HHVM (HipHop Virtual Machine) vs PHP-FPM: What are the differences?
HHVM (HipHop Virtual Machine): An open-source virtual machine designed for executing programs written in Hack and PHP. HHVM uses a just-in-time (JIT) compilation approach to achieve superior performance while maintaining the flexibility that PHP developers are accustomed to. To date, HHVM (and its predecessor HPHPc before it) has realized over a 9x increase in web request throughput and over a 5x reduction in memory consumption for Facebook compared with the PHP 5.2 engine + APC; PHP-FPM: * An alternative FastCGI daemon for PHP*. It is an alternative PHP FastCGI implementation with some additional features useful for sites of any size, especially busier sites. It includes Adaptive process spawning, Advanced process management with graceful stop/start, Emergency restart in case of accidental opcode cache destruction etc.
HHVM (HipHop Virtual Machine) belongs to "Virtual Machine" category of the tech stack, while PHP-FPM can be primarily classified under "Background Processing".
HHVM (HipHop Virtual Machine) is an open source tool with 16.1K GitHub stars and 2.87K GitHub forks. Here's a link to HHVM (HipHop Virtual Machine)'s open source repository on GitHub.
According to the StackShare community, HHVM (HipHop Virtual Machine) has a broader approval, being mentioned in 44 company stacks & 72 developers stacks; compared to PHP-FPM, which is listed in 9 company stacks and 8 developer stacks.