Re: RFR: 8246241: LambdaFormEditor should use a transform lookup key that is not a SoftReference

[Claes Redestad]

On 2020-06-01 20:48, Paul Sandoz wrote:

Looks good. I sent some trivial comments offline.

Thanks!

Adjusted the webrev in-place based on your comments (A few methods were
public that should be private, etc..)

/Claes

Paul.

On Jun 1, 2020, at 4:07 AM, Claes Redestad <claes.redes...@oracle.com> wrote:

Hi,

the LambdaFormEditor uses a SoftReference-based cache to avoid
generating LambdaForms we have already generated. By introducing a
lookup key that is not a SoftReference we can improve this by allocating
less up front and by inducing less work for the GC later on.

I also refactored a few cases where I had neglected to add a static
factory method to create the Transform (now TransformKey). For the
transform types affected this helps further reduce allocations.

Bug:    https://bugs.openjdk.java.net/browse/JDK-8246241
Webrev: http://cr.openjdk.java.net/~redestad/8246241/open.00/

Testing: tier1-2, java/lang/invoke locally with STRESS_TEST=true

Verified a speed-up on the micro added by JDK-8246152)[1], and
on related startup tests[2].

Thanks!

/Claes

[1]
Before (JDK-8246152):
Benchmark Mode Cnt Score Error Units
StringConcatFactoryBootstraps.makeConcatWithConstants avgt 10 2764.634 ± 56.244 
ns/op
StringConcatFactoryBootstraps.makeConcatWithConstants:·gc.alloc.rate.norm avgt 
10 4136.187 ± 0.013 B/op

After:
Benchmark                Mode  Cnt     Score     Error   Units
StringConcatFactoryBootstraps.makeConcatWithConstants avgt 10 2299.919 ± 58.003 
ns/op
StringConcatFactoryBootstraps.makeConcatWithConstants:·gc.alloc.rate.norm avgt 
10 3308.145 ± 6.378 B/op

[2] 
http://cr.openjdk.java.net/~redestad/scratch/erase_scf_types.00/ObjStringCombos.java

Before (JDK-8246152):
     3,485,679,714      instructions              #    1.09  insn per cycle     
      ( +-  0.90% )
       692,247,529      branches                  #  491.822 M/sec          ( 
+-  0.92% )
        28,939,534      branch-misses             #    4.18% of all branches    
      ( +-  0.90% )

       0.291642667 seconds time elapsed          ( +-  0.93% )

After:
     3,411,619,586      instructions              #    1.09  insn per cycle     
      ( +-  0.63% )
       677,767,258      branches                  #  493.911 M/sec              
 ( +-  0.64% )
        28,337,022      branch-misses             #    4.18% of all branches    
      ( +-  0.63% )

       0.288959534 seconds time elapsed          ( +-  0.86% )