On Wed, Feb 27, 2013 at 09:04:48AM -0800, Joe Perches wrote: > On Wed, 2013-02-27 at 16:31 +0000, Russell King - ARM Linux wrote: > > 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" ? > > We disagree. ROTFL. > > I'm curious - what in your mind qualifies "significant value" ? > > faster boot time. smaller, faster overall code. ROTFL again! Because you've just disagreed with your above statement. "66% increase in decompression speed" as far as I know _is_ "faster boot time" ! > > 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...) > > If you mean commit 0cc41e4a21d43, perhaps you could clarify with an > example. I don't see any relevant changes by you in -next, but > maybe I'm not looking in the right spot. While recently asking someone to enable VFP debugging, so I could help sort out a problem they had reported, this is the debug output I was greeted by thanks to your meddling: [ 927.235546] \x01\x01\x01\x01\x01\x01\x01\x01 ... [ 927.241505] \x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01 Yes, really useful debug output isn't it? You can really see what's going on there. These are coming from ultimately two commits - the one you refer to above, which on its own would've changed the printk string to be merely "<7>" - and the follow on commit changing the way printk levels are dealt with. The above output is produced by: #define KERN_SOH "\001" /* ASCII Start Of Header */ #define KERN_DEBUG KERN_SOH "7" /* debug-level messages */ .asciz KERN_DEBUG "VFP: \str\n" 7.6 `.asciz "STRING"'... ======================== `.asciz' is just like `.ascii', but each string is followed by a zero ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ byte. The "z" in `.asciz' stands for "zero". ^^^^^ 0000 01003700 5646503a 20696e73 74722025 ..7.VFP: instr % ^^ ^^ 0010 30387820 70632025 30387820 73746174 08x pc %08x stat 0020 65202570 0a000100 37005646 503a2066 e %p....7.VFP: f ^^ ... That is: \x01 \x00 7 \x00 VFP: instr %08x pc %08x state %p \x00 See - three separately terminated strings because you changed: .asciz "<7>VFP: \str\n" to: .asciz "<7>" "VFP: \str\n" which turned it into _two_ separately NUL-terminated strings, and then the follow-on changes to printk kern levels changed this to: .asciz "\001" "7" "VFP: \str\n" producing _three_ separately NUL-terminated strings. The commit is not in mainline, nor linux-next, but in my tree as of yesterday (e36815e2e), ready to be pushed out when I've finished working on fixing other problems with VFP - or when I decide to push it out ready for submission during this merge window. > The change did enable reducing code size. ??? Yea, right, meanwhile breaking the ability of stuff to produce kernel messages. > > > Why would the LZO code not be updated? > > I'm not saying that the LZO code should not be updated. > > You said: > > > > > > > so that we can see whether it's worth updating the LZO code > > Sounded as if you were doubtful to me. _In_ the decompressor. We're talking about the _decompressor_ in this thread. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
