very very high cpu load
Hello!
I have a same problem.
Server: linux localhost.localdomain 2.6.18-194.26.1.el5.028stab070.14 #1 SMP Thu Nov 18 16:34:01 MSK 2010 i686 i686 i386 GNU/Linux, OS centos 5.5, mysql Ver 14.12 Distrib 5.0.77, the database size is 60mb [mysql in OPENVZ]; [Hardware Node] 16Gb ram, 2 x CPUX5650.
and it was a problem at performance (frequency of query is less 300 per sec, SELECT - 95%): it's too high a SYSTEM TIME 50-70%, iowait = 0% and user time is 10-20%.
mysql cache/buffer is too bigger.
strace -c -f -p 20227 [attach to mysql server]
Process 20227 attached with 19 threads - interrupt to quit
Process 29812 attached
Process 20227 detached
Process 20230 detached
Process 20431 detached
Process 21537 detached
Process 21538 detached
Process 21546 detached
Process 21548 detached
Process 21642 detached
Process 21895 detached
Process 21896 detached
Process 21897 detached
Process 21898 detached
Process 21899 detached
Process 21900 detached
Process 21901 detached
Process 21902 detached
Process 21903 detached
Process 21905 detached
Process 21906 detached
Process 29812 detached
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
54.48 23.852838 29 833162 307252 futex
17.93 7.849934 42 185320 4549 read
12.12 5.306598 7792 681 select
11.10 4.860252 540028 9 rt_sigtimedwait
2.88 1.259689 39 32013 33 write
0.61 0.266179 2 151460 pread64
0.45 0.197203 1 158977 _llseek
0.11 0.047907 2 31172 gettimeofday
0.07 0.028954 1 21555 21555 sched_setscheduler
0.06 0.025613 12 2191 pwrite64
0.06 0.025517 2 12565 fcntl64
0.06 0.024217 1 16843 time
0.02 0.007814 5 1444 munmap
0.01 0.004483 3 1320 mmap2
0.01 0.004209 2 1835 197 setsockopt
0.01 0.003666 5 681 accept
0.01 0.003567 5 692 shutdown
0.01 0.002926 6 465 mprotect
0.01 0.002681 4 759 brk
0.01 0.002541 5 463 madvise
0.00 0.001917 3 681 getsockname
0.00 0.001458 2 610 access
0.00 0.000773 2 479 getpeername
0.00 0.000738 1 692 close
0.00 0.000000 0 9 alarm
0.00 0.000000 0 1 clone
0.00 0.000000 0 18 rt_sigprocmask
0.00 0.000000 0 7 tgkill
0.00 0.000000 0 1 set_robust_list
------ ----------- ----------- --------- --------- ----------------
100.00 43.781674 1456105 333586 total
top
Tasks: 180 total, 2 running, 178 sleeping, 0 stopped, 0 zombie
Cpu0 : 9.6%us, 53.0%sy, 0.0%ni, 37.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 9.1%us, 42.0%sy, 0.0%ni, 48.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu2 : 8.6%us, 18.3%sy, 0.0%ni, 73.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu3 : 12.1%us, 31.9%sy, 0.0%ni, 56.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu4 : 10.8%us, 81.1%sy, 0.0%ni, 8.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu5 : 14.6%us, 36.0%sy, 0.0%ni, 49.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu6 : 13.4%us, 58.5%sy, 0.0%ni, 28.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu7 : 11.8%us, 49.4%sy, 0.0%ni, 38.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu8 : 9.9%us, 48.1%sy, 0.0%ni, 42.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu9 : 17.0%us, 34.1%sy, 0.0%ni, 48.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu10 : 13.8%us, 42.5%sy, 0.0%ni, 43.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu11 : 11.8%us, 43.5%sy, 0.0%ni, 44.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu12 : 6.1%us, 4.1%sy, 0.0%ni, 89.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu13 : 7.4%us, 59.3%sy, 0.0%ni, 33.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu14 : 7.3%us, 53.7%sy, 0.0%ni, 39.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu15 : 11.2%us, 73.8%sy, 0.0%ni, 15.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu16 : 10.0%us, 43.3%sy, 0.0%ni, 46.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu17 : 14.6%us, 20.2%sy, 0.0%ni, 58.4%id, 6.7%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu18 : 16.9%us, 55.4%sy, 0.0%ni, 27.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu19 : 10.8%us, 25.8%sy, 0.0%ni, 63.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu20 : 10.8%us, 55.4%sy, 0.0%ni, 33.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu21 : 7.9%us, 73.7%sy, 0.0%ni, 18.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu22 : 7.5%us, 19.4%sy, 0.0%ni, 73.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu23 : 13.9%us, 54.4%sy, 0.0%ni, 31.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2800000k total, 995772k used, 1804228k free, 0k buffers
Swap: 0k total, 0k used, 0k free, 0k cached
what's kind of the problem could be linked with so huge kernel's load?
the problem comes only then mysql is load too much.
thank you.
Edited 2 time(s). Last edit at 08/11/2011 08:51AM by loginrl103 asd.