Miscellaneous jar improvements

[Andrew Haley]

Martin Buchholz wrote:
> On Thu, Sep 10, 2009 at 09:57, Andrew Haley<aph at redhat.com> wrote:
>> Martin Buchholz wrote:
>>> Regarding improving build times:
>>>
>>> The jar command that is actually used to build rt.jar is from the
>>> bootstrap jdk,
>>> so patching the jdk that you are about to build won't help directly.
>> Sure, but building JDK on any free software distro uses the immediately
>> previous JDK.  Therefore, all that means is that the improvement is
>> delayed by one release cycle.
>>
>>> However, there is another patch that will improve build times
>>> even when using an old boot jdk.
>>>
>>> changeset:   1283:ff32c270102a
>>> user:        martin
>>> date:        Mon Jun 22 21:07:20 2009 -0700
>>> summary:     6853806: Prefer (cd $dir && jar) to jar -C for performance reasons

Weird, I can't find that changeset.  Got a URL?

>>> All told, there were at least 3 separate changesets in openjdk7 to
>>> make building rt.jar faster.
>> But you put the lot into http://hg.openjdk.java.net/jdk6/jdk6/jdk/rev/b35f1e5075a4,
>> right?  That's what we have in IcedTea 6.
> 
> No, I was too lazy to backport 6853806.
> (Perhaps I determined it was unnecessary?  I don't recall)
> 
> The changes to the jar command benefit all users of the jar command,
> unlike 6853806, which only benefits us poor folks building openjdk.

Aha!  Proof, if any more were needed, that it would be better to have
had the backport discussion online... ;-)

Out of interest, why does changing "jar -C" to (cd $dir && jar) make
anything go faster?

Andrew.