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Date: Mon, 22 Dec 2008 22:35:16 +0100
From: "Fabio Comolli" <fabio.comolli@...il.com>
To: "Thomas Gleixner" <tglx@...utronix.de>
Cc: "Ingo Molnar" <mingo@...e.hu>, "Rafael J. Wysocki" <rjw@...k.pl>,
"Peter Zijlstra" <peterz@...radead.org>,
"Steven Rostedt" <srostedt@...hat.com>, dsaxena@...xity.net,
LKML <linux-kernel@...r.kernel.org>,
"Dave Kleikamp" <shaggy@...ux.vnet.ibm.com>, toralf.foerster@....de
Subject: Re: TSC not updating after resume: Bug or Feature?
Hi Thomas.
On Mon, Dec 22, 2008 at 10:13 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
> Fabio,
>
> On Mon, 22 Dec 2008, Fabio Comolli wrote:
>> Hi Thomas.
>>
>> On Mon, Dec 22, 2008 at 9:36 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
>> > On Mon, 22 Dec 2008, Thomas Gleixner wrote:
>> >> On Mon, 22 Dec 2008, Ingo Molnar wrote:
>> >> > * Thomas Gleixner <tglx@...utronix.de> wrote:
>> >> >
>> >> > > > By the way, I don't know if it matters but the problema happened with
>> >> > > > in-kernel hibernation and also in out-of-tree TuxOnIce hibernation.
>> >> > > > Maybe this can help debugging the issue, I don't know.
>> >> > >
>> >> > > Hmm, does not ring a bell here. Can you please apply the patch below to
>> >> > > mainline and retest ?
>> >> >
>> >> > ... and he should send a dmesg after a suspend cycle, right?
>> >>
>> >> Yes :)
>> >>
>> >> I digged more in the bugzillas. Toralf added some debug to
>> >> __update_sched_clock():
>> >>
>> >> - max_clock = wrap_max(scd->clock, scd->tick_gtod + TICK_NSEC);
>> >> + max_clock = scd->tick_gtod + TICK_NSEC;
>> >> + if (scd->clock > max_clock)
>> >> + printk(KERN_INFO "%d %d\n", scd->clock, max_clock);
>> >>
>> >> The interesting output is:
>> >>
>> >> Dec 14 21:55:55 n22 Back to C!
>> >> Dec 14 21:55:55 n22 Extended CMOS year: 2000
>> >> Dec 14 21:55:55 n22 Force enabled HPET at resume
>> >> Dec 14 21:55:55 n22 212611283 77
>> >>
>> >> The 77 is totaly bogus and it's likely not just a truncation of the
>> >> 64bit value because (scd->clock > max_clock) evaluates to true. This
>> >> output is _AFTER_ timekeeping resume because the HPET force enable
>> >> message comes from timekeeping resume.
>> >
>> > Seems I'm talking to myself, but I think I finally decoded the
>> > mystery:
>> >
>> > resume()
>> > cpufreq_resume()
>> > tsc:time_cpufreq_notifier()
>> > set_cyc2ns_scale()
>> > sched_clock_idle_sleep_event()
>> > sched_clock_tick()
>> > ktime_get()
>> > hpet_read()
>> >
>> > This happens _BEFORE_ timekeeping has resumed, so hpet_read() returns
>> > nonsense and the timekeeping code uses the stale pre suspend
>> > xtime/clocksource reference values to calculate the time. So the gtod
>> > reference in sched_clock can result in total crap depending on the
>> > time when the suspend happened.
>> >
>> > Shaggys patch clamps sched_clock to the stale scd->clock value which
>> > might explain the further wreckage.
>> >
>> > The above sequence happens only for CPUs with a CPU frequency coupled
>> > TSC, so on newer machines with CPU frequency invariant TSC this does
>> > not happen.
>> >
>> > /me stomps off to find a box to confirm that.
>> >
>>
>> Ok, just for reference here is my
>>
>> fcomolli@...king:~> cat /proc/cpuinfo
>> processor : 0
>> vendor_id : GenuineIntel
>> cpu family : 6
>> model : 13
>> model name : Intel(R) Pentium(R) M processor 1.73GHz
>> stepping : 8
>> cpu MHz : 800.000
>> cache size : 2048 KB
>> fdiv_bug : no
>> hlt_bug : no
>> f00f_bug : no
>> coma_bug : no
>> fpu : yes
>> fpu_exception : yes
>> cpuid level : 2
>> wp : yes
>> flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
>> pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx up bts est tm2
>> bogomips : 1596.95
>> clflush size : 64
>> power management:
>
> Can please you revert the last patch and apply the following ? Does
> the WARN_ON trigger ?
