From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 AF880145355 for ; Tue, 2 Sep 2025 10:52:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756810362; cv=none; b=KiNHlfBqrZnX9srGq8dGuVlxAJqCCYHf8yA8jzxtLv4I2ZvDx7utk+jKUsyXD4SyW8xFvME8TRFZEHbslPP59xFaYYYt3r2ASTvZGg7HIXRbfYktP8loEHWnYp5jeUIom3aOZ5L/AQK+QfL2dzTt/wOxgES7oopdg9eI6CIPsKA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756810362; c=relaxed/simple; bh=q1vBjZpuXBRx1O5MdCs7fZZzXldF+XnBB1LspypyKKI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=KMz7Uro/I2NJjOQcngBWL0JapcGUuyiqmUm9J0vo9e6EL3Q3IdVfCfSNEumSb1htYgNVAc6nLudExUEwC9z66MvoE6M1fnbcAsW6QQlX+CcMwMfbuBKgXyKE6IhTpBbpb8GJvGM9K91qQWGJaQ/uahjKWO2G8iAg8VNey9l8EdE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=0VnCVdC0; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=XIyDwmlW; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="0VnCVdC0"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="XIyDwmlW" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1756810359; 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=bMJmfqvFyy+iMjlsEXM1T/zdFCArF7GdodLlr0nVrKU=; b=0VnCVdC0JyOreFu3txAY0etBQuxWxqRKTml8V+HWZEfTivRGtfFAO8jyd2nk7S39L9FdTw eL7/H4lQ3qZ60YSatsK7ZDZuTo8aIdWlu0QD2M/acFEEj2mxc2I7yB0/lcHOKGQkvQW8tC jXvXWxSfE9sWzlbUxwpMdZ/4JOAbcqARmnBEFFRcSZsfISFlz0lVLbJBNhp8PUiClaLslb SM5DxiOUcKx5+eyAcMol5z1K9Y6x4sPfkDOtYZoxYGQUeyl7VGSj2TO9/mRkEkGEW3mU1l DmKISSVy04TQg1UMApxvGZH6EKU4K3bbQslG737hdkgkh6tlrVF0me982/g39Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1756810359; 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=bMJmfqvFyy+iMjlsEXM1T/zdFCArF7GdodLlr0nVrKU=; b=XIyDwmlWNe7CWetzkBNJuLOoe+yzWUJhvHWqY5hbemAT0PYJda/K2pkJDjL8GWh8CYVXgS hb0U7dSgaUriFgDQ== To: Kaiwan N Billimoria Cc: Llillian@star-ark.net, agordeev@linux.ibm.com, akpm@linux-foundation.org, alexander.shishkin@linux.intel.com, anna-maria@linutronix.de, bigeasy@linutronix.de, catalin.marinas@arm.com, chenhuacai@kernel.org, francesco@valla.it, frederic@kernel.org, guoweikang.kernel@gmail.com, jstultz@google.com, kpsingh@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, maz@kernel.org, mingo@kernel.org, pmladek@suse.com, rrangel@chromium.org, sboyd@kernel.org, urezki@gmail.com, v-singh1@ti.com, will@kernel.org, Kaiwan N Billimoria Subject: Re: [RFC PATCH] time: introduce BOOT_TIME_TRACKER and minimal boot timestamp In-Reply-To: <20250902070253.936687-1-kaiwan.billimoria@gmail.com> References: <871pp14pkr.ffs@tglx> <20250902070253.936687-1-kaiwan.billimoria@gmail.com> Date: Tue, 02 Sep 2025 12:52:37 +0200 Message-ID: <87a53d2kju.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, Sep 02 2025 at 12:32, Kaiwan N. Billimoria wrote: > So, just confirming: here 1409443611 divided by 200 MHz gives us 7.047218055s > since boot, and thus the actual timestamp here is that plus 0.000001s yes? > (Over 7s here? yes, it's just that I haven't yet setup U-Boot properly for uSD > card boot, thus am manually loading commands in U-Boot to boot up, that's all). Looks about right. > A question (perhaps very stupid): will the hwcnt - the output of the read() - > be guaranteed to be (close to) the number of increments since processor > power-up (or reset)? Meaning, it's simply a hardware feature and agnostic to > what code the core was executing (ROM/BL/kernel), yes? Under the assumption that nothing on the way resets the counter. Thanks tglx