Linux schedulers in tpcc like benchmark

I mentioned earlier that IO scheduler CFQ coming by default in RedHat / CentOS 5.x may be not so good for MySQL. And yesterday one customer reported that just changing cfq to noop solved their InnoDB IO problems. I ran tpcc scripts against XtraDB on our Dell PowerEdge R900 server (16 cores, 8 disks in RAID10, controller Perc/6i with BBU) to compare cfq, deadline, noop and anticipatory (last one just to get number, I did not expect a lot from anticipatory).

Here is result (in transactions per minute, more is better):

cfq	2793.5
noop	6586.4
deadline	6513.7
anticipatory	1465

Here is graph of disk writes (column bo in vmstat) during benchmark

As you see noop / deadline can utilize disks much better.

For reference I used tpcc scripts from https://launchpad.net/perconatools, generated 100W (about 9.5GB of data on disk), and used next XtraDB params:

Shell

[mysqld] #mysqld options in alphabetical order user=root  default_table_type=MYISAM  innodb_buffer_pool_size=3G innodb_data_file_path=ibdata1:10M:autoextend innodb_file_per_table=1 innodb_flush_log_at_trx_commit=1 innodb_log_buffer_size=8M innodb_log_files_in_group=2 innodb_log_file_size=128M innodb_thread_concurrency=0 innodb_flush_method             = O_DIREC  innodb_write_io_threads=4 innodb_read_io_threads=4 innodb_io_capacity=800 innodb_adaptive_checkpoint=1  max_connections=3000 query_cache_size=0 skip-name-resolve  table_cache=2048

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