From owner-freebsd-current Sat Feb 16 16:28:29 2002 Delivered-To: freebsd-current@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id 0AA1137B402 for ; Sat, 16 Feb 2002 16:28:27 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id g1H0SQZ41827; Sat, 16 Feb 2002 16:28:26 -0800 (PST) (envelope-from dillon) Date: Sat, 16 Feb 2002 16:28:26 -0800 (PST) From: Matthew Dillon Message-Id: <200202170028.g1H0SQZ41827@apollo.backplane.com> To: freebsd-current@freebsd.org Subject: 'microuptime() went backwards ...' using ACPI timer. Shouldn't that be impossible? Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Testing with a 'make -j 10 buildworld' on a -current box I am getting regular: microuptime() went backwards (146.826785 -> 146.156715) microuptime() went backwards (146.826782 -> 146.228636) ... microuptime() went backwards (8945.938288 -> 8945.251603) microuptime() went backwards (8945.938306 -> 8945.347173) microuptime() went backwards (9142.847550 -> 9142.847546) This occurs both with and without the gettimeofday Giant-removal patch, so I am fairly sure it has nothing to do with any of my current work. This is running -current on a DELL2550 (2xCPUs), compiled with the SMP option. Timecounter "i8254" frequency 1193182 Hz ... Timecounter "ACPI" frequency 3579545 Hz acpi_timer0: <32-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0 acpi_cpu0: on acpi0 acpi_cpu1: on acpi0 acpi_pcib0: on acpi0 ... Question: How can this be occuring at all? Isn't the ACPI counter a 32 bit counter that does not have the rollover problems that the 8254 timer has? -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message