RFR: 8270317: Large Allocation in CipherSuite
Xin Liu
xliu at openjdk.java.net
Wed Jul 14 21:21:11 UTC 2021
On Wed, 14 Jul 2021 17:06:02 GMT, Clive Verghese <cverghese at 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.
src/java.base/share/classes/sun/security/ssl/CipherSuite.java line 865:
> 863: maps_name.put(cs.name, cs);
> 864: for (String alias : cs.aliases) {
> 865: maps_name.put(alias, cs);
A minor concern here. HashMap can't have duplicate keys. what if there are duplicated names/aliases?
Even it's not the case now, CipherSuite is subject to change in the future and I think it is a good opportunity to detect key duplication here. Currently, it's silently overwritten. This may introduce inconsistent behavior for nameOf.
-------------
PR: https://git.openjdk.java.net/jdk/pull/4783
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