Meta develops Compressed RAM 'CRAM' for Linux

Meta engineer Gregory Price presented Compressed RAM (CRAM) at the Linux Plumbers Conference in Prague — hardware-offloaded memory compression with cacheline-level access. Reads run at near-native DRAM speeds, while writes are up to 5.4x faster than ZRAM in the worst tested case with 20% writes.

• CRAM uses a private NUMA node instead of emulating a block device
• Reads from compressed memory match raw DRAM performance
• Writes are up to 5.4x faster than ZRAM with 20% write load
• Most pieces needed for CRAM are already in mainline