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=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 11517C48BE5 for ; Mon, 21 Jun 2021 05:36:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D07EF61059 for ; Mon, 21 Jun 2021 05:36:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229651AbhFUFiS (ORCPT ); Mon, 21 Jun 2021 01:38:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:46128 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229487AbhFUFiQ (ORCPT ); Mon, 21 Jun 2021 01:38:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624253762; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RY9DMg40/fTZjgZ6Fij6lpyg1UQhKJ1773t8fOZ+VDA=; b=bY5Mfnl28dGVvXZNr8kKAjgrrErejNe+BHkNTHets1ITlOy7XcuiWKUZzMgaNzRu7ICpPh qh60vspnyEW58IriZbGFvPZaz+XgOSR0Pj/HywVF5wYV5Jwy0ExD+CIxcPDPbOqtOAKd4I CJQrDZOogG38be0V0Q9WWlYZTvS3x0Y= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-273-M8aklUbUOGa4y7s4gBPtKA-1; Mon, 21 Jun 2021 01:35:59 -0400 X-MC-Unique: M8aklUbUOGa4y7s4gBPtKA-1 Received: by mail-wm1-f72.google.com with SMTP id k16-20020a7bc3100000b02901d849b41038so3024809wmj.7 for ; Sun, 20 Jun 2021 22:35:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=RY9DMg40/fTZjgZ6Fij6lpyg1UQhKJ1773t8fOZ+VDA=; b=SwJ26DHwq37zdgpEXovc1fhoKgmcJBZuJsO0eGws4aARoFAStB2c7jdB+AvITRCVgP 96Aw9fkB2jV+UivF6IYVfEgv6LlPg/i6wuROWMJKBipwSA3LG4gBPAWnR24VH67/ekc1 +EEZvzByJXMgjrg4bGD4fGK1vz/gDRFQ2tFk3qk9p5ESE4SCTAPXNH8jK711SNXYl6Y4 hRJ5P8PhYhebVjlytDe4/ngUhtJtJ4WHg8DIDxgGOOJ/StEMqImt63I/ny5hYunZQJn5 G3rbvwPcQjODJrgIV/o+Ae7Py0K362yZuYS8QjzSjJB90N1fLfT5wc7Q3ChXCPGt6tql 2i3g== X-Gm-Message-State: AOAM531WTJutY1+AMDN8jz9RgCRIJ92Uvc59rZa4IZ0oijf8/AX4ZkKS MkHJe1Ne+ublURwPZPp+/LSAw4C0NGcuHM7Cn+voeiIAgyngXevLQ5wRA8aLXBmka3DwdjJ/2r/ oRx7MgQe/MMT38GURATHV4cicIUY= X-Received: by 2002:a5d:6583:: with SMTP id q3mr11825343wru.360.1624253758476; Sun, 20 Jun 2021 22:35:58 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzNVzD02BSHJ5YfAF1/SPXAwkkudd9JO9SOY1nKn8HyLYLX4v9IpbakIlVA1prWMh7+0Pf55Q== X-Received: by 2002:a5d:6583:: with SMTP id q3mr11825334wru.360.1624253758292; Sun, 20 Jun 2021 22:35:58 -0700 (PDT) Received: from localhost.localdomain ([151.29.58.33]) by smtp.gmail.com with ESMTPSA id f19sm16229383wre.48.2021.06.20.22.35.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Jun 2021 22:35:57 -0700 (PDT) Date: Mon, 21 Jun 2021 07:35:55 +0200 From: Juri Lelli To: Thomas Gleixner Cc: bigeasy@linutronix.de, linux-rt-users@vger.kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, bristot@redhat.com, Anna-Maria Behnsen Subject: Re: [RFC PATCH RT v2 1/2] time/hrtimer: Add PINNED_HARD mode for realtime hrtimers Message-ID: References: <20210616071705.166658-1-juri.lelli@redhat.com> <20210616071705.166658-2-juri.lelli@redhat.com> <87k0mqeofg.ffs@nanos.tec.linutronix.de> <87bl82e19d.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87bl82e19d.ffs@nanos.tec.linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org Hi, On 19/06/21 09:56, Thomas Gleixner wrote: > On Sat, Jun 19 2021 at 01:35, Thomas Gleixner wrote: > > The wild west of anything which scratches 'my itch' based on 'my use > > case numbers' in Linux ended many years ago and while RT was always a > > valuable playground for unthinkable ideas we definitely tried hard not > > to accept use case specific hacks wihtout a proper justification that it > > makes sense in general. > > > > So why are you even trying to sell this to me? > > I wouldn't have been that grumpy if you'd at least checked whether the > task is pinned. Still I would have told you that you "fix" it at the > wrong place. Ah, indeed. Pulled the trigger too early it seems. I'll ponder more. > Why on earth is that nohz heuristic trainwreck not even checking that? > It's not a RT problem and it's not a problem restricted to RT tasks > either. If a task is pinned then arming the timer on a random other CPU > is blatant nonsense independent of the scheduling class. Agree. Lemme look more into it. Thanks for the comments! Best, Juri