ZRAM Will See Greater Performance On Linux 5.1 - It Changed Its Default Compressor

For those relying upon ZRAM to provide a compressed block device in RAM for cases like using it for SWAP or /tmp, with Linux 5.1 you might find it performing better than earlier kernels.

With Linux 5.1, the ZRAM block driver has changed its default compressor from "lzo" to "lzo-rle."

LZO-RLE? This LZO-RLE support came via Arm developers for enhancing the LZO compression support. LZO-RLE was added just last week to the Linux kernel at the start of the 5.1 merge window. LZO-RLE is short for "Run-length Encoding" and is designed to offer better performance over traditional LZO. Arm developers are also the one applying this default compressor change.

With the change to the ZRAM driver, the LZO-RLE mode is said to yield similar compression ratios to traditional LZO but with higher performance.

In a previous mailing list thread by Arm's Dave Rodgman, he found when opening 80 browser tabs to cause swapping on the system that there was a 27% reduction in total time spent compressing/decompressing data. Hopefully you don't suffer from heavy swapping in the first place, but if you do or you rely on ZRAM for /tmp or similar use-cases, with Linux 5.1 you will hopefully see better performance.