MGLRU Linux Performance Looking Very Good For OpenWrt Router Use

For those running the embedded OpenWrt Linux operating system for routers and other networking devices or just running a memory-constrained MIPS Linux system, the forthcoming Multi-Gen LRU "MGLRU" kernel feature is looking very good on that front.

MGLRU is expected to land in Linux 6.1 for this big improvement over the current Linux kernel page reclamation code. Google engineers found the current page reclamation code to be too expensive and making poor eviction choices. MGLRU has been in development for a while as a big improvement especially when running under Linux memory pressure and this patch series has proved to provide noticeable benefits across many different workloads. Google is even using MGLRU in production already with Android and Chrome OS.

MGLRU benchmarks have been looking very good on a variety of hardware platforms and many different workloads. The latest extra weight to boast its advantages is MGLRU looking very good for MIPS embedded hardware with limited RAM capacity and/or OpenWrt for networking/router distributions.

Yu Zhao of Google and the lead MGLRU developer shared some benchmarks today looking at the MGLRU impact on OpenWrt / MIPS. Given the popularity of OpenWrt for running on WiFi routers, Yu Zhao ran some Memtier benchmarks with Memcached on an Ubiquiti EdgeRouter with/without MGLRU.

See all the details in full via this mailing list post but long story short, the MGLRU numbers are looking very good especially when the RAM is being over utilized. Hopefully Multi-Gen LRU remains on track for mainlining with Linux 6.1.