Re: 2.6.25-rc5-git6: Reported regressions from 2.6.24

[Gabriel C <crazy@frugalware.org>]

Thomas Gleixner wrote:
> On Sat, 22 Mar 2008, Gabriel C wrote:
>  > Now some time later CPU1 gets woken by an interrupt/IPI and runs the
>>> timer wheel. At this point the pm_timer which is the reference clock
>>> has already wrapped around, so the watchdog thinks that there is a
>>> huge time difference and marks the TSC unstable.
>>>
>>> Aside of that watchdog issue this also affects the other users of
>>> add_timer_on(): e.g. queue_delayed_work_on().
>>>
>>> Can you please apply the patch below and verify it with Andi's
>>> watchdog patch applied ? 
>>
>> Did that , git head , Andi's + your patch but TSC is still marked unstable.
> 
> Doh, stupid me. We do not reevaluate the timer wheel, when we just
> wake up via the smp_reschedule IPI when the resched flag on the other
> CPU is not set. That's a separate vector which is not going through
> irq_enter() / irq_exit(). 
> 
> Does the patch below solve the problem ?

With this one TSC is fine but now I get a warning on boot :

..

[    0.041037] ------------[ cut here ]------------
[    0.041052] WARNING: at arch/x86/kernel/smp_32.c:562 native_smp_call_function_mask+0x23/0x11e()
[    0.041074] Modules linked in:
[    0.041087] Pid: 1, comm: swapper Not tainted 2.6.25-rc6-00243-g028011e-dirty #12
[    0.041107]  [<c011b51c>] warn_on_slowpath+0x40/0x65
[    0.041128]  [<c012b543>] autoremove_wake_function+0xd/0x2d
[    0.041148]  [<c033f28b>] schedule_timeout+0x13/0x99
[    0.041167]  [<c011690d>] __wake_up+0x29/0x39
[    0.041182]  [<c011690d>] __wake_up+0x29/0x39
[    0.041197]  [<c0128769>] call_usermodehelper_exec+0x97/0xa2
[    0.041214]  [<c010dff4>] native_smp_call_function_mask+0x23/0x11e
[    0.041233]  [<c01d4a66>] kobject_uevent_env+0x346/0x368
[    0.041251]  [<c010e46d>] smp_call_function_single+0x50/0x6f
[    0.041268]  [<c01336d2>] tick_nohz_rescan_timers_on+0x27/0x2b
[    0.041287]  [<c013109f>] clocksource_register+0x162/0x174
[    0.041306]  [<c0436203>] kernel_init+0x126/0x25e
[    0.041322]  [<c011943d>] schedule_tail+0x17/0x44
[    0.041337]  [<c0103c7a>] ret_from_fork+0x6/0x1c
[    0.041353]  [<c04360dd>] kernel_init+0x0/0x25e
[    0.041367]  [<c04360dd>] kernel_init+0x0/0x25e
[    0.041381]  [<c01049ab>] kernel_thread_helper+0x7/0x10
[    0.041397]  =======================
[    0.041417] ---[ end trace ca143223eefdc828 ]---     

..

Full dmesg there ->    http://frugalware.org/~crazy/dmesg/dmesg_tsc  

                                                                                                
>
> Thanks,
> 
> 	tglx
> 

Gabriel