Is anyone able to build on Win 7

[Volker Simonis]

On Tue, Feb 14, 2012 at 12:43 PM, Fredrik Öhrström
<fredrik.ohrstrom at oracle.com> wrote:
> 2012-02-14 12:29, Volker Simonis skrev:
>> To cut a long story short:
>> - disabling "on access" scanning of *.{java,c,cpp,h,hpp} seems to
>> resolve the file io problems (permission denied, access denied)
>> - disabling ASLR seems to resolve the "fork" problems
>
> Great work! Do you know if disabling ASLR affects the fork performance
> on 64 bit windows?
>

No, definitely not.
The build time on my DualCore i7 @ 2.7 GHz notebook with 8GB Ram is
constantly 1h43min for a full JDK8 opt build.

Now that that the build seems stable I want to compare it with a Linux
build in a VirtualBox VM on the same host.
I'll let you know the results once I'm done, but I don't think that
"fork" is the big problem - at least not the only one.

But once you asked here's my main suspect since long time (you asked
so you have to read the conspiracy:)

stat (or lstat/fstat/stat64 ...)
---------------------------------

I'm quite sure that the poor implementation of stat in Cygwin and its
usage in make is one of the main reasons
why the build Windows build is so terrible slow in Windows compared to Linux.

I first realized this years ago when I was first building Windows
inside a VMWare image with the sources on
network shares. The build times were excessively long and it was not
the compile times because SMB shares
do a quite efficient caching - it was the times which make needed in
order to check the build dependencies.
The build times could be improved by factors if the sources were moved
to a local disc.

But even locallly, I think that the stat calls for large dependency
lists as we have them in the OpenJDK build
may still be one of the causes for the slow build. Running make inside
strace will reveal the shear number
of these calls and there is evidence that the stat performance is
really poor in Cygwin.

I'll attach some unsorted links to some of the resources which discuss
this issue just in case somebody wants to
deep dive into this topic. I'm definitely not a Windows/Cygwin expert
and I can't promise I'll have the time
to solve it 'real soon' but I'll definitely stick to this topic
because it is a real PITA (especially if you want to
change your build from MKS to Cygwin the developers who will first
love you because freed them from of
the MKS licensing night mare will very soon kill you because of the
build times:)

"performance issue with cgywin make"
http://www.mail-archive.com/make-w32@gnu.org/msg01353.html

- mailing list thread which compares the bad performance of Cygwin
make with MS nmake and discusses
how some of the problems have been solved in CMake by using direct
windows sys-calls instead of stat.

"make 3.82 performing more stat() calls than 3.81"
http://lists.gnu.org/archive/html/bug-make/2011-09/msg00025.html

- mailing list thread discussing a bug in make 3.82 which leads to
even more calls to stat
(and has been fixed already in the head revision of make)


"Cygwin Performance and stat()"
http://omgili.com/mailinglist/cygwin/cygwin/com/efe8a37b2e4466daa7b6eb1aa610c3d7squirrelwwwwebmailwingertorg.html

- very long thrad, very ‘flamy’, no outcome, some interesting infos nevertheless

"cygwin: Use native Win32 API for stat"
http://marc.info/?l=git&m=122278284210941

- partial patch for the problem by implementing a stripped down
version of stat which does just enough...

"_NutFastStat(), _NutFastStat64()"
http://www.mkssoftware.com/docs/man3/_NutFastStat.3.asp

- MKSs limited but faster version of stat (not sure if MKS make uses
this, but that may be an
explanation why builds under MKS are reported to be considerably
faster compared to Cygwin builds

"Managing Projects with GNU Make, 3rd Edition, The Power of GNU make
for Building Anything, By Robert Mecklenburg"
http://shop.oreilly.com/product/9780596006105.do

- Chapter 10: "Improving the Performance of make" freely available as
PDF download:
http://reilly.com/catalog/make3/book/ch10.pdf


"Compile time Local Cygwin vs. VMware session on same system"
http://cygwin.com/ml/cygwin/2008-10/threads.html#00415

- mail thread suggesting the usage of ‘dash’ instead of ‘bash’ for a
>10% performance improvement

> //Fredrik
>