Hey there,

double checked decompression performance on aging outdated silicon for you:

root@oqo:/usr/src/t2-trunk/download/mirror/l# time zstd -d < linux-4.7.tar.zst 
> /dev/null

real    0m33.215s
user    0m32.264s
sys     0m0.836s
root@oqo:/usr/src/t2-trunk/download/mirror/l# time bzip2 -d < linux-4.7.tar.bz2 
> /dev/null

real    2m25.235s
user    2m23.204s
sys     0m1.692s

this is on a really slooooow 999MHz Transmeta Crusoe:
http://t2-project.org/hardware/portable/OQO/01+/

vendor_id       : GenuineTMx86
cpu family      : 5
model           : 4
model name      : Transmeta(tm) Crusoe(tm) Processor TM5800
stepping        : 3
cpu MHz         : 999.015
cache size      : 512 KB
fdiv_bug        : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr cx8 sep cmov mmx longrun lrti 
constant_tsc eagerfpu
bugs            :
bogomips        : 1998.03
clflush size    : 32
cache_alignment : 32

On Oct 8, 2016, at 11:06, René Rebe <[email protected]> wrote:

> Hi,
> 
> On Oct 8, 2016, at 4:09, scsijon <[email protected]> wrote:
> 
>> On 10/05/2016 08:39 PM, René Rebe wrote:
>>> Hey,
>>> 
>>> On Oct 5, 2016, at 7:56, René Rebe <[email protected]> wrote:
>>> 
>>>> Hi,
>>>> 
>>>> On Oct 5, 2016, at 0:58, scsijon <[email protected]> wrote:
>>>> 
>>>>> On 10/05/2016 08:51 AM, René Rebe wrote:
>>>>>> Hey there,
>>>>>> 
>>>>>> I recently was made aware of Zstandard compression, and like some of 
>>>>>> it’s properties.
>>>>>> For example blazing fast decompression speed. This always annoyed me the 
>>>>>> most with the bzip2 that we like for two decades or so.
>>>>>> But this should also save storage and download traffic.
>>>>>> 
>>>>>> We prepared trunk so far, and we are re-compressing the trunk mirror 
>>>>>> archive.
>>>>>> 
>>>>>> I estimate some fallout, such as the host build system need to have zstd 
>>>>>> and it’s file need to know the zstd magic (patch in T2).
>>>>>> 
>>>>>> I will also test switching the “iso” binaries packages to zstd by 
>>>>>> default for smaller iso image and blazingly fast unpacking (e.g. to 
>>>>>> solid state storage, …).
>>>>>> 
>>>>>> Cheers,
>>>>>>  René
>>>>>> 
>>>>> 
>>>>> Hopefully if your going to do that, you will still allow settings to be 
>>>>> made for the current tar.bz2 input source files and output compiled 
>>>>> packages to stay as is as well as your new z compression. I really don't 
>>>>> want to have to download all of the mirror source packages I use again to 
>>>>> start with just because of a compression change.
>>>> 
>>>> Well one archive files in 18 years or so, … - scripts are complex enough - 
>>>> rather do not over engineer them more and keep it small and simple.
>>>> You can once run something like:
>>>> 
>>>> find download -name "*bz2" | while read f; do echo "$f" ${f%.bz2}.zst ; [ 
>>>> -f "${f%.bz2}.zst" ] || bunzip2 < $f | zstd -19 > ${f%.bz2}.zst ; done
>>>> 
>>>>> However, I do like the idea of having the compiled packages in a 
>>>>> different format to the source tree packages as well as a smaller iso to 
>>>>> deal with, i'd rather do that so I instantaneously know what has been 
>>>>> built.
>>>> 
>>>> Actually we already supported other binary output compressors, like .gz, 
>>>> .lzo, .xz, and .lzma or so.
>>>> 
>>>>> Can you please give us a link to which of the z compressions you intend 
>>>>> to use (I think there are 3 at present being touted to become the 
>>>>> 'standard'). Also are you also going to change the kernel setting to 
>>>>> match so compiled commands can be left compressed until used? That would 
>>>>> shrink things a bit although the processir will have to do a little bit 
>>>>> more work.
>>>> 
>>>> Not sure what you mean - I will do nothing to the kernel though.
>>>> 
>>>> Actually zstandard is much faster than all most other decompression - 
>>>> especially bzip2 (it is like as fast as just computing the fiel md5!) ;-)
>>>> 
>>>>    https://blog.fefe.de/?ts=a90c6783
>>>>    http://zstd.net
>>> 
>> 
>> well this is a new one to me and from a quick read doesn't seem to be kernel 
>> linked though so that makes four z standards. I wonder which will win.
> 
> Why does someone need to win? We choose whatever suits us best today, 150 
> other compression standards are fine too. Maybe one day another becomes 
> better than that, ...
> 
>> My understanding of the kernel setting, is that it will allow the commands, 
>> etc. over a certain size (anything non text format and the like) to remain 
>> in a compressed format until needed and only uncompressed when in ram. i'm 
>> not sure if this one is still alpha test mode or up to beta testing in the 
>> kernel end yet as I haven't both checked what's happening for a while on the 
>> kernel boards for a few months or attempted to compile a kernel since early 
>> 4.x.
> 
> This has nothing todo with kernel settings - this is about our binar package 
> tar.bz2 on the iso.
> 
> If I wanted a compressed files system I’d use btrfs with compress=whateever.
> 
>>> How much better actually is it? t2/trunk x86-i486:
>>> 
>>> -rw-r--r-- 1 root root 48064172 Oct  5 09:37 gcc-5.3.0.tar.zst.ultra
>>> -rw-r--r-- 1 root root 65978259 Oct  5 09:08 gcc-5.3.0.tar.zst.19
>>> -rw-r--r-- 1 root root 82942235 Oct  5 09:33 gcc-5.3.0.tar.bz2
>>> 
>>> Actually I thought to use level -19 for T2 packagers, but seeing --ultra 
>>> -22 maybe we should use that (though it takes a while to compress, … ;-)
>>> 
>> 
>> Also, if you use the ultra compression I do wonder if people will be turned 
>> off with a new download set time to repackage before download command 
>> compleats. Maybe you need to do a comparison test for a fresh download and 
>> with the two sets available ask if the second longer time is ok considering 
>> the space available. However on the other side of it with 'drive' space 
>> becoming cheaper and 'drives' becoming seriously larger, i'm not sure that 
>> is something to be considered in the equation any more.
> 
> I can not really follow this text - what do you mean to say / ask?
> 
> Normal users are only positively affected by this, the .zstd files are 
> smaller than the .bz2 we used, and de-compress way faster.
> It is a win-win all over - the only thing that takes longer is compression - 
> which usually only developers do. Using our mirrors the downloads already 
> come down as .zstd, ...
> And even than you can use the parallel pzstd flavor on a multi-core machine 
> to dramatically decrease the wall-clock-time.
> 
>       René
> 
> -- 
> ExactCODE GmbH, Lietzenburger Str. 42, DE-10789 Berlin
> http://exactcode.com | http://exactscan.com | http://ocrkit.com | 
> http://t2-project.org | http://rene.rebe.de
> 
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-- 
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 http://exactcode.com | http://exactscan.com | http://ocrkit.com | 
http://t2-project.org | http://rene.rebe.de

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