I just finished setting up a fresh HHVM + REDIS installation. Was super easy and works much better out-of-the box then when I used fcgi caching. I have tested updating content and cache was purged directly. Also tested with different browsers, to see if a cached page was served to browser B when visited before on browser A. All worked just fine.
Also loving the speed! Without caching the TTFB is around 80ms. Cached its about 30ms. Happy camper!
But… Im having caching issues when using woocommerce. Here I found some info concerning fcgi caching:
Anybody knows how to properly config the REDIS setup? And does anyone know if the redis caching support block caching? i.e. caching everything but the cart DIV on a page?