Message-ID: <473C825E.3030307@rtr.ca>
Date: Thu, 15 Nov 2007 12:31:10 -0500
From: Mark Lord <lkml@rtr.ca>
User-Agent: Thunderbird 2.0.0.6 (X11/20070728)
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To: Pavel Machek <pavel@ucw.cz>
Cc: Mark Lord <liml@rtr.ca>, Thomas Gleixner <tglx@linutronix.de>,
       len.brown@intel.com, Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org,
       rjw@sisk.pl, Ingo Molnar <mingo@elte.hu>
Subject: Re: [BUG] Strange 1-second pauses during Resume-from-RAM
References: <32209efe0711122242m3a5f081asf1c11a38b24db10c@mail.gmail.com> <20071113031553.3c7b5c16.akpm@linux-foundation.org> <4739ADA2.4060604@rtr.ca> <alpine.LFD.0.9999.0711131521590.3265@localhost.localdomain> <4739E347.30406@rtr.ca> <473C7495.40805@rtr.ca> <20071115181418.GA6603@ucw.cz>
In-Reply-To: <20071115181418.GA6603@ucw.cz>
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> Hi!
> 
>> > I have been reporting this off and on since 2.6.23 was released.
>> > This problem was not apparent up to perhaps 2.6.23-rc8,
>> > but definitely became common in 2.6.23 and 2.6.23.1.
>> > 
>> > Most of the time, a resume-from-RAM on my notebook takes about 2.1 seconds
>> > of kernel time to complete.
>> > 
>> > Once in a while, it takes *much* longer, in the 14-20 second range.
>> > These long events *seem* to be mostly after the notebook has been
>> > in suspend for a longish time, but there's really nothing consistent here.
>> > 
>> > So git-bisect isn't going to work for this one.   I recently rebuilt the 
>> > kernel
>> > to include printk timestamps, and then it went 2 days without the issue 
>> > happening,
>> > until this morning (after an overnight suspend) finally.
>> > 
>> > The machine is a Dell Inspiron 9400, Intel chipset + Core2Duo 2.1GHZ w/3GB 
>> > DDR2.
>> > PCIe express chipset, ATI graphics, SATA hard drive.
>> > 
>> > 00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT 
>> > Express Memory Controller Hub (rev 03)
>> > 00:01.0 PCI bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT 
>> > Express PCI Express Root Port (rev 03)
>> > 00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High 
>> > Definition Audio Controller (rev 01)
>> > 00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 
>> > 1 (rev 01)
>> > 00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 
>> > 2 (rev 01)
>> > 00:1c.3 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 
>> > 4 (rev 01)
>> > 00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #1 
>> > (rev 01)
>> > 00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #2 
>> > (rev 01)
>> > 00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #3 
>> > (rev 01)
>> > 00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #4 
>> > (rev 01)
>> > 00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI 
>> > Controller (rev 01)
>> > 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1)
>> > 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface 
>> > Bridge (rev 01)
>> > 00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) Serial 
>> > ATA Storage Controller IDE (rev 01)
>> > 00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 
>> > 01)
>> > 01:00.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility 
>> > X1400
>> > 03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX 
>> > (rev 02)
>> > 03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd Unknown device 0832
>> > 03:01.1 Generic system peripheral [0805]: Ricoh Co Ltd R5C822 
>> > SD/SDIO/MMC/MS/MSPro Host Adapter (rev 19)
>> > 03:01.2 System peripheral: Ricoh Co Ltd Unknown device 0843 (rev 01)
>> > 03:01.3 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host 
>> > Adapter (rev 0a)
>> > 03:01.4 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 05)
>> > 0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network 
>> > Connection (rev 02)
>> > 
>> > There's also a USB2 hub connected, with the Logitech mouse being the
>> > only thing plugged into it at present.
>> > 
>> > The best clue I have of what is happening, other than that it was first
>> > seen during the late 2.6.23-rc* series, are the following two sets of
>> > kernel logs.  The first set is from a "normal" fast wake-up,
>> > and the second set is from the "slow" wake-up seen this morning.
>> > 
>> > Both logs show the same information, in pretty much the same order.
>> > The BIG difference is a bunch of unexplained pauses of exactly 1-second
>> > each that occur during the slow wakeup.
>> > 
>> > The only other difference is that the SATA disk messages are placed
>> > differently within the two logs.  I'm thinking on that one but it
>> > doesn't look significant to me.
>> > 
>> > The real question is, why the 1-sec pauses?
> 
> Can you try nohz=off highres=off? Strange stuff is happening with
> nohz.
..

(added Ingo to CC: list:  maybe this is some weird interaction with CFS
and jiffies being reset to 0 on resume ??)

I can try it, but it won't help debug the problem much.
Remember, this happens very inconsistently, maybe 3-4 times a day,
or not at all for 3-4 days.

But if somebody has a specific bug-fix patch that could explain this,
then I'll happily apply it here.

Cheers
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