On Mon, Jan 28, 2013 at 11:29:14PM -0500, Nicolas Pitre wrote: > On Mon, 28 Jan 2013, Andrew Morton wrote: > > > On Sat, 26 Jan 2013 14:50:43 +0900 > > Kyungsik Lee <kyungsik.lee@xxxxxxx> wrote: > > > > > This patchset is for supporting LZ4 compressed kernel and initial ramdisk on > > > the x86 and ARM architectures. > > > > > > According to http://code.google.com/p/lz4/, LZ4 is a very fast lossless > > > compression algorithm and also features an extremely fast decoder. > > > > > > Kernel Decompression APIs are based on implementation by Yann Collet > > > (http://code.google.com/p/lz4/source/checkout). > > > De/compression Tools are also provided from the site above. > > > > > > The initial test result on ARM(v7) based board shows that the size of kernel > > > with LZ4 compressed is 8% bigger than LZO compressed but the decompressing > > > speed is faster(especially under the enabled unaligned memory access). > > > > > > Test: 3.4 based kernel built with many modules > > > Uncompressed kernel size: 13MB > > > lzo: 6.3MB, 301ms > > > lz4: 6.8MB, 251ms(167ms, with enabled unaligned memory access) > > > > What's this "with enabled unaligned memory access" thing? You mean "if > > the arch supports CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS"? If so, > > that's only x86, which isn't really in the target market for this > > patch, yes? > > I'm guessing this is referring to commit 5010192d5a. > > > It's a lot of code for a 50ms boot-time improvement. Does anyone have > > any opinions on whether or not the benefits are worth the cost? > > Well, we used to have only one compressed format. Now we have nearly > half a dozen, with the same worthiness issue between themselves. > Either we keep it very simple, or we make it very flexible. The former > would argue in favor of removing some of the existing formats, the later > would let this new format in. This reminded me to check the status of the lzo update and it seems it got lost? http://lkml.org/lkml/2012/10/3/144 (Cc: added, I hope Markus still cares and someone could eventually take his patch once he resends it.) Johannes -- 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
