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Re: [Qemu-devel] guest: NO_HZ FULL will not work with unstable sched clo
From: |
Stefan Priebe |
Subject: |
Re: [Qemu-devel] guest: NO_HZ FULL will not work with unstable sched clock |
Date: |
Sun, 16 Aug 2015 00:20:12 +0200 |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 |
same with kvm clock:
[ 0.195073] Switched to clocksource kvm-clock
[ 0.195509] ------------[ cut here ]------------
[ 0.195509] WARNING: CPU: 1 PID: 1 at kernel/time/tick-sched.c:192
can_stop_full_tick+0x1c1/0x200()
[ 0.195515] NO_HZ FULL will not work with unstable sched clock
[ 0.195518] Modules linked in:
[ 0.195531] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.1.5+11-ph #1
[ 0.195535] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[ 0.195544] ffffffff819fc200 ffff88023fc43e88 ffffffff8162dd36
000000000000121a
[ 0.195551] ffff88023fc43ed8 ffff88023fc43ec8 ffffffff8107dcb7
ffff88023fc43ea8
[ 0.195558] 0000000000000000 0000000000000001 ffffffff81e667c0
ffffffff81cf1540
[ 0.195564] Call Trace:
[ 0.195568] <IRQ> [<ffffffff8162dd36>] dump_stack+0x45/0x57
[ 0.195591] [<ffffffff8107dcb7>] warn_slowpath_common+0x97/0xe0
[ 0.195596] [<ffffffff8107ddb6>] warn_slowpath_fmt+0x46/0x50
[ 0.195600] [<ffffffff810f08c1>] can_stop_full_tick+0x1c1/0x200
[ 0.195604] [<ffffffff810f0c87>] tick_nohz_irq_exit+0x97/0xd0
[ 0.195609] [<ffffffff81081c3d>] irq_exit+0xcd/0x130
[ 0.195620] [<ffffffff8103aeaa>] smp_apic_timer_interrupt+0x4a/0x60
[ 0.195627] [<ffffffff816351fe>] apic_timer_interrupt+0x6e/0x80
[ 0.195631] <EOI> [<ffffffff81132e87>] ?
trace_event_enum_update+0x1c7/0x3b0
[ 0.195644] [<ffffffff81132ecc>] ? trace_event_enum_update+0x20c/0x3b0
[ 0.195649] [<ffffffff81d77d01>] ? stop_trace_on_warning+0x3f/0x3f
[ 0.195654] [<ffffffff81d77e1b>] tracer_init_tracefs+0x11a/0x23b
[ 0.195661] [<ffffffff81000328>] do_one_initcall+0xd8/0x210
[ 0.195669] [<ffffffff8109b700>] ? parse_args+0x1b0/0x450
[ 0.195676] [<ffffffff810c0d23>] ? __wake_up+0x53/0x70
[ 0.195684] [<ffffffff81d5a265>] kernel_init_freeable+0x178/0x20f
[ 0.195689] [<ffffffff81d5997d>] ? do_early_param+0x8c/0x8c
[ 0.195700] [<ffffffff811c76c2>] ? create_pipe_files+0x1f2/0x200
[ 0.195706] [<ffffffff8161f6a0>] ? rest_init+0x80/0x80
[ 0.195711] [<ffffffff8161f6ae>] kernel_init+0xe/0xf0
[ 0.195715] [<ffffffff816347a2>] ret_from_fork+0x42/0x70
[ 0.195719] [<ffffffff8161f6a0>] ? rest_init+0x80/0x80
[ 0.195729] ---[ end trace cf665146248feec1 ]---
Stefan
Am 15.08.2015 um 20:44 schrieb Stefan Priebe:
Hi,
while switching to a FULL tickless kernel i detected that all our VMs
produce the following stack trace while running under qemu 2.3.0.
