RFR: JDK-8140312: Enable new sjavac server only mode in jdk build

[Tim Bell]

Hi Erik:

Looks good to me.

/Tim

> I send this review prematurely. Here is a new webrev, which has been 
> properly tested. We had some test code compilations using the boot 
> javac, which hadn't properly declared DISABLE_SJAVAC. The copy paste 
> error in configure has also been corrected.
>
> On my workstation, running "make java" with hotspot already built, the 
> speedup goes from 2:32 to 1:35. Running just "make" with the default 
> target goes from about 4:05 to 3:10.
>
> Webrev: http://cr.openjdk.java.net/~erikj/8140312/webrev.02/
>
> /Erik
>
> On 2015-10-23 17:21, Magnus Ihse Bursie wrote:
>> On 2015-10-22 12:38, Erik Joelsson wrote:
>>> In JDK-8135131, sjavac added a thin server mode, in which only the 
>>> server part of sjavac is used for running plain javac. This patch 
>>> adds a configure option to enable this mode of running to the jdk 
>>> build. Later, if it seems to work well, we will consider making it 
>>> default.
>>>
>>> On my workstation (linux) running the default make target went from 
>>> about 4m55s to 4m05s when activating this.
>>
>> Did that test really use the new sjavac server? :-) The code looks 
>> broken, in common/autoconf/build-performance.m4 you set ENABLE_SJAVAC 
>> and not ENABLE_JAVAC_SERVER in the new flag.
>>
>> Apart from that, it looks good. :)
>>
>> /Magnus
>