The checkmatch instruction with VM_CHECKMATCH_TYPE_CASE calls
=== without a call cache. Emit a send instruction to make the call
instead. It includes a call cache.
The call cache improves throughput of using when statements to check the
class of a given object. This is useful for say, JSON serialization.
Use of a regular send instead of checkmatch also avoids taking the VM
lock every time, which is good for multi-ractor workloads.
Calculating -------------------------------------
master post
vm_case_classes 11.013M 16.172M i/s - 6.000M times in 0.544795s 0.371009s
vm_case_lit 2.296 2.263 i/s - 1.000 times in 0.435606s 0.441826s
vm_case 74.098M 64.338M i/s - 6.000M times in 0.080974s 0.093257s
Comparison:
vm_case_classes
post: 16172114.4 i/s
master: 11013316.9 i/s - 1.47x slower
vm_case_lit
master: 2.3 i/s
post: 2.3 i/s - 1.01x slower
vm_case
master: 74097858.6 i/s
post: 64338333.9 i/s - 1.15x slower
The vm_case benchmark is a bit slower post patch, possibily due to the
larger instruction sequence. The benchmark dispatches using
opt_case_dispatch so was not running checkmatch and does not make the
=== call post patch.
