Re: [RFC PATCH v2 0/4] Add support for LZ4-compressed kernel

Russell King - ARM Linux
2013-02-27T16:33:56Z

On Wed, Feb 27, 2013 at 07:49:12AM -0800, Joe Perches wrote:
> On Wed, 2013-02-27 at 09:56 +0000, Russell King - ARM Linux wrote:
> > On Tue, Feb 26, 2013 at 05:40:34PM -0800, Joe Perches wrote:
> > > On Tue, 2013-02-26 at 22:10 +0000, Russell King - ARM Linux wrote:
> > > > So... for a selected kernel version of a particular size, can we please
> > > > have a comparison between the new LZO code and this LZ4 code, so that
> > > > we can see whether it's worth updating the LZO code or replacing the
> > > > LZO code with LZ4?
> > >
> > > How could it be questionable that it's worth updating the LZO code?
> >
> > Please read the comments against the previous posting of these patches
> > where I first stated this argument - and with agreement from those
> > following the thread. The thread started on 26 Jan 2013. Thanks.
>
> https://lkml.org/lkml/2013/1/29/145
>
> I did not and do not see significant value in
> adding LZ4 given Markus' LZO improvements.

Sorry, a 66% increase in decompression speed over the updated LZO code
isn't "significant value" ?

I'm curious - what in your mind qualifies "significant value" ?

Maybe "significant value" is a patch which buggily involves converting
all those "<n>" printk format strings in assembly files to KERN_* macros,
thereby breaking those strings because you've not paid attention to what
.asciz means? (Yes, I've just cleaned that crap up after you...)

> Why would the LZO code not be updated?

I'm not saying that the LZO code should not be updated. I'm saying that
the kernel boot time decompressor is not a play ground for an ever
increasing number of "my favourite compression method" crap. We don't
need four, five or even six compression methods there. We just need
three - a "fast but large", "small but slow" and "all round popular
medium".