Re: [PATCH] x86/boot: Support uncompressed kernel

[Sergey Senozhatsky <sergey.senozhatsky@gmail.com>]

On (03/23/17 08:07), Yinghai Lu wrote:
> On Thu, Mar 23, 2017 at 5:51 AM, Chao Peng <chao.p.peng@linux.intel.com> wrote:
> > Compressed kernel has its own drawback: uncompressing takes time. Even
> > though the time is short enough to ignore for most cases but for cases that
> > time is critical this is still a big number. In our on-going optimization
> > for kernel boot time, the measured overall kernel boot time is ~90ms while
> > the uncompressing takes ~50ms with gzip.
> >
> > The patch adds a 'CONFIG_KERNEL_RAW' configure choice so the built binary
> > can have no uncompressing at all. The experiment shows:
> >
> >     kernel               kernel size    time in decompress_kernel
> >     compressed (gzip)    3.3M           53ms
> >     uncompressed         14M            3ms
> 
> How about the time difference for bootloader to read kernel from
> flash/disk/network to ram?

there are also faster de-compressors than gzip out there. LZ4, for instance.
LZ4, as far as I remember, can be quite fast, like ~10 times faster than gzip.
have you tested it?

	-ss