2.6.25.2 - Jiffies/Time jumping back and forth (Regereesion from 2.6.24)
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From: Martin Knoblauch on 7 May 2008 08:50 Hi, 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 Cheers Martin ------------------------------------------------------ Martin Knoblauch email: k n o b i AT knobisoft DOT de www: http://www.knobisoft.de -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Bart Van Assche on 7 May 2008 09:10 On Wed, May 7, 2008 at 2:42 PM, Martin Knoblauch <spamtrap(a)knobisoft.de> 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, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Martin Knoblauch on 7 May 2008 11:10 ----- Original Message ---- > From: Bart Van Assche <bart.vanassche(a)gmail.com> > To: Martin Knoblauch <spamtrap(a)knobisoft.de> > Cc: linux-kernel(a)vger.kernel.org; hmh(a)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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Martin Knoblauch on 7 May 2008 12:00 ----- Original Message ---- > From: Martin Knoblauch <spamtrap(a)knobisoft.de> > To: Bart Van Assche <bart.vanassche(a)gmail.com> > Cc: linux-kernel(a)vger.kernel.org; hmh(a)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(a)vger.kernel.org; hmh(a)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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: john stultz on 7 May 2008 13:10
On Wed, May 7, 2008 at 5:42 AM, Martin Knoblauch <spamtrap(a)knobisoft.de> wrote: > Hi, > > 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 With this issue you're seeing is only the printk timestamps jumping back, correct? For example, you're not seeing the output from gettimeofday() or the actual jiffies value (as seen from maybe a driver) jump backward? Is that right? The printk timestamps may jump around a bit at bootup, especially if you have unsynced TSCs, so that is a known issue. However its not known to have any actual negative effect other then maybe causing the dmesg log to be a bit confusing. thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |