How Java program divided between CPUs (in multi CPUs systems)

Question

I start Java my Java application on system with 16 CPUs, but mostly loads on first CPU. Is it normal? If not, how can I repair it?

top - 18:40:52 up 42 days, 22:18,  2 users,  load average: 8.36, 11.87, 15.61
Tasks: 214 total,   2 running, 212 sleeping,   0 stopped,   0 zombie
Cpu0  : 42.3%us,  1.7%sy,  0.0%ni, 52.0%id,  0.0%wa,  0.0%hi,  4.0%si,  0.0%st
Cpu1  :  6.3%us,  0.7%sy,  0.0%ni, 63.8%id, 29.2%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  : 13.0%us,  0.7%sy,  0.0%ni, 63.2%id, 23.1%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu3  :  6.6%us,  1.0%sy,  0.0%ni, 66.9%id, 25.5%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu4  : 14.7%us,  0.3%sy,  0.0%ni, 61.3%id, 23.7%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu5  :  7.0%us,  1.0%sy,  0.0%ni, 66.4%id, 25.6%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu6  : 15.3%us,  0.7%sy,  0.0%ni, 61.1%id, 22.9%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu7  :  6.0%us,  1.7%sy,  0.0%ni, 52.5%id, 39.9%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu8  : 33.2%us,  1.0%sy,  0.0%ni, 46.5%id, 19.3%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu9  :  6.0%us,  1.0%sy,  0.0%ni, 67.0%id, 26.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu10 : 12.3%us,  0.3%sy,  0.0%ni, 62.0%id, 25.3%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu11 :  6.6%us,  1.0%sy,  0.0%ni, 73.4%id, 18.9%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu12 : 15.9%us,  0.7%sy,  0.0%ni, 60.8%id, 22.6%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu13 :  8.0%us,  1.0%sy,  0.0%ni, 61.8%id, 29.2%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu14 : 10.6%us,  0.3%sy,  0.0%ni, 65.9%id, 23.2%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu15 :  3.0%us,  1.0%sy,  0.0%ni, 70.4%id, 25.6%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   4037612k total,  4020856k used,    16756k free,    13164k buffers
Swap:  5859064k total,      260k used,  5858804k free,  2275596k cached

Thanks!

Answer 1

There are pretty high values of %wa for the other CPU's, which might suggest that some disk access or similar thing is the bottleneck. You need to provide much more detail about your application though...

Answer 2

Is your application single-threaded? If so you will need to redesign your application to make use of additional CPUs.