Facebook's monster PHP engine ready to muscle into ARM server chips

Facebook has taken further steps in its quest to run production workloads on ARM-powered servers.

The smoking gun for this dramatic shift was a post by Facebook on the Hip Hop Virtual Machine blog on Thursday that indicated the team is implementing ARM processor support in its translation engine, which turns Facebook's PHP code into 64-bit x86 instructions to execute on compute nodes. The HHVM is Facebook's fundamental unit for running its mammoth PHP-based social network.

"It's also been crucial in our efforts to get hhvm running on ARM processors by isolating and reducing the amount of architecture-specific code we need to reimplement," Facebook wrote. "Watch for an upcoming post devoted to our ARM port for more details!"

The post came on the same day that Bloomberg claimed Google was planning a shift to ARM-driven servers – a move that severely threatens chip king Intel, and would be equivalent to a massive influx of steroids into the burgeoning ARM ecosystem.

Another smoking gun for Facebook's shift is a job posting on the company's site for an ARM server software engineer.

"Facebook is seeking an experienced Software Engineer to help us port the world’s best PHP run-time on servers based on ARM processor," the company wrote. "We aim to evaluate further improving the efficiency of our web tier by porting HipHopVM to new server hardware platforms based on power-efficient ARM."

The social networking giant has also contributed a server design to its Open Compute Project scheme named "Group Hug" that allows for swappable CPUs, enabling it to efficiently flip Intel for ARM.

This is a sign of accelerated research by the company into ARM server development, given that it told your humble hack in September 2012 that it was actively evaluating ARM and Tilera chips in its data centers.

At the time Facebook was asked if it was planning a broad shift to non-x86 chips for production workloads. "It's not a question of if; it's a question of when," said Facebook system engineer Amir Michael.

Though Facebook is keen to evaluate ARM chips in production, admittedly this shift will take a long time to play out.

"We definitely feel it's going to take at least two to three years before the ARM ecosystem as well as ARM mature to a point where we can actually deploy it [in production]," Facebook technology strategist and former AMD chap Vijay Rao said at the Linaro Connect Conference at the end of October.

We'll delve further into why both Facebook and Google are keen on ARM in an upcoming analysis piece, and discuss how and why they'll deploy their software on non-x86 chips.

At the time of writing, Facebook had not responded to a request for more information on the PHP translator work. ®