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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 97212C433E0 for ; Thu, 11 Mar 2021 14:59:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 548AF64DDA for ; Thu, 11 Mar 2021 14:59:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233970AbhCKO7N (ORCPT ); Thu, 11 Mar 2021 09:59:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233962AbhCKO6p (ORCPT ); Thu, 11 Mar 2021 09:58:45 -0500 Received: from mail-lf1-x130.google.com (mail-lf1-x130.google.com [IPv6:2a00:1450:4864:20::130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B202C061574 for ; Thu, 11 Mar 2021 06:58:44 -0800 (PST) Received: by mail-lf1-x130.google.com with SMTP id q25so40217402lfc.8 for ; Thu, 11 Mar 2021 06:58:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=austral-dynamics-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :content-transfer-encoding; bh=oQ4gNlA29uLYaqukVepQ7MZospwRrQxunXXR/K/Cb90=; b=iT8dCIoQpMOQKjqu3vLqiQ/yWsBGBNwxjSPxG7d5KrnFCJdnlvpxZjGbWC8ZFkmrAC Z3Yf74Xoke22Y70uPXeMjVqpOQCZ8LFmUnMbTdqXxymSumdpO00m6klb0xsMt2Q/s1t9 LgO5TTEq4jZnpd8nw2CxjVDjWdnSV/ry9N5w34FhW2/ENflwYkqqcveMLaW4IHQV3fU1 NVkn/IFNsLZAXvH8XoD3PZpLw/nd8gyKi2ETjIUnVEpwkxGLADwFL6FrIkau4/kVITMH yT3WTkopCu1jcnUw4Sy9jPw7g7Wei3W9N8BAy4fTKSfuDi6E2kBmFYM0nkeouRXDSJQ/ Rt2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:content-transfer-encoding; bh=oQ4gNlA29uLYaqukVepQ7MZospwRrQxunXXR/K/Cb90=; b=S/PHKUZ5sV9nW6GJnPw2Ed16Zeb7OnsNsjgLHw87nY1iUMis0YD3q6H8PU0RrtVVHr Glk1S1r4L/0rv3KJT/zLRGJH5Hf6FVsIce5OT0zKDSI/eKOUZDHVb6z3y3Kxs2bAhKij x6fsamNFOqT6/0AvxyBmi9S6bs3QieUCdgI35+yXZ1pVNUDOuGPYIRqGfGrR1ik5OSXb 0ewjiChtCuagCTg7fvPmhuGj+14yHb0gjIFLyytzAdJl1KnMaVRYNo4fofgpaNBT8CdC fwKzw/K5C+cli68sXw0A2ISJ7MSXhzzJHNevlxEwuiuRSethMAohrdp62blf/zG/xmnQ k2IQ== X-Gm-Message-State: AOAM5332XCcnG8nvI16yAz3gy1Itl5H/UDiq2h1FHUSIVe2vzT8QDmZr wJAIMO1oS6gIyCCy5TvXn4/DUvvuSxCLNsFgvo8+4FFktfQyQg== X-Google-Smtp-Source: ABdhPJxxm9BOUr1rIzHxpiAMbdhDQnhBuBxtl884CLwpjV8gFmRgdZUMJ/J0ITkYfnLmK7FzqQ1BsueDIZ0GdmtcdEo= X-Received: by 2002:a05:6512:2212:: with SMTP id h18mr2508180lfu.330.1615474722875; Thu, 11 Mar 2021 06:58:42 -0800 (PST) MIME-Version: 1.0 References: <9be68ca5-9fec-161c-1b37-1b47c0a1d845@monom.org> In-Reply-To: <9be68ca5-9fec-161c-1b37-1b47c0a1d845@monom.org> From: Michel Macena Oliveira Date: Thu, 11 Mar 2021 11:56:50 -0300 Message-ID: Subject: Re: PREEMPT_RT benchmark To: Daniel Wagner , linux-rt-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org Hi Daniel, Thanks for your answer! That was the problem! If I understand correctly when Cyclictest writes to the cpu_dma_latency file, the processor does not sleep and remain full power all the time. Is there any problem writing a RT application (not a benchmark one) with this trick? Could it cause any harm to the system? My idea is to develop a RT application in which I have a scheduled thread to compute and deliver results in a given time or interval. Michel Em qui., 11 de mar. de 2021 =C3=A0s 09:27, Daniel Wagner e= screveu: > > Hi Michel, > > On 10.03.21 21:07, Michel Macena Oliveira wrote: > > At least that's what I expected, but my latencies are much bigger than > > Cyclictest ones. > > From cyclictest I get an average in my computer of something between > > 2300 and 2500 nanoseconds. However, in my application I'm having > > something between 47000 and 55000 nanoseconds. As you can see it is > > much higher! > > > > I'm not sure of what I'm doing wrong, could you help or suggest somethi= ng? > > Check if your system uses power managment. cyclictest disables the power > management by using the /dev/cpu_dma_latency API. > > HTH, > Daniel