From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 022A21E492 for ; Mon, 31 Mar 2025 07:54:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743407649; cv=none; b=fQ/GLjiuTPjBWsWtZuGfnhp0SCTiTs3vQe3rlMVKjmiUi6jpOPljuYWSq9ANnjIp2JV7WasceXZ6H2TRjN1eDFQoNoo2xYrCJwN1utCJe3dJ87nyDkRmJOZTiUPqzRTiFesQtIhRe+hJnEien4wGCd6ig32GG3z2b101daSHP3c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743407649; c=relaxed/simple; bh=pSOWZdd/MbIKZjh443M8gHoV68P+KisZJPKaJJZIdxc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lRfp1QsIs3AavbvMrMv6pF3xoR6q/HfpGcxS1679usCyQHY7ZAxNOd2TVygwbcRgdq5wf7/Wa7YT+BvoBle40b6+A25TugzDdS6/QYVaZbWtfXfLXB4TqFDyziGI241DRGF48EOH9WIln931PoAZ6mm40vIJxOsShPz9T5/Ogak= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=J+oaACnb; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="J+oaACnb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1743407646; 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=snXUyEbtvmR9vqAWor24hXesFNJShZnkZEKY6CqFCEo=; b=J+oaACnbMc9A2lcB/TB79BfJyVpO4okJMUgq4IX0XgE7D6S+mDXzGK7B91SxmhX54N0fhU kUv7/1Kupt33WMGezN3XXs1GptZsLXnZj9wcWSFqTh6GMavjbY/+fbFoNefqzDfTFlQFl5 jJPFtDimWr6U0b+RdgcG8CqC5YfiXO4= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-563-efZpDS6VPUyk1jmXzLmYFA-1; Mon, 31 Mar 2025 03:54:01 -0400 X-MC-Unique: efZpDS6VPUyk1jmXzLmYFA-1 X-Mimecast-MFC-AGG-ID: efZpDS6VPUyk1jmXzLmYFA_1743407640 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9CA50180087D; Mon, 31 Mar 2025 07:53:59 +0000 (UTC) Received: from localhost (unknown [10.43.135.229]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A119C180094A; Mon, 31 Mar 2025 07:53:56 +0000 (UTC) Date: Mon, 31 Mar 2025 09:53:53 +0200 From: Miroslav Lichvar To: Thomas Gleixner Cc: John Stultz , LKML , Stephen Boyd , Anna-Maria Behnsen , Frederic Weisbecker , Shuah Khan , linux-kselftest@vger.kernel.org, kernel-team@android.com, Lei Chen Subject: Re: [PATCH v2 1/2] time/timekeeping: Fix possible inconsistencies in _COARSE clockids Message-ID: References: <20250320200306.1712599-1-jstultz@google.com> <874izezv3c.ffs@tglx> <87bjtmxtuc.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87bjtmxtuc.ffs@tglx> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On Thu, Mar 27, 2025 at 06:32:27PM +0100, Thomas Gleixner wrote: > On Thu, Mar 27 2025 at 16:42, Miroslav Lichvar wrote: > > On Thu, Mar 27, 2025 at 10:22:31AM +0100, Thomas Gleixner wrote: > > To clearly see the difference with the new code, I made an attempt > > to update the old linux-tktest simulation that was used back when the > > multiplier adjustment was reworked, but there are too many missing > > things now and I gave up. > > Can you point me to that code? It's this thing: https://github.com/mlichvar/linux-tktest > It would be probably useful to create a test mechanism which allows to > exercise all of this in a simulated way so we actually don't have to > wonder every time we change a bit what the consequences are. Yes, that would be very nice if we could run the timekeeping code in a deterministic simulated environment with a configurable clocksource, timing of kernel updates, timing and values of injected adjtimex() calls, etc. The question is how to isolate it. -- Miroslav Lichvar