ApacheCon 2016

Virtual Memory (VM) systems allow you to map a virtual memory space onto a, typically smaller, physical memory space. This is usually done with the assistance of a Memory Management Unit (MMU). The MMU breaks the memory space up into units of "pages" and keeps a very small very fast hardware cache (TLB) of the virtual to physical mappings (page table). Traditionally the pages are relatively small (4KiB) compared with today's physical memory sizes (100's of GiB). Because the page cache is so small (10's to 1000's of entries, depending on the architecture), applications with large heap sizes often cause thrashing of this cache. To combat this, most modern processors offer alternate larger pages sizes. They are most commonly referred to as huge pages. This talk will be about the usage of huge pages inside Apache Traffic Server, some real world results, and future direction.