>This is PHP, though, and you would have to jump through a lot of hoops to remove the IO overhead. At least HipHop uses libevent, so at least apps won't be blocked by slow clients anymore.
Really, in PHP you don't have to jump through many hoops at all to minimize disk I/O. Employ APC opcode and user variable caching, build PHP's Memcached (with the 'd' on the end, not the old 'Memcache' lib) into your data layer, and you're good to go.
If you're letting any process sit idle, much less a '100-400 MB' one, you're doing it wrong--in any language.
Really, in PHP you don't have to jump through many hoops at all to minimize disk I/O. Employ APC opcode and user variable caching, build PHP's Memcached (with the 'd' on the end, not the old 'Memcache' lib) into your data layer, and you're good to go.
If you're letting any process sit idle, much less a '100-400 MB' one, you're doing it wrong--in any language.