[ 0.195160] HPET: 3 timers in total, 0 timers will be used for
per-cpu timer
[ 0.195181] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0
[ 0.195188] hpet0: 3 comparators, 64-bit 100.000000 MHz counter
[ 0.200119] Switched to clocksource hpet
[ 0.201164] ------------[ cut here ]------------
[ 0.201193] WARNING: CPU: 1 PID: 1 at kernel/time/tick-sched.c:192
can_stop_full_tick+0x1c1/0x200()
[ 0.201199] NO_HZ FULL will not work with unstable sched clock
[ 0.201203] Modules linked in:
[ 0.201214] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.18.20+55-ph #1
[ 0.201219] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org
04/01/2014
[ 0.201226] 0000000000000009 ffff88023fc43e88 ffffffff815f5889
00000000000008df
[ 0.201230] ffff88023fc43ed8 ffff88023fc43ec8 ffffffff8107433c
ffff88023fc43ea8
[ 0.201233] 0000000000000000 0000000000000001 ffff880236c41300
00000000cbbde78b
[ 0.201237] Call Trace:
[ 0.201240] <IRQ> [<ffffffff815f5889>] dump_stack+0x46/0x58
[ 0.201260] [<ffffffff8107433c>] warn_slowpath_common+0x8c/0xc0
[ 0.201264] [<ffffffff81074426>] warn_slowpath_fmt+0x46/0x50
[ 0.201270] [<ffffffff810ddc31>] can_stop_full_tick+0x1c1/0x200
[ 0.201274] [<ffffffff810ddfc7>] tick_nohz_irq_exit+0x97/0xd0
[ 0.201277] [<ffffffff81077f0d>] irq_exit+0xcd/0x130
[ 0.201286] [<ffffffff8103419a>] smp_apic_timer_interrupt+0x4a/0x60
[ 0.201293] [<ffffffff815fc4ea>] apic_timer_interrupt+0x6a/0x70
[ 0.201296] <EOI> [<ffffffff811bc1d5>] ? __d_lookup+0x55/0x160
[ 0.201309] [<ffffffff811bc315>] d_lookup+0x35/0x60
[ 0.201312] [<ffffffff811adc1b>] lookup_dcache+0x3b/0xd0
[ 0.201315] [<ffffffff811adcd3>] __lookup_hash+0x23/0x50
[ 0.201319] [<ffffffff811aeaae>] lookup_one_len+0xce/0x120
[ 0.201328] [<ffffffff812d062f>] __create_file+0x8f/0x260
[ 0.201332] [<ffffffff812d089b>] debugfs_create_dir+0x1b/0x20
[ 0.201338] [<ffffffff8111d9a8>] event_create_dir+0x68/0x520
[ 0.201342] [<ffffffff81d5bdb0>] event_trace_init+0x188/0x210
[ 0.201348] [<ffffffff81113e1b>] ? trace_create_file+0x1b/0x50
[ 0.201352] [<ffffffff81d5bc28>] ? event_trace_enable+0x1a2/0x1a2
[ 0.201359] [<ffffffff81000328>] do_one_initcall+0xd8/0x200
[ 0.201368] [<ffffffff81090200>] ? parse_args+0x1f0/0x470
[ 0.201373] [<ffffffff810b1c33>] ? __wake_up+0x53/0x70
[ 0.201378] [<ffffffff81d3e1ce>] kernel_init_freeable+0x168/0x1ff
[ 0.201381] [<ffffffff81d3d917>] ? do_early_param+0x8c/0x8c
[ 0.201389] [<ffffffff812f0680>] ? cryptomgr_probe+0x60/0xe0
[ 0.201398] [<ffffffff815e6f30>] ? rest_init+0x80/0x80
[ 0.201401] [<ffffffff815e6f3e>] kernel_init+0xe/0xf0
[ 0.201405] [<ffffffff815fb708>] ret_from_fork+0x58/0x90
[ 0.201408] [<ffffffff815e6f30>] ? rest_init+0x80/0x80
[ 0.201415] ---[ end trace a15ba3bc1d247b4c ]---
Stefan