Re: [classlib] [archive] Re: jar and zip optimizations

Tue, 08 Apr 2008 03:18:57 -0700 

Hello, Alexei!

I finally figured out, whats going on there. There are 2 zlib's.
The first one is downloaded as a zlib1.dll and zdll.lib and used in vm. zdll.lib is not a static version of zlib, as I thought, but rather it is the import library for zlib1.dll, which means that if we include this lib in a linkage - we get implicit dependency (at a compile/link time) on the .dll and all it's functions exported to the code. And that's how it works. I still don't know why vm is dynamically connects to hyzlib.dll and never exports any functions from it, maybe it makes sense under Linux, but under Windows it's redundant. 


Another zlib is called hyzlib.dll and it's downloaded in source codes 
and built in classlib. It is dynamically loaded by hyarchive.dll. It 
also builds its import library hyzlib.lib.
"working_classlib\modules\archive\src\main\native\zip\shared\zipsup.c" 
explicitly exports 3 functions in the code under different names 
(inflateInit2Func, inflateFunc, inflateEndFunc). That's unnecessary, 
because hyzlib.lib is included in linkage and we have all hyzlib's 
functions in the code. As an evidence 
"working_classlib\modules\archive\src\main\native\archive\shared\inflater.c" 
uses inflate functions as is, without exporting. Again, maybe it makes 
sense under Linux.



So what I'm doing now is trying to replace zlib1.dll and zdll.lib with 
my optimized ones. But I have some difficulties with building dll. First 
of all MSVC 9.0 is a default compiler/linker on my machine. So when I 
link a dll I get a dependency on msvcr90.dll. Well, ok, I can place it 
next to my dll for now. Furthermore I get a runtime error R6034 when 
trying to connect my dll with anything else. It has something to do with 
manifest, but I couldn't find anything like it in a zlib's standard 
makefiles or hyzlib's makefiles. Maybe switching to another compiler 
will be the best option.


Alexei Fedotov wrote:

Dmitry,
What happens if you delete (add <delete file="<path to zlib1.dll>" />
to working_vm/build.xml at setup target)
this library right before the compilation starts?

Thanks.


On Mon, Apr 7, 2008 at 8:25 PM, Dmitry Egorov <[EMAIL PROTECTED]> wrote:

  

Hello, Mark.




    

I'm curious to know whether you plan to make zlib optimisations that are
harmony specific.  If not, then it would be much better to contribute
them back to the zlib project directly and not maintain them in the
harmony project.


      

 No, this optimizations are not Harmony specific, but  uses external
optimization library, which is not free. I already have optimized zlib, so I
just need to build it into Harmony.

 My current goal is to make a small step - integrate my zlib into vm build
system on my computer and see if I get considerable Harmony's performance
increase. Based on results I can therefore think of integrating it in a
"good way", which means searching for the optimization library's presence on
the system and loading alternative zlib in case it is found.

 For that goal I just need to be sure that vm is using zlib1.dll, downloaded
from the internet. Dependency walker says it is, but what confuses me is
zdll.lib. Is it just redundunt or used somewhere?



 Mark Hindess wrote:


    

HY_LOCAL_ZLIB is set by the ant option -Dhy.local.zlib=true.  It is
intended for use on unix machines where libz.so is typically already
available (and in memory).  This option is not enabled by default but
since the zlib api is pretty stable this would seem to be a reasonable
default for unix machines.  I do set this option when building the
debian packages (which is why I noticed/reported that the harmony
version was not using the most effective compiler optimisations on linux
x86/x86_64).

I'm curious to know whether you plan to make zlib optimisations that are
harmony specific.  If not, then it would be much better to contribute
them back to the zlib project directly and not maintain them in the
harmony project.

-Mark.


On 5 April 2008 at 16:41, Dmitry Egorov <[EMAIL PROTECTED]> wrote:



      

Hello, everyone!
I'm now working on zlib optimization using external performance library.

        

For now my goal is to make Harmony use my modified zlib code instead of the
one downloaded from the internet.

    

So I've been struggling with build system for quite a long time. As far

        

as I can understand now, both vm and classlib use hyzlib.dll (i'm currently
working in Windows), which is made by downloading and compiling zlib's
sources in classlib's buildfiles.

    

But I'm not sure, because there's code in vm's build files which

        

downloads zlib1.dll and zdll.lib. But I can't figure out whether vm is using
it or not. On the other side, I found that vm has code related to

    

hyzlib.dll in working_vm\vm\vmcore\src\init\vm_properties.cpp:
static const char *api_dll_files[] =
{
   "harmonyvm",
   "hythr",
#if !defined(HY_NO_SIG)
   "hysig",
#endif
   "hyprt",
#if defined(HY_LOCAL_ZLIB)
   "z",
#else
   "hyzlib",
#endif
   "hynio",
   "vmi",
   "hyluni",
   "hyarchive"
}; ...

My primary goal is to optimize vm's zlib performance to boost start up

        

time. So my question is whether vm is using hyzlib.dll or not?

    

Tim Ellison wrote:



        

Dmitry Egorov wrote:



          

Hello Mark, Tim,
Thank you for your idea!  We have discussed possible native
optimizations of jar and zip code with Alexei Fedotov and I'm
currently looking into this.



            

Great.  Looking through the JIRAs I see Alexei raised a 'double read'

          

issue.  You still have outstanding questions about this Alexei?

    

[1] http://issues.apache.org/jira/browse/HARMONY-5526

Regards,
Tim





          





      

    





  
























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