Zstd'ing The Kernel Might See Mainline With Linux 5.9 For Faster Boot Times

It looks like the long ongoing work for compressing the Linux kernel image with Zstd might finally soon be mainlined, potentially for next month's Linux 5.9 cycle kicking off as the "v6" patches sent out this week were done as a Git pull request.

Nick Terrell of Facebook has been the one herding these Zstd patches for the Linux kernel and trying to get them upstream. Facebook is already using them in production on their many web servers.

Facebook found that using a Zstd compressed kernel image shrunk their x86_64 decompression time from 12 seconds to 3 seconds with formerly using XZ compression. The actual boot time dropped by about two seconds using Zstd over XZ. When testing the Zstd-compressed kernel on their AArch64 servers, Facebook found the decompression time shrunk from 27 seconds to 8 seconds.

As for the compression ratio, the Zstd compressed Linux kernel was smaller than a Gzip'ed kernel but larger than XZ or LZMA. The decompression time with Zstd was faster than anything except for LZ4.

Hopefully these patches will indeed get pulled for the upcoming Linux 5.9 kernel.