APCSome useful tuning

2 caching mechanism

Memory cache for long operations and calculations

Opcode cache for skipping code interpretation

Opcode

The Vulcan Logic Disassembler

Tuning opcode cache

apc.max_file_size (1M)Files bigger then that wouldn't be cached.

apc.num_files_hint (1000)Number of files that will be cached. Increase it.

apc.file_md5 (0)Keep it 0, it's a lie

apc.ttl (0)How long the file will stay cached

Tuning opcode cache

apc.stat (1)Rechecking if file was updated. Set it to 0.

Tuning opcode cache

strace -e trace=file httpd -X

Tuning opcode cache

apc.stat (1)Rechecking if file was updated. Set it to 0.

apc.slam_defense (1)Prevents mass caching on startup. Set to 0

apc.write_lock (1)Prevents locking of parallel requests

apc.file_update_protection (2)Seconds to wait before new file gets cached

Extra control on opcode caching

apc.filter (null)Regexp: cache only matching it files.

apc.cache_by_default (1)Caches all php files. If set to 0 - it would use the filter

apc.canonicalize (1)Convert relative path's into canonical. Set to 0 and always use absolute path's.

Now User Cache

Concurrent lockingFile locksBasic locking mechanism. Very slow.

IPC Semaphore locksSemaphores (provided by the OS). Better then file locks

Linux Futex locksLinux specific mechanism. Significant gain. ( user space )

Pthread mutexesAlmost same as futex ( kernel space)

Spin locksExtremely fast. Ported from Postgres. Eats your cpu

Use igbinarySerialization sucksExample array: [1,2,'hi']

Use igbinary

Apc constants

Regular defines are uber slow

Prime cache before start

Preload cache with data before going public

apc_store()apc_compile_file()