testsuite: Pass -kb16k -kc128k for performance tests
Setting a larger stack chunk size gives a greater protection from stack thrashing (where the repeated overflow/underflow allocates a lot of stack chunks which sigificantly impact allocations). This stabilises some tests against differences cause by more things being pushed onto the stack. The performance tests are generally testing work done by the compiler, using allocation as a proxy, so removing/stabilising the allocations due to the stack gives us more stable tests which are also more sensitive to actual changes in compiler performance. The tests which increase are ones where we compile a lot of modules, and for each module we spawn a thread to compile the module in. Therefore increasing these numbers has a multiplying effect on these tests because there are many more stacks which we can increase in size. The most significant improvements though are cases such as T8095 which reduce significantly in allocations (30%). This isn't a performance improvement really but just helps stabilise the test against this threshold set by the defaults. Fixes #23439 ------------------------- Metric Decrease: InstanceMatching T14683 T8095 T9872b_defer T9872d T9961 hie002 T19695 T3064 Metric Increase: MultiLayerModules T13701 T14697 -------------------------
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