From mboxrd@z Thu Jan 1 00:00:00 1970 From: js@sig21.net (Johannes Stezenbach) Date: Wed, 15 Aug 2012 16:45:39 +0200 Subject: [GIT PULL] Update LZO compression In-Reply-To: <502B8FE3.7080501@oberhumer.com> References: <50299142.2030504@oberhumer.com> <20120814123937.GA14756@sig21.net> <502B8FE3.7080501@oberhumer.com> Message-ID: <20120815144539.GA8300@sig21.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Marcus, On Wed, Aug 15, 2012 at 02:02:43PM +0200, Markus F.X.J. Oberhumer wrote: > On 2012-08-14 14:39, Johannes Stezenbach wrote: > > On Tue, Aug 14, 2012 at 01:44:02AM +0200, Markus F.X.J. Oberhumer wrote: > >> On 2012-07-16 20:30, Markus F.X.J. Oberhumer wrote: > >>> > >>> As stated in the README this version is significantly faster (typically more > >>> than 2 times faster!) than the current version, has been thoroughly tested on > >>> x86_64/i386/powerpc platforms and is intended to get included into the > >>> official Linux 3.6 or 3.7 release. > >>> > >>> I encourage all compression users to test and benchmark this new version, > >>> and I also would ask some official LZO maintainer to convert the updated > >>> source files into a GIT commit and possibly push it to Linus or linux-next. > > > > Sorry for not reporting earlier, but I didn't have time to do real > > benchmarks, just a quick test on ARM926EJ-S using barebox, > > and found in the new version decompression is slower: > > http://lists.infradead.org/pipermail/barebox/2012-July/008268.html > > I can only guess, but maybe your ARM cpu does not have an efficient > implementation of {get,put}_unaligned(). Yes, ARMv5 cannot do unaligned access. ARMv6+ could, but I think the Linux kernel normally traps it for debug, all ARM seem to use generic {get,put}_unaligned() implementation which use byte access and shift. > Could you please try the following patch and test if you can see > any significant speed difference? It isn't. I made the attached quick hack userspace code using ARM kernel headers and barebox unlzop code. (new == your new code, old == linux-3.5 git, test == new + your suggested change) (sorry I had no time to clean it up) I compressed a Linux Image with lzop (lzop lzoimage) and timed uncompression: # time ./unlzopold /dev/null real 0m 0.29s user 0m 0.19s sys 0m 0.10s # time ./unlzopold /dev/null real 0m 0.29s user 0m 0.20s sys 0m 0.09s # time ./unlzopnew /dev/null real 0m 0.41s user 0m 0.30s sys 0m 0.10s # time ./unlzopnew /dev/null real 0m 0.40s user 0m 0.30s sys 0m 0.10s # time ./unlzopnew /dev/null real 0m 0.40s user 0m 0.29s sys 0m 0.11s # time ./unlzoptest /dev/null real 0m 0.39s user 0m 0.28s sys 0m 0.11s # time ./unlzoptest /dev/null real 0m 0.39s user 0m 0.27s sys 0m 0.11s # time ./unlzoptest /dev/null real 0m 0.39s user 0m 0.27s sys 0m 0.11s FWIW I also checked the sha1sum to confirm the Image uncompressed OK. Johannes -------------- next part -------------- A non-text attachment was scrubbed... Name: lzo-bench.tar.gz Type: application/octet-stream Size: 54224 bytes Desc: not available URL: