Messages in this thread | | | Date | Tue, 09 May 2017 10:53:25 +0300 | From | mitko@stz-bg ... | Subject | Re: BUG: rcu_sched detected stalls on CPUs |
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On 2017-05-08 16:24, Paul E. McKenney wrote: > On Mon, May 08, 2017 at 09:43:15AM +0300, mitko@stz-bg.com wrote: >> On 2017-01-20 17:19, Steven Rostedt wrote: >> >On Fri, 20 Jan 2017 10:43:50 +0200 >> >mitko@stz-bg.com wrote: >> > >> >>[1.] One line summary of the problem: >> >> >> >>rcu_sched detected stalls on CPUs and few minutes server not respond. >> > >> >Is this reproducible? Or was this a one time ordeal? >> > >> >> >> >>[2.] Full description of the problem/report: >> >> >> >>Load of my server (postgres database) isnt big less then 0.50 and when >> >>error occured rcu_sched detected stalls on CPUs >> >>server freeze and nothing is work for 3-5 minute. >> >>No network, no video signal, no keyboard, no mouse. Nothing is worked. >> >>After these few minutes everything continue normal. >> >>This usual is happend once per day. When I check in google find a lots >> >>of ppl complain of this error, but no solution. >> >>Do any one know can help me to resolve it ? I spoke with few >> >>friends and >> >>they trying to convince me the problem is in CPU. >> >>I did not believe after a 3 years working CPU suddenly stop working >> >>correctly, but I might be wrong. >> >> >> >>[3.] Keywords (i.e., modules, networking, kernel): >> >> >> >>kernel >> >> >> >>[4.] Kernel information >> >>[4.1.] Kernel version (from /proc/version): >> >> >> >>Linux version 4.4.38 (root@hive64) (gcc version 5.4.0 (GCC) ) #2 >> >>SMP Sun >> >>Dec 11 16:11:02 CST 2016 >> >> >> > >> >Have you tried a newer version of the kernel? >> > >> >-- Steve >> >> >> Hello, >> yesterday I change to new kernel: 4.9.26 and still no effect. >> >> I trying to figure out what I need to buy because I read on google a >> lots of posts about that problem, >> some ppl suggest is BIOS firmware bug, some ppl tell that when they >> swap CPU problem is resolved. >> May be problem was started when I first time boot 4.x kernel and >> there have cpu microcode updates. >> Im 3.x kernels this feature was not in kernel, but I don't know, >> only guess. >> >> Can some one point me clearly: You need to change this one and >> problem will be solved ? > > Looking back at your earlier email, I see the following: > > [Wed Jan 4 10:19:12 2017] rcu_sched kthread starved for 60004 > jiffies! g61967937 c61967936 f0x0 s3 ->state=0x1 > > That indicates that the task "rcu_sched" isn't being allowed to run. > The "->state=0x1" indicates that this task is currently asleep and the > "s3" indicates that it is looking to start a grace period, but has not > progressed through this task. My guess is that your system get very > busy, and that rcu_sched's normal scheduling priority is not sufficient > for it to be allowed to run. > > I therefore suggest that you try raising the rcu_sched task's priority. > > You can find this task like this: > > ps -ef | grep rcu_sched > > On my laptop, I get this: > > $ ps -ef | grep rcu_sched > root 7 2 0 Apr11 ? 00:19:19 [rcu_sched] > paulmck 18307 22926 0 06:11 pts/35 00:00:00 grep --color=auto > rcu_sche > > You can use the chrt command to set the priority. For example, given > that > on my laptop, rcu_sched is PID 7: > > sudo chrt -f -p 1 7 > > You can double-check as follows: > > $ chrt -p 7 > pid 7's current scheduling policy: SCHED_FIFO > pid 7's current scheduling priority: 1 > > Does that help? > > Thanx, Paul >
Hi, interesting ... I change priority as you suggest and will keep you in touch if the problem happens again because I cant reproduce it. Replay on your next email, I don't have any virtual servers / guest os on the server. It's server with only one process - redis server and in this time when error it's happened actually one of other servers start loading data into redis sever. Data is small 3-4 mil. keys every key contain around 150 symbols. I have that problem on two servers, next server is database server with postgresql and that problem happened more often, usual once per day or for few days. I never play before with changing priority of processes. When I check iLO log I saw logged error: power lost but server does not lost the power actually, it's just stop respond for 2-3 minutes and then continue normal operation with uptime more then 100 days.
Thanks for your suggestion. Regards, Mitko
>> [239940.067938] clocksource: timekeeping watchdog on CPU26: Marking >> clocksource 'tsc' as unstable because the skew is too large: >> [239940.067943] clocksource: 'hpet' wd_now: >> ecb521ce wd_last: ca45912d mask: ffffffff >> [239940.067946] clocksource: 'tsc' cs_now: >> 2d12df5f88d08 cs_last: 29fffbe2d36d6 mask: ffffffffffffffff >> [239940.068357] clocksource: Switched to clocksource hpet >> [240000.066457] INFO: rcu_sched detected stalls on CPUs/tasks: >> [240000.066488] 2-...: (38 GPs behind) idle=f1a/0/0 >> softirq=2417028/2417028 fqs=0 >> [240000.066491] 3-...: (27 GPs behind) idle=0bc/0/0 >> softirq=3076046/3076047 fqs=0 >> [240000.066494] 4-...: (1006 GPs behind) idle=308/0/0 >> softirq=1474922/1474922 fqs=0 >> [240000.066497] 5-...: (8034 GPs behind) idle=7b4/0/0 >> softirq=69165/69166 fqs=0 >> [240000.066499] 6-...: (1665 GPs behind) idle=716/0/0 >> softirq=16465/16465 fqs=0 >> [240000.066502] 7-...: (8034 GPs behind) idle=bd0/0/0 >> softirq=15923/15924 fqs=0 >> [240000.066505] 8-...: (1665 GPs behind) idle=a62/0/0 >> softirq=93861/93861 fqs=0 >> [240000.066507] 9-...: (1258 GPs behind) idle=a8c/0/0 >> softirq=21608/21608 fqs=0 >> [240000.066510] 11-...: (1665 GPs behind) idle=8e6/0/0 >> softirq=18844/18844 fqs=0 >> [240000.066512] 13-...: (1665 GPs behind) idle=ab8/0/0 >> softirq=21278/21278 fqs=0 >> [240000.066515] 14-...: (4854 GPs behind) idle=578/0/0 >> softirq=25624/25626 fqs=0 >> [240000.066517] 15-...: (8034 GPs behind) idle=f5e/0/0 >> softirq=18114/18115 fqs=0 >> [240000.066520] 16-...: (1665 GPs behind) idle=b66/0/0 >> softirq=19511/19511 fqs=0 >> [240000.066528] 17-...: (0 ticks this GP) idle=e18/0/0 >> softirq=16163/16163 fqs=0 >> [240000.066531] 18-...: (1665 GPs behind) idle=a18/0/0 >> softirq=16424/16424 fqs=0 >> [240000.066533] 19-...: (1665 GPs behind) idle=944/0/0 >> softirq=17920/17920 fqs=0 >> [240000.066549] 20-...: (20991 GPs behind) idle=750/0/0 >> softirq=17549/17552 fqs=0 >> [240000.066552] 21-...: (0 ticks this GP) idle=9e0/0/0 >> softirq=18937/18937 fqs=0 >> [240000.066555] 22-...: (14519 GPs behind) idle=95e/0/0 >> softirq=16122/16124 fqs=0 >> [240000.066557] 23-...: (1665 GPs behind) idle=bbc/0/0 >> softirq=16316/16316 fqs=0 >> [240000.066560] 24-...: (0 ticks this GP) idle=c56/0/0 >> softirq=20070/20070 fqs=0 >> [240000.066563] 27-...: (8034 GPs behind) idle=bdc/0/0 >> softirq=18291/18292 fqs=0 >> [240000.066566] 28-...: (8034 GPs behind) idle=4f8/0/0 >> softirq=22313/22314 fqs=0 >> [240000.066568] 29-...: (3443 GPs behind) idle=22a/0/0 >> softirq=24975/24976 fqs=0 >> [240000.066571] 30-...: (1665 GPs behind) idle=940/0/0 >> softirq=89382/89382 fqs=0 >> [240000.066572] (detected by 10, t=60002 jiffies, g=4843721, >> c=4843720, q=659) >> [240000.066578] Task dump for CPU 2: >> [240000.066581] swapper/2 R running task 0 0 >> 1 0x00200000 >> [240000.066588] 0000000000000083 ffffffffa5cecd79 ffff8aca3eea1e00 >> ffffffffa64cab40 >> [240000.066593] 0000000000000005 ffffffffa64cad38 ffffa96c80073eb0 >> ffffffffa5ba9d93 >> [240000.066597] ffff8aca3eea1e00 000000000e94fec6 ffff8aca38535940 >> 0000000000000002 >> [240000.066601] Call Trace: >> [240000.066617] [<ffffffffa5cecd79>] ? intel_idle+0x109/0x110 >> [240000.066625] [<ffffffffa5ba9d93>] ? >> cpuidle_enter_state+0x103/0x2b0 >> [240000.066629] [<ffffffffa5ba9f77>] ? cpuidle_enter+0x17/0x20 >> [240000.066638] [<ffffffffa50d5d73>] ? call_cpuidle+0x23/0x40 >> [240000.066641] [<ffffffffa50d5fd7>] ? cpu_startup_entry+0x147/0x220 >> [240000.066647] [<ffffffffa503ecfd>] ? start_secondary+0x12d/0x140 >> [240000.066650] Task dump for CPU 3: >> [240000.066651] swapper/3 R running task 0 0 >> 1 0x00200000 >> >> Regards, >> Mitko >>
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