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=-5.8 required=3.0 tests=BAYES_00,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 13939C433DB for ; Fri, 22 Jan 2021 12:32:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0D2821D7A for ; Fri, 22 Jan 2021 12:32:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727854AbhAVMbt (ORCPT ); Fri, 22 Jan 2021 07:31:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727162AbhAVMbl (ORCPT ); Fri, 22 Jan 2021 07:31:41 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7643EC06174A for ; Fri, 22 Jan 2021 04:31:01 -0800 (PST) Date: Fri, 22 Jan 2021 13:30:57 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1611318657; 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=rSi+Cl424xasLfdnola1Eti3Z3BzrrUt2w9Nrf2fd+0=; b=HYApeeGZpNV5CkoyOfsbLxz8O6UOs2R9iOD5R7WOBThzEoMAWh8LK0BVBESm2avPiUPP+c 5DPpeBne2DaBaoPTE6FbzGj15LRcBW9lqpJq8AvxMGYckT1eck3vWPjFDCSi/lzF75S+D3 +VLimsGc/aEzSq1uFtiauh6BdriqVZThJ83sFCMBj0ZbRXpIBEHMBSd8wBHX/1C6tusGkN F6G84fxfCGozNf1fsw8aJfiwvlUN0S75paIrgggjz7nieq6onBMFSDpQDKI4NuR9REpQdM L2ViqrDFuh1Zv3xuTM+2F3PWajfW2QGqXDlHQP+/SSKYDugE5AGdNYul2+h9hg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1611318657; 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=rSi+Cl424xasLfdnola1Eti3Z3BzrrUt2w9Nrf2fd+0=; b=9Hzd5TrCMDiXR3EBUUL618h9CUnLSD3WgrtcqVI36ryhQnj9gnhCFWScF0CEtiaiaTqDwG sdsB+m2Es+x5kYBQ== From: Sebastian Andrzej Siewior To: Sebastien Laveze Cc: linux-rt-users@vger.kernel.org Subject: Re: timerfd performances Message-ID: <20210122123057.72aeag672rh3omcw@linutronix.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 2021-01-18 17:10:15 [+0100], Sebastien Laveze wrote: > Hi, Hi, > In the end, it seems my most viable option at the moment is to move to > clock_nanosleep() but it implies radical changes in my application > architecture as it's not as scalable and flexible as timerfd. > > Any hints on how to "secure" the wake-up latency of timer fds or what > is expected in future works would be greatly appreciated ! Splitting the timer-wakeups back into ktimersoftd would look like helping. But note that all timer wake ups would happen there - even the accumulated case where we have to wake 100 tasks at once. This would then probably ask for split on SCHED_OTHER vs RT tasks like it is done for clock_nanosleep(). > Thanks, > Seb Sebastian