InnoDB memory usage

There are many questions how InnoDB allocates memory. I’ll try to give some explanation about the memory allocation at startup.
Some important constants:
NBLOCKS=count of block in innodb_buffer_pool = innodb_buffer_pool_size / 16384
OS_THREADS= if (innodb_buffer_pool_size >= 1000Mb) = 50000
else if (innodb_buffer_pool_size >= 8Mb) = 10000
else = 1000 (it’s true for *nixes, for Windows there is a bit another calculation for OS_THREADS)
So InnoDB uses:

• innodb_buffer_pool
• innodb_additional_mem_pool_size
• innodb_log_buffer_size
• adaptive index hash, size= innodb_buffer_pool / 64
• system dictionary hash, size = 6 * innodb_buffer_pool_size / 512
• memory for sync_array, which is used for syncronization primitives, size = OS_THREADS * 152
• memory for os_events, which are also used for syncronization primitives, OS_THREADS * 216
• and memory for locking system, size=5 * 4 * NBLOCKS

So the final formula for innodb:
innodb_buffer_pool_size + innodb_log_buffer_size + innodb_additional_mem_pool_size + 812 / 16384 * innodb_buffer_pool_size + OS_THREADS * 368

For simplicity we can use: 812 / 16384 * innodb_buffer_pool_size ~~ innodb_buffer_pool_size / 20
and OS_THREADS*368 = 17.5MB if innodb_buffer_pool > 1000MB
= 3.5MB if > 8MB

For example if you have innodb_buffer_pool_size=1500M, innodb_additional_mem_pool_size = 20M, innodb_log_buffer_size = 8M, InnoDB will allocate = 1500M + 20M + 8M + 1500/20M + 17.5M = 1620.5M.
Take the additional memory into account when you are planning memory usage for your server.