On Wed, 14 Jul 2021 17:06:02 GMT, Clive Verghese <cvergh...@openjdk.org> wrote:
> ### Benchmark results
>
> I have benchmarked 3 cases.
>
> 1. The current situation.
>
> Benchmark
> (cipherSuite) Mode Cnt Score Error Units
> CipherSuiteBench.benchmarkCipherSuite
> TLS_AES_256_GCM_SHA384 avgt 25 124.783 ? 2.050 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 avgt 25 125.403 ? 0.554 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_DHE_DSS_WITH_AES_128_CBC_SHA256 avgt 25 127.117 ? 0.789 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_DHE_RSA_WITH_AES_256_CBC_SHA avgt 25 127.869 ? 1.112 ns/op
>
>
> 2. Use `static final array` instead of calling `CipherSuite.values` each
> time.
>
> Benchmark
> (cipherSuite) Mode Cnt Score Error Units
> CipherSuiteBench.benchmarkCipherSuite
> TLS_AES_256_GCM_SHA384 avgt 25 10.146 ? 0.252 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 avgt 25 30.501 ? 0.207 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_DHE_DSS_WITH_AES_128_CBC_SHA256 avgt 25 47.375 ? 0.150 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_DHE_RSA_WITH_AES_256_CBC_SHA avgt 25 55.887 ? 3.786 ns/op
>
>
> 3. Using Hashmap for lookup instead of iterating through the array each time.
> (Method in this PR)
>
> Benchmark
> (cipherSuite) Mode Cnt Score Error Units
> CipherSuiteBench.benchmarkCipherSuite
> TLS_AES_256_GCM_SHA384 avgt 25 13.533 ? 0.148 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 avgt 25 11.269 ? 0.147 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_DHE_DSS_WITH_AES_128_CBC_SHA256 avgt 25 11.507 ? 0.107 ns/op
> CipherSuiteBench.benchmarkCipherSuite
> TLS_DHE_RSA_WITH_AES_256_CBC_SHA avgt 25 10.932 ? 0.146 ns/op
>
>
> I have picked 4 cipher suite from the start of the list and are roughly 10
> positions apart. I have opted to go with HashMap for name and id lookup as
> they provide a more consistent times and benchmarks are similar for the first
> few cipher suits in the enum as well.
The benchmark you provided looks a bit odd... In variant 1 best and worst cases
differ by 3 ns, and in variant 2 they differ by 45 ns. The algorithm is
supposed to be the same, so... Where does the difference come from?
src/java.base/share/classes/sun/security/ssl/CipherSuite.java line 916:
> 914: static String nameOf(int id) {
> 915: if (maps_id.containsKey(id)) {
> 916: return maps_id.get(id).name;
Would it make sense to skip `containsKey` and null-check the value returned by
`get` instead?
-------------
PR: https://git.openjdk.java.net/jdk/pull/4783
