I have large photo file and would like to use gwan as it fast. Is there any performance benefits in comparison to nginx fast-cgi. Does gwan fast at timd to first byte? Is it faster at connecting time? Is commputing time faster? Is throughput faster?Furthermore can you install hhvm on gwan. If you can, how would you install hhvm?would it give a performance benefit to php(how much)?
The downside of FasCGI is that it's itself a backend server: instead of having only G-WAN as a server, you are limited by the speed of the backend server when G-WAN sends it requests and waits its replies:
Internet LAN
[clients] ============ [G-WAN] ----------------- [FastCGI + PHP]
latency1 latency2 latency3 latency4 latency5
In this case, the latency of a FastCGI server and the extra LAN latency are slowing-down G-WAN.
A more efficient way is to have G-WAN load and run the HHVM itself, which has been done with PH7, another thread-safe PHP runtime provided with G-WAN v4+:
Internet
[clients] ============ [G-WAN + PHP]
latency1 latency2 latency3
It is technically possible to implement *.hhvm G-WAN scripts like it has been done for G-WAN *.ph7, *.java, *.scala and *.cs (C#) scripts. This requires writting a G-WAN C module to load the HHVM in the G-WAN memory-sapce (something that may take time depending on the level of support provided by the Facebook HHVM team).
One could also use the G-WAN CGI interface to invoke HHVM as a local process (like G-WAN was forced to do for the thread-unsafe Zend PHP). But the results in terms of performance greatly depend on the initialization and processing times of the HHVM executable (not to mention the extra per-request overhead). This third way is simpler to implement but necessarily slower than a native HHVM G-WAN module.
The only way you are going to know if nginx or G-WAN are better for your use case is to actually use them for your site and benchmark it. The speed of software like this depend very much on your configuration, usage patterns, site structure, etc etc, and is not something where a single blanket answer is appropriate or useful.
HHVM can be used behind any webserver which can serve FastCGI requests. A quick google search indicates that G-WAN may not support FastCGI, but rather has its own custom scripting interface? If so, it may still be possible to use that interface to integrate HHVM, though it is likely to require some work and not be officially supported.