On Dec 8, 2007 6:12 PM, Parag Warudkar <parag.warudkar@gmail.com> wrote:
quoted text
> No problems after disabling CONFIG_HIGHRES_TIMERS , CONFIG_CPU_IDLE
> and CONFIG_NO_HZ.
>
> I will try enabling them one by one - HRT, NOHZ and CPU_IDLE last -
> that way we can at least tell what is required to be hit with this
> problem.

Looks like CPU_IDLE=y is necessary for the problem to show up.
With CPU_IDLE=n HRT+NO_HZ+TICK_ONESHOT does not give soft lockup problems.
(Actually with HIGH_RES_TIMERS=NO_HZ=TICK_ONESHOT=y  I do see short
freezes on ssh - when I cannot type anything for may be a second even
under 100% idle. But Soft Lock up doesnt show up in dmesg with this
configuration.)

No Soft Lockup - CPU_IDLE=n 5+ Hours uptime
---------------------------------------------------------------------------
HIGH_RES_TIMERS=NO_HZ=TICK_ONESHOT=n
HIGH_RES_TIMERS=y NO_HZ=TICK_ONESHOT=n
HIGH_RES_TIMERS=NO_HZ=y TICK_ONESHOT=n
HIGH_RES_TIMERS=NO_HZ=TICK_ONESHOT=y - short freezes.


Soft Lockup - CPU_IDLE=y 2 hours uptime
--------------------------------------------------------------------------
HIGH_RES_TIMERS=NO_HZ=TICK_ONESHOT=y

dmesg -

BUG: soft lockup - CPU#1 stuck for 11s! [swapper:0]

Pid: 0, comm: swapper Not tainted (2.6.24-rc4 #13)
EIP: 0060:[<c0603eaa>] EFLAGS: 00000202 CPU: 1
EIP is at _spin_lock_irqsave+0x16/0x27
EAX: c06b4110 EBX: 00000001 ECX: f7873808 EDX: 00000293
ESI: 00000005 EDI: f7873808 EBP: 00000000 ESP: f7829f10
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: 800f5958 CR3: 37284000 CR4: 000006d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
 [<c0438293>] tick_broadcast_oneshot_control+0x10/0xda
 [<c0437ce2>] tick_notify+0x1d4/0x2eb
 [<c04281bc>] get_next_timer_interrupt+0x143/0x1b4
 [<c06058a1>] notifier_call_chain+0x2a/0x47
 [<c04345c0>] raw_notifier_call_chain+0x17/0x1a
 [<c043781e>] clockevents_notify+0x19/0x4f
 [<c0533d23>] acpi_idle_enter_simple+0x183/0x1d0
 [<c058cf03>] cpuidle_idle_call+0x53/0x78
 [<c058ceb0>] cpuidle_idle_call+0x0/0x78
 [<c0402575>] cpu_idle+0x97/0xb8
 =======================

Parag
--
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/