Mysql 100% 1 carga do CPU principal

Question

Eu tenho 8 cpu no servidor, e o Mysql funciona apenas em 1 cpu core em 100%.

Como posso usar todos os núcleos?

meu my.cnf

[mysqld]
safe-show-database
query_cache_limit=1M
query_cache_size=64M ## 32MB for every 1GB of RAM
query_cache_type=1
max_user_connections=200
max_connections=400
thread_cache=16
thread_cache_size=128
key_buffer=256M ## 128MB for every 1GB of RAM
key_buffer_size=280MB #30% RAM
join_buffer=1M
max_connect_errors=20
max_allowed_packet=16M
table_cache=1024
record_buffer=1M
sort_buffer_size=2M ## 1MB for every 1GB of RAM
read_buffer_size=2M ## 1MB for every 1GB of RAM
read_rnd_buffer_size=2M  ## 1MB for every 1GB of RAM
thread_concurrency=16 ## Number of CPUs x 2
innodb_file_per_table
#innodb_thread_concurrency=8 ## Number of CPUs x 2
myisam_sort_buffer_size=64M
log_slow_queries=/var/log/mysql-slow-queries.log
long_query_time=20
interactive_timeout=20
#wait_timeout=57600
wait_timeout=100000
net_read_timeout=400
net_write_timeout=600
connect_timeout=20
delayed_insert_timeout=10
local-infile=0

log-warnings=2
log-error=/var/log/mysql_err.log
max_allowed_packet=32M

############
#log-bin=master1-bin
#expire_logs_days = 10 # purge binary log after 10 days
#max_binlog_size = 1024M
############
#log = /var/log/mysql.log

[mysql.server]
user=mysql

[safe_mysqld]
open_files_limit=8192

[mysqldump]
quick
max_allowed_packet=16M