Re: [RFC PATCH 0/4] Add support for LZ4-compressed kernels
On 2013-01-29 오전 7:25, Andrew Morton wrote:
On Sat, 26 Jan 2013 14:50:43 +0900Yes, exactly. If the arch supports CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
then it is expected more boot-time improvement by LZ4-decompressor.
Currently there are two architectures which support it in mainline; x86 and powerpc.
And it is expected that ARM arch(v6 or above) also support it since the commit below.
Commit ID: 5010192d5
ARM: 7583/1: decompressor: Enable unaligned memory access for v6 and above
by Dave Martin
The test results(167ms) come from the ARM(v7 arch), MSM8960 based board with
Not only for the kernel but also the ramdisk can be compressed with LZ4 so
the boot-time would be more improved. The test case above didn't include
the decompressing time result for LZ4-compressed ramdisk.
So far the implementation is applicable to boot-time improvement for
LZ4-compressed kernel and ramdisk images but the decompressor module is
exported as an interface for other usages like LZO.
With LZ4 compressor(not yet implemented for the kernel), it is expected
that it will be used in many places in kernel such as crypto and fs(squashfs, btrfs).