On Mon, Mar 19, 2018 at 02:59:24PM +0000, Balint Reczey wrote: > Hi, > > Initramfs-tools uses gzip compression by default which served us well > for quite some time but LZ4 offers way faster decompression while > making a only slightly bigger initramfs files. > > On my old laptop the initramfs extraction time decreased from ~1.2s to ~0.24s: > (with lz4) > kernel: [ 0.297726] Unpacking initramfs... > kernel: [ 0.535061] Freeing initrd memory: 77940K > kernel: [ 0.301637] Unpacking initramfs... > kernel: [ 0.539109] Freeing initrd memory: 77940K > (with gzip) > kernel: [ 0.273748] Unpacking initramfs... > kernel: [ 1.490066] Freeing initrd memory: 57140K > kernel: [ 0.281729] Unpacking initramfs... > kernel: [ 1.498493] Freeing initrd memory: 57140K > > The increase in the initrd.img size is ~14%: > (lz4) > -rw-r--r-- 1 root root 66709065 márc 19 14:24 > /boot/initrd.img-4.15.0-12-generic > (gzip) > -rw-r--r-- 1 root root 58510993 márc 19 12:57 > /boot/initrd.img-4.15.0-12-generic.bak > > Initramfs creation speed also improved a bit from ~24s to ~21s wall clock > time: > (lz4) > update-initramfs: Generating /boot/initrd.img-4.15.0-12-generic > 14.97user 6.31system 0:20.47elapsed 103%CPU (0avgtext+0avgdata > 22368maxresident)k > update-initramfs: Generating /boot/initrd.img-4.15.0-12-generic > 15.18user 6.49system 0:20.48elapsed 105%CPU (0avgtext+0avgdata > 22308maxresident)k > (gzip) > update-initramfs: Generating /boot/initrd.img-4.15.0-12-generic > 18.23user 6.77system 0:23.61elapsed 105%CPU (0avgtext+0avgdata > 22396maxresident)k > update-initramfs: Generating /boot/initrd.img-4.15.0-12-generic > 18.38user 6.83system 0:23.82elapsed 105%CPU (0avgtext+0avgdata > 22292maxresident)k
For me it was 16 -> 10 I think. > > Base on the results I plan adding LZ4 compression support to > initramfs-tools as requested in LP: #1488620 [1] in the next days > without setting it as default > +1 > and I propose setting LZ4 as default for 18.10. We might have zstd support by that time (I hope), it might make sense to use that then (better space/time tradeoff), but we'll have to see. -- debian developer - deb.li/jak | jak-linux.org - free software dev ubuntu core developer i speak de, en -- ubuntu-devel mailing list ubuntu-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel
