memory_get_peak_usage
    (no version information, might be only in CVS)
memory_get_peak_usage -- Returns the peak of memory allocated by PHP
Description
int 
memory_get_peak_usage ( void  )
   Returns the peak of memory, in bytes, that's been allocated to your PHP
   script.
  
   memory_get_peak_usage() will only be defined if your PHP
   is compiled with the --enable-memory-limit 
   configuration option.