Memory management fpm/whm question

Just trying to get your thoughts on how memory is managed.

I have zend installed , and from looking at your ‘opcache usage’ it matches to my zend settings. So I’m confident it’s using zend opcache.

default zend settings – other than
opcache.memory_consumption=256

I’m use php-fpm from whm.

Each site is launched from a different user, each with say 8 php-fpm workers.

eg.
https://www.mysite.com – user:mysite, 8 fpm workers
https://www.myshop.com – user:myshoop , 8 fpm workers.

So my guess is:
– it’s using mmap – 256Mb
– linux stops each user account from seeing the shared memory of other users – regardless of cache salt
– 1 chunk of mmap per user(aka site) using mmap of 256mb
– but each of the php-fpm workers can access the shared 256mb
– so say 8 sites, each with 8 workers, it’s 2gb of RAM (8x256mb).

; Enable Zend OPcache extension module
zend_extension=opcache.so

; Determines if Zend OPCache is enabled
opcache.enable=1

; Determines if Zend OPCache is enabled for the CLI version of PHP
;opcache.enable_cli=0

; The OPcache shared memory storage size.
opcache.memory_consumption=256

; The amount of memory for interned strings in Mbytes.
opcache.interned_strings_buffer=8

; The maximum number of keys (scripts) in the OPcache hash table.
; Only numbers between 200 and 100000 are allowed.
opcache.max_accelerated_files=4000

; The maximum percentage of "wasted" memory until a restart is scheduled.
;opcache.max_wasted_percentage=5

; When this directive is enabled, the OPcache appends the current working
; directory to the script key, thus eliminating possible collisions between
; files with the same name (basename). Disabling the directive improves
; performance, but may break existing applications.
;opcache.use_cwd=1

; When disabled, you must reset the OPcache manually or restart the
; webserver for changes to the filesystem to take effect.
;opcache.validate_timestamps=1

; How often (in seconds) to check file timestamps for changes to the shared
; memory storage allocation. ("1" means validate once per second, but only
; once per request. "0" means always validate)
;opcache.revalidate_freq=2

; Enables or disables file search in include_path optimization
;opcache.revalidate_path=0

; If disabled, all PHPDoc comments are dropped from the code to reduce the
; size of the optimized code.
;opcache.save_comments=1

; If enabled, a fast shutdown sequence is used for the accelerated code
;opcache.fast_shutdown=0

; Allow file existence override (file_exists, etc.) performance feature.
;opcache.enable_file_override=0

; A bitmask, where each bit enables or disables the appropriate OPcache
; passes
;opcache.optimization_level=0xffffffff

;opcache.inherited_hack=1
;opcache.dups_fix=0

; The location of the OPcache blacklist file (wildcards allowed).
; Each OPcache blacklist file is a text file that holds the names of files
; that should not be accelerated.
opcache.blacklist_filename=/opt/cpanel/ea-php74/root/etc/php.d/opcache*.blacklist

; Allows exclusion of large files from being cached. By default all files
; are cached.
;opcache.max_file_size=0

; Check the cache checksum each N requests.
; The default value of "0" means that the checks are disabled.
;opcache.consistency_checks=0

; How long to wait (in seconds) for a scheduled restart to begin if the cache
; is not being accessed.
;opcache.force_restart_timeout=180

; OPcache error_log file name. Empty string assumes "stderr".
;opcache.error_log=

; All OPcache errors go to the Web server log.
; By default, only fatal errors (level 0) or errors (level 1) are logged.
; You can also enable warnings (level 2), info messages (level 3) or
; debug messages (level 4).
;opcache.log_verbosity_level=1

; Preferred Shared Memory back-end. Leave empty and let the system decide.
;opcache.preferred_memory_model=

; Protect the shared memory from unexpected writing during script execution.
; Useful for internal debugging only.
;opcache.protect_memory=0

; Allows calling OPcache API functions only from PHP scripts which path is
; started from specified string. The default "" means no restriction
;opcache.restrict_api=

; Enables and sets the second level cache directory.
; It should improve performance when SHM memory is full, at server restart or
; SHM reset. The default "" disables file based caching.
; RPM note : file cache directory must be owned by process owner
;   for mod_php, see /etc/httpd/conf.d/php.conf
;   for php-fpm, see /etc/php-fpm.d/*conf
opcache.file_cache=""

; Enables or disables opcode caching in shared memory.
;opcache.file_cache_only=0

; Enables or disables checksum validation when script loaded from file cache.
;opcache.file_cache_consistency_checks=1

; Enables or disables copying of PHP code (text segment) into HUGE PAGES.
; This should improve performance, but requires appropriate OS configuration.
opcache.huge_code_pages=0

; Leads OPcache to check file readability on each access to cached file.
; This directive should be enabled in shared hosting environment, when few
; users (PHP-FPM pools) reuse the common OPcache shared memory.
opcache.validate_permission=1