>
> Thanks,
>
> tglx
> ---
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index fa05e88..0d1526d 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -46,6 +46,9 @@ struct timespec xtime __attribute__ ((aligned (16)));
> struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
> static unsigned long total_sleep_time; /* seconds */
>
> +/* flag for if timekeeping is suspended */
> +static int timekeeping_suspended;
> +
> static struct timespec xtime_cache __attribute__ ((aligned (16)));
> void update_xtime_cache(u64 nsec)
> {
> @@ -92,6 +95,8 @@ void getnstimeofday(struct timespec *ts)
> unsigned long seq;
> s64 nsecs;
>
> + WARN_ON(timekeeping_suspended);
> +
> do {
> seq = read_seqbegin(&xtime_lock);
>
> @@ -299,8 +304,6 @@ void __init timekeeping_init(void)
> write_sequnlock_irqrestore(&xtime_lock, flags);
> }
>
> -/* flag for if timekeeping is suspended */
> -static int timekeeping_suspended;
> /* time in seconds when suspend began */
> static unsigned long timekeeping_suspend_time;
>
>
Yes, it does:
[ 159.487588] Syncing filesystems ... done.
[ 159.488523] Freezing user space processes ... (elapsed 0.00 seconds) done.
[ 159.489763] Freezing remaining freezable tasks ... (elapsed 0.00
seconds) done.
[ 159.491144] PM: Shrinking memory... done (0 pages freed)
[ 159.556730] PM: Freed 0 kbytes in 0.06 seconds (0.00 MB/s)
[ 159.556752] Suspending console(s) (use no_console_suspend to debug)
[ 159.557328] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 159.621764] pciehp 0000:00:1c.0:pcie02: pciehp_suspend ENTRY
[ 159.621989] ACPI handle has no context!
[ 159.621999] tifm_7xx1 0000:06:06.3: PCI INT A disabled
[ 159.622008] ACPI handle has no context!
[ 159.636240] ACPI handle has no context!
[ 159.652272] eth1: Going into suspend...
[ 159.655644] ipw2200 0000:06:05.0: PCI INT A disabled
[ 159.655652] ACPI handle has no context!
[ 159.668043] [fglrx] Power down the ASIC .
[ 159.764052] fglrx_pci 0000:01:00.0: PCI INT A disabled
[ 159.764175] ata2: port disabled. ignoring.
[ 159.764232] ata_piix 0000:00:1f.1: PCI INT A disabled
[ 159.764507] Intel ICH 0000:00:1e.2: PCI INT A disabled
[ 159.764646] ehci_hcd 0000:00:1d.7: PCI INT A disabled
[ 159.764686] uhci_hcd 0000:00:1d.3: PCI INT D disabled
[ 159.764725] uhci_hcd 0000:00:1d.2: PCI INT C disabled
[ 159.764764] uhci_hcd 0000:00:1d.1: PCI INT B disabled
[ 159.764803] uhci_hcd 0000:00:1d.0: PCI INT A disabled
[ 159.764808] pciehp 0000:00:1c.0:pcie02: pciehp_suspend ENTRY
[ 159.765572] ACPI: Preparing to enter system sleep state S4
[ 159.766924] Disabling non-boot CPUs ...
[ 159.767100] PM: Creating hibernation image:
[ 159.768005] PM: Need to copy 178481 pages
[ 159.768005] Intel machine check architecture supported.
[ 159.768005] Intel machine check reporting enabled on CPU#0.
