Is anyone able to build on Win 7 (original) (raw)

Volker Simonis volker.simonis at gmail.com
Tue Feb 14 14:59:11 UTC 2012

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

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

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

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

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

"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

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

//Fredrik

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