RFR(s): 8218145: block_if_requested is not proper inlined due to size

[Robbin Ehn]

Thanks, yes!

/Robbin

On 2019-02-01 17:34, Gerard Ziemski wrote:
> hi Robbin,
> 
> Looks good, but couldn’t we have:
> 
>    86 void SafepointMechanism::block_if_requested_slow(JavaThread *thread) {
>    87   if (global_poll()) {
>    88     SafepointSynchronize::block(thread);
>    89   }
>    90   if (uses_thread_local_poll() && thread->has_handshake()) {
>    91     // local poll already checked
>    92     thread->handshake_process_by_self();
>    93   } // else { If we don't have per thread poll this could a handshake or a safepoint }
>    94 }
> 
> instead of:
> 
>    86 void SafepointMechanism::block_if_requested_slow(JavaThread *thread) {
>    87   if (uses_thread_local_poll()) {
>    88     // local poll already checked
>    89     if (global_poll()) {
>    90       SafepointSynchronize::block(thread);
>    91     }
>    92     if (thread->has_handshake()) {
>    93       thread->handshake_process_by_self();
>    94     }
>    95   } else {
>    96     // If we don't have per thread poll this could a handshake or a safepoint
>    97     if (global_poll()) {
>    98       SafepointSynchronize::block(thread);
>    99     }
>   100   }
>   101 }
> 
> if we want to reduce the code size?
> 
> 
> cheers
> 
>> On Feb 1, 2019, at 3:54 AM, Robbin Ehn <robbin.ehn at oracle.com> wrote:
>>
>> Hi all, please review.
>>
>> Code:
>> http://cr.openjdk.java.net/~rehn/8218145/webrev/index.html
>> Issue:
>> https://bugs.openjdk.java.net/browse/JDK-8218145
>>
>> SafepointMechanism::block_if_requested(JavaThread*) is often not inlined to due inline-unit-growth.
>> This improve the inlining frequency with 6-7x.
>> Some startup benchmarks show 1% better time.
>>
>> Test -+ThreadsLocalHandshakes and t1.
>>
>> Note that we are planning to deprecate -ThreadsLocalHandshakes in 13, therefore -ThreadsLocalHandshakes is put in slow path to further reduce size.
>> When we can remove the uses_thread_local_poll() it become so small it is always inlined. Arguably this method should have ALWAYSINLINE, but I would prefer not.
>>
>> Thanks, Robbin
>