[ 159.768005] ------------[ cut here ]------------
[ 159.768005] WARNING: at kernel/time/timekeeping.c:98
getnstimeofday+0x21/0xcd()
[ 159.768005] Modules linked in: cisco_ipsec(P) fglrx(P)
[ 159.768005] Pid: 5883, comm: s2disk Tainted: P
2.6.28-rc9-00050-gf8fd8a7 #9
[ 159.768005] Call Trace:
[ 159.768005] [<c0122ef8>] warn_on_slowpath+0x40/0x61
[ 159.768005] [<c024ddec>] acpi_ex_insert_into_field+0x2cf/0x2ef
[ 159.768005] [<c0154c53>] __rmqueue_smallest+0xbe/0x133
[ 159.768005] [<c01389a2>] getnstimeofday+0x21/0xcd
[ 159.768005] [<c0135e26>] ktime_get_ts+0x1d/0x3f
[ 159.768005] [<c0135e57>] ktime_get+0xf/0x2b
[ 159.768005] [<c013736b>] sched_clock_tick+0x46/0x83
[ 159.768005] [<c01373ad>] sched_clock_idle_wakeup_event+0x5/0xa
[ 159.768005] [<c0108670>] set_cyc2ns_scale+0x3f/0x5e
[ 159.768005] [<c01088af>] time_cpufreq_notifier+0xf9/0x103
[ 159.768005] [<c0136782>] notifier_call_chain+0x2a/0x52
[ 159.768005] [<c0136866>] __srcu_notifier_call_chain+0x35/0x4a
[ 159.768005] [<c0136884>] srcu_notifier_call_chain+0x9/0xc
[ 159.768005] [<c031cbca>] cpufreq_resume+0xf3/0x112
[ 159.768005] [<c028c3f3>] __sysdev_resume+0x24/0x34
[ 159.768005] [<c028c421>] sysdev_resume+0x1e/0x50
[ 159.768005] [<c0290637>] device_power_up+0x8/0x10
[ 159.768005] [<c0149478>] create_image+0x8f/0x9f
[ 159.768005] [<c01494ed>] hibernation_snapshot+0x65/0xce
[ 159.768005] [<c014bddc>] snapshot_ioctl+0x208/0x47d
[ 159.768005] [<c014bbd4>] snapshot_ioctl+0x0/0x47d
[ 159.768005] [<c017a279>] vfs_ioctl+0x1c/0x5f
[ 159.768005] [<c017a785>] do_vfs_ioctl+0x167/0x172
[ 159.768005] [<c017a7bc>] sys_ioctl+0x2c/0x42
[ 159.768005] [<c01038cd>] sysenter_do_call+0x12/0x35
[ 159.768005] ---[ end trace 828aa214905e8df0 ]---
[ 313.187879] Force enabled HPET at resume
[ 159.771124] ACPI: Waking up from system sleep state S4
[ 159.792183] ACPI: EC: non-query interrupt received, switching to
interrupt mode
[ 159.855414] pcieport-driver 0000:00:01.0: setting latency timer to 64
[ 159.855497] pcieport-driver 0000:00:1c.0: setting latency timer to 64
[ 159.855502] pciehp 0000:00:1c.0:pcie02: pciehp_resume ENTRY
[ 160.856182] uhci_hcd 0000:00:1d.0: PCI INT A -> GSI 23 (level, low) -> IRQ 23
[ 160.856190] uhci_hcd 0000:00:1d.0: setting latency timer to 64
[ 160.856237] uhci_hcd 0000:00:1d.1: PCI INT B -> GSI 19 (level, low) -> IRQ 19
[ 160.856244] uhci_hcd 0000:00:1d.1: setting latency timer to 64
[ 160.856291] uhci_hcd 0000:00:1d.2: PCI INT C -> GSI 18 (level, low) -> IRQ 18
[ 160.856297] uhci_hcd 0000:00:1d.2: setting latency timer to 64
[ 160.856343] uhci_hcd 0000:00:1d.3: PCI INT D -> GSI 16 (level, low) -> IRQ 16
[ 160.856350] uhci_hcd 0000:00:1d.3: setting latency timer to 64
[ 160.856396] ehci_hcd 0000:00:1d.7: PCI INT A -> GSI 23 (level, low) -> IRQ 23
[ 160.856404] ehci_hcd 0000:00:1d.7: setting latency timer to 64
[ 160.856521] pci 0000:00:1e.0: setting latency timer to 64
[ 160.856569] Intel ICH 0000:00:1e.2: PCI INT A -> GSI 17 (level,
low) -> IRQ 17
[ 160.856576] Intel ICH 0000:00:1e.2: setting latency timer to 64
[ 161.870198] ata_piix 0000:00:1f.1: restoring config space at offset
0x1 (was 0x2880001, writing 0x2880005)
[ 161.870211] ata_piix 0000:00:1f.1: PCI INT A -> GSI 18 (level, low) -> IRQ 18
[ 161.870216] ata_piix 0000:00:1f.1: setting latency timer to 64
[ 161.870669] fglrx_pci 0000:01:00.0: power state changed by ACPI to D0
[ 161.870679] fglrx_pci 0000:01:00.0: PCI INT A -> GSI 16 (level,
low) -> IRQ 16
[ 161.870684] fglrx_pci 0000:01:00.0: setting latency timer to 64
[ 161.883293] ata2: port disabled. ignoring.
