RFR: improve warmup time for lambda capture

Sergey Kuksenko sergey.kuksenko at oracle.com
Wed Aug 21 09:41:02 PDT 2013


Please review the webrev at:


Also I need a sponsor to commit.

   The issue with lambda capture warmup is related to current jsr292
   Lambda metafactory creates call site which points to (MethodHandle)
lambda generated class constructor. Invocation of the constructor is
performed via some generated call chain (jsr292 implementation
specific). When C1 or C2 compiles it - all these methods are inlined and
code is clean, but interpretation is relatively slow. Such jsr292 call
chain for static methods (MH to static method) is simpler than to
constructor that is why it is warmed up faster.
The patch generated static factory method for lambda capture in each
generated class and links CallSite to the static factory method.
   Attached charts shows warmup improvement (both tiered and non-tiered
compilation). The benchmark creates 4000 different lambdas, each lambda
captures one variable.
  Of course this improvement is implementation specific and depends on
jsr292 implementation. In future (when/if jsr292 will warmup MH to
constructor with the same speed as MH to static method) we may revert it

Best regards,
Sergey Kuksenko

More information about the lambda-dev mailing list