[10] RFR: 8179040: Avoid Ticks::now calls when EventClassLoad is not enabled

[David Holmes]

On 25/08/2017 1:38 AM, Claes Redestad wrote:
> Thanks Ioi and David for reviewing,
> 
> sadly there was some issues with building the previous patch without the 
> closed
> sources which has been corrected here:
> 
> http://cr.openjdk.java.net/~redestad/8179040/hotspot.03/

Incremental webrev possible?

Thanks,
David

> Thanks!
> 
> /Claes
> 
> On 2017-08-23 20:11, Ioi Lam wrote:
>> Hi Claes,
>>
>> The changes look good. Reviewed.
>>
>> Thanks
>>
>> - Ioi
>>
>>
>> On 8/23/17 5:32 AM, Claes Redestad wrote:
>>> Hi,
>>>
>>> this patch was never pushed due to an unfortunate interaction around 
>>> cancelling
>>> of events. Markus Grönlund has helped resolve these, while 
>>> maintaining the
>>> speedup:
>>>
>>> http://cr.openjdk.java.net/~redestad/8179040/hotspot.02/
>>>
>>> Thanks!
>>>
>>> /Claes
>>>
>>> On 04/25/2017 03:21 PM, Claes Redestad wrote:
>>>> Hi,
>>>>
>>>> this patch removes calling Ticks::now when EventClassLoad isn't 
>>>> enabled, which
>>>> has an effect on class loading performance:
>>>>
>>>> http://cr.openjdk.java.net/~redestad/8179040/hotspot.01/
>>>>
>>>> When tracing isn't enabled trace/tracing.hpp has dummy 
>>>> implementations which
>>>> are easily optimized away by a compiler, which I've verified happens 
>>>> on linux
>>>> OpenJDK builds with tracing disabled.
>>>>
>>>> On builds with tracing enabled then the changes means the call to 
>>>> get the time
>>>> only happen if the event is enabled, which achieves the sought after 
>>>> startup
>>>> optimization.
>>>>
>>>> Thanks!
>>>>
>>>> /Claes
>>>
>>
>