[ 161.884515] [fglrx] Power up the ASIC
[ 161.884554] eth1: Coming out of suspend...
[ 161.900173] ipw2200 0000:06:05.0: enabling device (0000 -> 0002)
[ 161.900181] ipw2200 0000:06:05.0: PCI INT A -> GSI 20 (level, low) -> IRQ 20
[ 161.900196] ipw2200 0000:06:05.0: restoring config space at offset
0xf (was 0x18030100, writing 0x1803010b)
[ 161.900226] ipw2200 0000:06:05.0: restoring config space at offset
0x4 (was 0x0, writing 0xc8206000)
[ 161.900234] ipw2200 0000:06:05.0: restoring config space at offset
0x3 (was 0x0, writing 0x8008)
[ 161.900243] ipw2200 0000:06:05.0: restoring config space at offset
0x1 (was 0x2900002, writing 0x2900116)
[ 162.072723] ata1.01: ACPI cmd ef/03:0c:00:00:00:b0 filtered out
[ 162.072726] ata1.01: ACPI cmd ef/03:22:00:00:00:b0 filtered out
[ 162.080461] ata1.00: ACPI cmd ef/03:0c:00:00:00:a0 filtered out
[ 162.080463] ata1.00: ACPI cmd ef/03:45:00:00:00:a0 filtered out
[ 162.096951] ata1.00: configured for UDMA/100
[ 162.128666] ata1.01: configured for MWDMA2
[ 162.129488] sd 0:0:0:0: [sda] 156301488 512-byte hardware sectors:
(80.0 GB/74.5 GiB)
[ 162.129519] sd 0:0:0:0: [sda] Write Protect is off
[ 162.129521] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 162.129569] sd 0:0:0:0: [sda] Write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[ 162.129621] sd 0:0:0:0: [sda] 156301488 512-byte hardware sectors:
(80.0 GB/74.5 GiB)
[ 162.129648] sd 0:0:0:0: [sda] Write Protect is off
[ 162.129650] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 162.129696] sd 0:0:0:0: [sda] Write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[ 162.168175] firewire_ohci 0000:06:06.2: restoring config space at
offset 0xf (was 0x4020300, writing 0x402030b)
[ 162.168203] firewire_ohci 0000:06:06.2: restoring config space at
offset 0x5 (was 0x0, writing 0xc8200000)
[ 162.168211] firewire_ohci 0000:06:06.2: restoring config space at
offset 0x4 (was 0x0, writing 0xc8208000)
[ 162.168218] firewire_ohci 0000:06:06.2: restoring config space at
offset 0x3 (was 0x800000, writing 0x808008)
[ 162.168228] firewire_ohci 0000:06:06.2: restoring config space at
offset 0x1 (was 0x2100000, writing 0x2100116)
[ 162.256038] tifm_7xx1 0000:06:06.3: restoring config space at
offset 0xf (was 0x40701ff, writing 0x407010a)
[ 162.256067] tifm_7xx1 0000:06:06.3: restoring config space at
offset 0x4 (was 0x0, writing 0xc8204000)
[ 162.256075] tifm_7xx1 0000:06:06.3: restoring config space at
offset 0x3 (was 0x800000, writing 0x808008)
[ 162.256085] tifm_7xx1 0000:06:06.3: restoring config space at
offset 0x1 (was 0x2100000, writing 0x2100106)
[ 162.256107] tifm_7xx1 0000:06:06.3: PCI INT A -> GSI 22 (level,
low) -> IRQ 22
[ 162.256283] pciehp 0000:00:1c.0:pcie02: pciehp_resume ENTRY
[ 163.260341] sd 0:0:0:0: [sda] Starting disk
[ 163.800031] usb 3-1: reset full speed USB device using uhci_hcd and address 2
[ 164.014985] Restarting tasks ... done.
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