1
0
Fork 0
mirror of https://github.com/ruby/ruby.git synced 2022-11-09 12:17:21 -05:00
ruby--ruby/tool/ruby_vm/models
Alan Wu 89e7997622 Combine call info and cache to speed up method invocation
To perform a regular method call, the VM needs two structs,
`rb_call_info` and `rb_call_cache`. At the moment, we allocate these two
structures in separate buffers. In the worst case, the CPU needs to read
4 cache lines to complete a method call. Putting the two structures
together reduces the maximum number of cache line reads to 2.

Combining the structures also saves 8 bytes per call site as the current
layout uses separate two pointers for the call info and the call cache.
This saves about 2 MiB on Discourse.

This change improves the Optcarrot benchmark at least 3%. For more
details, see attached bugs.ruby-lang.org ticket.

Complications:
 - A new instruction attribute `comptime_sp_inc` is introduced to
 calculate SP increase at compile time without using call caches. At
 compile time, a `TS_CALLDATA` operand points to a call info struct, but
 at runtime, the same operand points to a call data struct. Instruction
 that explicitly define `sp_inc` also need to define `comptime_sp_inc`.
 - MJIT code for copying call cache becomes slightly more complicated.
 - This changes the bytecode format, which might break existing tools.

[Misc #16258]
2019-10-24 18:03:42 +09:00
..
attribute.rb Combine call info and cache to speed up method invocation 2019-10-24 18:03:42 +09:00
bare_instructions.rb Combine call info and cache to speed up method invocation 2019-10-24 18:03:42 +09:00
c_expr.rb
instructions.rb
instructions_unifications.rb
operands_unifications.rb
trace_instructions.rb
typemap.rb Combine call info and cache to speed up method invocation 2019-10-24 18:03:42 +09:00