High CPU usage on server by MySQL on AWS ubuntu server - php

Question

MySQL showing very high CPU usage. like over 200% sometime.
I had slow query log on. and slow query time set to 1s.
there is not any slow query.
I am using code igniter PHP.
my my.cnf file :
[mysqld]
innodb_io_capacity=2000
innodb_read_io_threads=32
innodb_write_io_threads=32
innodb_log_buffer_size=250M
innodb_thread_concurrency=0
innodb_buffer_pool_size=1000M
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
##
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
#
# * Fine Tuning
#
innodb_buffer_pool_size = 12G
key_buffer_size = 1G
max_allowed_packet = 256M
thread_stack = 192K
thread_cache_size = 100
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover-options = BACKUP
max_connections = 300
#innodb_buffer_pool_instances=8
#innodb_read_io_threads=8
#innodb_write_io_threads=8
#open_files_limit = 1024
#table_open_cache = 400
server_id = 2
bind-address = 0.0.0.0
log_bin = /var/log/mysql/mysql-bin.log
log_bin_index = /var/log/mysql/mysql-bin.log.index
relay_log = /var/log/mysql/mysql-relay-bin
relay_log_index = /var/log/mysql/mysql-relay-bin.index
expire_logs_days = 10
max_binlog_size = 100M
log_slave_updates = 1
auto-increment-increment = 2
auto-increment-offset = 2
replicate-ignore-db=phpmyadmin
replicate-ignore-db=mysql
skip-name-resolve
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit=0
query_cache_size=0
sort_buffer_size = 2M
join_buffer_size = 128K
read_buffer_size = 128K
read_rnd_buffer_size=256K
what can I do to reduce CPU usage?
Is there any way to find which queryes are causing high cpu usage o

Answer 1

there is not any slow query
There aren't any slow queries, or there aren't any slow queries showing in the log? I think your first prt of call would be to check if the query logging is working as you expect. This can be done easily using discretionary locks without adding additional load on the system.
Assuming that there really are no queries taking over 1 second, then the load arises fro lots of queries taking less than 1 second. You need to capture them all to identify and prioritize your tuning efforts. But you might start by enabling the query cache (which you have disabled for some reason).