fastdebug vs jvmg

[Jesper Wilhelmsson]

Hi,

Last week I pulled build-infra/jdk8 from openjdk and I have a few questions 
and comments.

First I did as I have done before:
cd common/makefiles
sh ../autoconf/configure

And got: "This script needs bash to run.
It is recommended to use the configure script in the source tree root instead."

Configure from the root directory, nice! :-)

When configured I tried "make images" but the target was not recognized when I 
tried to build in the root directory. I went back to common/makefiles and ran 
'make images' there which worked as expected.

*Question:* Is it just the target 'images' that won't work in the root or are 
we still supposed to build from the common/makefiles directory? Building from 
the root would be really nice.


Then I reconfigured with --enable-debug.

--enable-debug currently configures hotspot to build with the build target 
fastdebug. fastdebug isn't really fast since asserts are turned on, and it 
can't be used for debugging since the code is optimized, so the name is a bit 
misleading. Personally I always use jvmg when debugging and testing.

I asked around the Stockholm office and it seems as most people here would 
prefer jvmg. It seems as jvmg is very slow on Mac so those who work on Mac 
only uses jvmg when debugging for real, not for regular testing, but otherwise 
fastdebug is rarely used here.

Cheers,
/Jesper