From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760917AbYEGPuk (ORCPT ); Wed, 7 May 2008 11:50:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756533AbYEGPu2 (ORCPT ); Wed, 7 May 2008 11:50:28 -0400 Received: from web32608.mail.mud.yahoo.com ([68.142.207.235]:28251 "HELO web32608.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755988AbYEGPu0 (ORCPT ); Wed, 7 May 2008 11:50:26 -0400 X-YMail-OSG: tKtxZ.oVM1kYzYNImgSgU33RvI4Yl7Fc.5qh.JfzAUl37vS6tzdkfsTAvpNHLJPLb4oo4f0Rbv7dl1TImG7M25sv4RbqJLXA.jDkEUoZt_1prYyeMeeqf17yXarfSxhq.WxiEB3iRC0jkqQ- X-Mailer: YahooMailRC/975.23 YahooMailWebService/0.7.185 Date: Wed, 7 May 2008 08:50:25 -0700 (PDT) From: Martin Knoblauch Subject: Re: 2.6.25.2 - Jiffies/Time jumping back and forth (Regereesion from 2.6.24) To: Bart Van Assche Cc: linux-kernel@vger.kernel.org, hmh@hmh.eng.br MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <530038.77501.qm@web32608.mail.mud.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ---- > From: Martin Knoblauch > To: Bart Van Assche > Cc: linux-kernel@vger.kernel.org; hmh@hmh.eng.br > Sent: Wednesday, May 7, 2008 5:02:23 PM > Subject: Re: 2.6.25.2 - Jiffies/Time jumping back and forth (Regereesion from 2.6.24) > > ----- Original Message ---- > > > From: Bart Van Assche > > To: Martin Knoblauch > > Cc: linux-kernel@vger.kernel.org; hmh@hmh.eng.br > > Sent: Wednesday, May 7, 2008 3:06:02 PM > > Subject: Re: 2.6.25.2 - Jiffies/Time jumping back and forth (Regereesion from > 2.6.24) > > > > On Wed, May 7, 2008 at 2:42 PM, Martin Knoblauch wrote: > > > > > > any news on the one below? I upgraded to 2.6.25.2 and the problem still > > persists. Would adding a bugzilla actually help ? :-) > > > > > > http://www.ussg.iu.edu/hypermail/linux/kernel/0804.2/1144.html > > > > I noticed a similar issue on 2.6.22 and 2.6.24 kernels: with ACPI > > disabled Linux' clock jumps backward and forward early during boot. > > See also the kernel messages from the attachment in comment #13 of > > http://bugzilla.kernel.org/show_bug.cgi?id=9936. > > > > Bart, > > Hi Bart, > > no this looks different. As soon as the timesource is detected, I see non-zero > timestamps > in dmesg, but they look smaller and jump in both directions. And I have never > seen this before > 2.6.25. > > It actually might be a good idea to get the dmesg output from 2.6.24. > > Cheers > Martin interesting - maybe related to clocksources. The HPET seems to be detected later in 2.6.25: 2.6.24: [ 0.000000] Initializing CPU#0 [ 0.000000] PID hash table entries: 4096 (order: 12, 32768 bytes) -->[ 0.000000] hpet clockevent registered -->[ 0.000000] TSC calibrated against HPET [ 150.233392] time.c: Detected 2327.502 MHz processor. [ 150.235525] Console: colour VGA+ 80x25 [ 150.235532] console [tty0] enabled [ 150.235546] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 150.235548] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 150.235549] ... MAX_LOCK_DEPTH: 30 [ 150.235550] ... MAX_LOCKDEP_KEYS: 2048 [ 150.235551] ... CLASSHASH_SIZE: 1024 [ 150.235552] ... MAX_LOCKDEP_ENTRIES: 8192 [ 150.235553] ... MAX_LOCKDEP_CHAINS: 16384 [ 150.235554] ... CHAINHASH_SIZE: 8192 [ 150.235556] memory used by lock dependency info: 1712 kB [ 150.235557] per task-struct memory footprint: 2160 bytes [ 150.235559] Checking aperture... [ 150.235568] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) [ 150.267666] Placing software IO TLB between 0x123c000 - 0x523c000 [ 150.377395] Memory: 8086092k/9437184k available (2901k kernel code, 301896k reserved, 1534k data, 772k init) [ 150.454897] Calibrating delay using timer specific routine.. 4659.71 BogoMIPS (lpj=9319423) 2.6.25.2: [ 0.000000] Initializing CPU#0 [ 0.000000] PID hash table entries: 4096 (order: 12, 32768 bytes) -->[ 0.000000] TSC calibrated against PM_TIMER [ 0.000004] time.c: Detected 2327.497 MHz processor. [ 0.002079] Console: colour VGA+ 80x25 [ 0.002086] console [tty0] enabled [ 0.002107] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 0.002109] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 0.002110] ... MAX_LOCK_DEPTH: 48 [ 0.002111] ... MAX_LOCKDEP_KEYS: 2048 [ 0.002112] ... CLASSHASH_SIZE: 1024 [ 0.002114] ... MAX_LOCKDEP_ENTRIES: 8192 [ 0.002115] ... MAX_LOCKDEP_CHAINS: 16384 [ 0.002116] ... CHAINHASH_SIZE: 8192 [ 0.002117] memory used by lock dependency info: 1712 kB [ 0.002119] per task-struct memory footprint: 3456 bytes [ 0.002121] Checking aperture... [ 0.002130] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) [ 0.004000] Placing software IO TLB between 0x15093000 - 0x19093000 [ 0.004000] Memory: 8110236k/9437184k available (2950k kernel code, 277752k reserved, 1567k data, 800k init) [ 0.004000] CPA: page pool initialized 1 of 1 pages preallocated -->[ 0.004000] hpet clockevent registered [ 0.080008] Calibrating delay using timer specific routine.. 4660.31 BogoMIPS (lpj=9320632) Any ideas how to force hpet earlier? Specifying hpet=force and/or clocksource=hpet did not help. Cheers Martin