How to optimize MySQL settings?

[Jason Long]

Hello,
My server has 6 GB RAM and 4 virtual CPUs. MySQL uses a lot of RAM and CPU on my server compared to other programs. My MySQL configuration is:

[mysqld]
performance_schema = 0
show_compatibility_56 = 1
datadir = /var/lib/mysql
socket = /var/lib/mysql/mysql.sock
slow-query_log_file = /var/log/mysql-slow.log
log-error = /var/log/mysqld.log
max_allowed_packet=268435456
default_storage_engine = InnoDB
max_connections = 151
max_user_connections = 50
thread_cache_size = 151
query_cache_type = 1
query_cache_size = 64M
sort_buffer_size = 2M
tmp_table_size = 32M
read_buffer_size = 128k
read_rnd_buffer_size = 256k
join_buffer_size = 128k
table_definition_cache = 400
table_open_cache = 400

slow_query_log_file = slow.log
slow_query_log = 0
log_queries_not_using_indexes = 1
long_query_time = 0.5
min_examined_row_limit = 100

max_heap_table_size = 64M

innodb_buffer_pool_size = 10M
innodb_file_per_table = 1
innodb_flush_log_at_trx_commit = 2
innodb_log_buffer_size = 8M
innodb_log_file_size = 100M

log_bin
expire_logs_days = 7


Which part of the settings is wrong?

Thank you.