On Wed, 6 Jan 2021 01:27:09 GMT, Claes Redestad <[email protected]> wrote:
>> By caching default constructors used in >> `java.security.Provider::newInstanceUtil` in a `ClassValue`, we can reduce >> the overhead of allocating instances in a variety of places, e.g., >> `MessageDigest::getInstance`, without compromising thread-safety or security. >> >> On the provided microbenchmark `MessageDigest.getInstance(digesterName)` >> improves substantially for any `digesterName` - around -90ns/op and -120B/op: >> Benchmark >> (digesterName) Mode Cnt Score Error Units >> GetMessageDigest.getInstance >> md5 avgt 30 293.929 ± 11.294 ns/op >> GetMessageDigest.getInstance:·gc.alloc.rate.norm >> md5 avgt 30 424.028 ± 0.003 B/op >> GetMessageDigest.getInstance >> SHA-1 avgt 30 322.928 ± 16.503 ns/op >> GetMessageDigest.getInstance:·gc.alloc.rate.norm >> SHA-1 avgt 30 688.039 ± 0.003 B/op >> GetMessageDigest.getInstance >> SHA-256 avgt 30 338.140 ± 13.902 ns/op >> GetMessageDigest.getInstance:·gc.alloc.rate.norm >> SHA-256 avgt 30 640.037 ± 0.002 B/op >> GetMessageDigest.getInstanceWithProvider >> md5 avgt 30 312.066 ± 12.805 ns/op >> GetMessageDigest.getInstanceWithProvider:·gc.alloc.rate.norm >> md5 avgt 30 424.029 ± 0.003 B/op >> GetMessageDigest.getInstanceWithProvider >> SHA-1 avgt 30 345.777 ± 16.669 ns/op >> GetMessageDigest.getInstanceWithProvider:·gc.alloc.rate.norm >> SHA-1 avgt 30 688.040 ± 0.003 B/op >> GetMessageDigest.getInstanceWithProvider >> SHA-256 avgt 30 371.134 ± 18.485 ns/op >> GetMessageDigest.getInstanceWithProvider:·gc.alloc.rate.norm >> SHA-256 avgt 30 640.039 ± 0.004 B/op >> Patch: >> Benchmark >> (digesterName) Mode Cnt Score Error Units >> GetMessageDigest.getInstance >> md5 avgt 30 210.629 ± 6.598 ns/op >> GetMessageDigest.getInstance:·gc.alloc.rate.norm >> md5 avgt 30 304.021 ± 0.002 B/op >> GetMessageDigest.getInstance >> SHA-1 avgt 30 229.161 ± 8.158 ns/op >> GetMessageDigest.getInstance:·gc.alloc.rate.norm >> SHA-1 avgt 30 568.030 ± 0.002 B/op >> GetMessageDigest.getInstance >> SHA-256 avgt 30 260.013 ± 15.032 ns/op >> GetMessageDigest.getInstance:·gc.alloc.rate.norm >> SHA-256 avgt 30 520.030 ± 0.002 B/op >> GetMessageDigest.getInstanceWithProvider >> md5 avgt 30 231.928 ± 10.455 ns/op >> GetMessageDigest.getInstanceWithProvider:·gc.alloc.rate.norm >> md5 avgt 30 304.020 ± 0.002 B/op >> GetMessageDigest.getInstanceWithProvider >> SHA-1 avgt 30 247.178 ± 11.209 ns/op >> GetMessageDigest.getInstanceWithProvider:·gc.alloc.rate.norm >> SHA-1 avgt 30 568.029 ± 0.002 B/op >> GetMessageDigest.getInstanceWithProvider >> SHA-256 avgt 30 265.625 ± 10.465 ns/op >> GetMessageDigest.getInstanceWithProvider:·gc.alloc.rate.norm >> SHA-256 avgt 30 520.030 ± 0.003 B/op >> >> See: >> https://cl4es.github.io/2021/01/04/Investigating-MD5-Overheads.html#reflection-overheads >> for context. > > Claes Redestad has updated the pull request incrementally with one additional > commit since the last revision: > > Add cloneInstance baseline micro src/java.base/share/classes/java/security/MessageDigest.java line 185: > 183: MessageDigest md; > 184: > 185: GetInstance.Instance instance = > GetInstance.getInstance("MessageDigest", There is another Security.getImpl call inside getInstance(String algorithm, String provider) method. For consistency sake, we should update it also? src/java.base/share/classes/java/security/Provider.java line 1072: > 1070: } > 1071: public int hashCode() { > 1072: return type.hashCode() ^ algorithm.hashCode(); Is this change really necessary? It's faster to compute with ^, but does the generated hash values are as distinct as using Objects.hash()? src/java.base/share/classes/java/security/Provider.java line 1930: > 1928: Class<?> clazz = null; > 1929: if (cache instanceof WeakReference<?> ref){ > 1930: clazz = (ref == null) ? null : (Class<?>)ref.get(); ref should not be null if the instanceof check is true? src/java.base/share/classes/java/security/Provider.java line 1963: > 1961: Constructor<?> con = null; > 1962: if (cache instanceof WeakReference<?> ref){ > 1963: con = (ref == null) ? null : (Constructor<?>)ref.get(); ref should not be null if the instanceof check is true? src/java.base/share/classes/sun/security/jca/ProviderConfig.java line 170: > 168: } > 169: // DCL > 170: synchronized (ProviderConfig.class) { synchronized (this) instead since 'provider' is an instance field? ------------- PR: https://git.openjdk.java.net/jdk/pull/1933
