will take it. If it really >>> depends on driver changes, then it has to wait for next release. >>> >>> Best regards, >>> Krzysztof >>> >