RFR: 8234543: ZGC: Parallel pre-touch

[Per Liden]

Thanks Erik!

/Per

On 11/26/19 3:58 PM, erik.osterlund at oracle.com wrote:
> Hi Per,
> 
> Still good.
> 
> Thanks,
> /Erik
> 
> On 11/25/19 3:10 PM, Per Liden wrote:
>> I noticed that we didn't have a test for this on ZGC, so I added one:
>>
>> Updated webrev: http://cr.openjdk.java.net/~pliden/8234543/webrev.1
>>
>> /Per
>>
>> On 11/21/19 10:32 AM, Per Liden wrote:
>>> When using -XX:+AlwaysPreTouch, ZGC is currently doing single 
>>> threaded pre-touch. This patch makes this a parallel operation. This 
>>> improves startup time, especially when using large heaps. For 
>>> example, when using a 3TB heap (-XX:+AlwaysPreTouch -Xms3T -Xmx3T), 
>>> startup time is improved by about 30x.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8234543
>>> Webrev: http://cr.openjdk.java.net/~pliden/8234543/webrev.0
>>>
>>> /Per
>