[source]

compiler/codeGen/StgCmmTicky.hs

Note [Ticky for slow calls]

[note link]

Terminology is unfortunately a bit mixed up for these calls. codeGen uses “slow call” to refer to unknown calls and under-saturated known calls.

Nowadays, though (ie as of the eval/apply paper), the significantly slower calls are actually just a subset of these: the ones with no built-in argument pattern (cf StgCmmArgRep.slowCallPattern)

So for ticky profiling, we split slow calls into “SLOW_CALL_fast_<pattern>_ctr” (those matching a built-in pattern) and VERY_SLOW_CALL_ctr (those without a built-in pattern; these are very bad for both space and time).