From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH] arm64: hikey960: update idle-states Date: Fri, 6 Jul 2018 09:59:15 +0200 Message-ID: <722aed2b-673b-7f17-2337-a7b3442dca56@linaro.org> References: <1530860246-29072-1-git-send-email-vincent.guittot@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1530860246-29072-1-git-send-email-vincent.guittot@linaro.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Vincent Guittot , xuwei5@hisilicon.com, robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: leo.yan@linaro.org List-Id: devicetree@vger.kernel.org On 06/07/2018 08:57, Vincent Guittot wrote: > Update entry/exit latency and residency time of hikey960 to use more > realistic figures based on unitary tests done on the platform. > > The complete results (in us) : > big cluster > cluster CPU > max entry latency 800 400 > max exit latency 2900 550 > residency 903Mhz 5000 1500 > residency 2363Mhz 0 1500 > > little cluster > cluster CPU > max entry latency 500 400 > max exit latency 1600 650 > residency 533Mhz 8000 4500 > residency 1844Mhz 0 1500 > > We can see that the residency time depends of the running OPP which is not > handled for now. Then we also have to take into account the constraint of > a residency time shorter than the tick to get full advantage of idle loop > reordering(tick is stopped if idle duration is higher than tick period). > Finally the selected residency value are : > big cluster > cluster CPU > residency 3700 1500 > > little cluster > cluster CPU > residency 3500 1500 > > A simple test with a task waking up every 11,111ms shows improvement: > - 5% a lowest OPP > - 22% at highest OPP > > The period has been chosen: > - to be shorter than old cluster residency time and longer than new > residency time od cluster off C-state > - to prevent any sync with tick (4ms) when running tests that can add > some variances between tests > > Signed-off-by: Vincent Guittot > --- Great! Thanks for fixing the values. Acked-by: Daniel Lezcano -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog