Hi Xuelei,
The JMH benchmark code is at
http://cr.openjdk.java.net/~mbalao/webrevs/8223482/ciphersuites_benchmark_v0.tar.gz
Once the crypto providers and SSL engines are initialized, the following
sequence is measured:
1) Client and Server perform a handshake until status is
HandshakeStatus.FINISHED on both ends
2) Server renegotiates the session (SSLEngine.beginHandshake is called)
so the sequence repeats.
See test_TLS12Communication method in
ciphersuites/src/main/java/org/redhat/SupportedCiphersuites.java.
Webrev.00 was affecting performance because in each TLS handshake, the
client was testing ciphersuites before moving forward. In Webrev.01 a
performance impact is not seen here because ciphersuites checking occurs
only at SSLContextImpl static class initialization time (not per
instance but per static class initializer). Thus, to have a performance
impact we would need the class loader to get rid of SSLContextImpl class
-subclasses to be accurate- and load it again in every loop -which would
make no sense-.
Here it's a call stack when "SSLContextImpl.getApplicableCipherSuites"
gets executed:
Thread [main] (Suspended (breakpoint at line 374 in SSLContextImpl))
SSLContextImpl.getApplicableCipherSuites(Collection<CipherSuite>,
List<ProtocolVersion>) line: 374
SSLContextImpl.getApplicableSupportedCipherSuites(List<ProtocolVersion>)
line: 339
SSLContextImpl$AbstractTLSContext.<clinit>() line: 555
Class<T>.forName0(String, boolean, ClassLoader, Class<?>) line: not
available [native method]
Class<T>.forName(String) line: 333
Provider$Service.getImplClass() line: 1842
Provider$Service.newInstance(Object) line: 1818
GetInstance.getInstance(Service, Class<?>) line: 236
GetInstance.getInstance(String, Class<?>, String, String) line: 206
SSLContext.getInstance(String, String) line: 229
SupportedCiphersuites.createSSLEngine(boolean) line: 273
SupportedCiphersuites.createSSLEngines() line: 256
SupportedCiphersuites.initialize() line: 239
SupportedCiphersuites.main(String[]) line: 71
You see there how "SSLContextImpl$AbstractTLSContext.<clinit>()" static
initializer is in the call stack.
I've not found any possible execution path to
"SSLContextImpl.getApplicableCipherSuites" that does not come from a
static class initializer.
Thanks,
Martin.-
