overhead of expression evaluation

Hi

just for curiosity - I tested simple script

postgres=# do
$$
declare s bigint = 0;
begin
for i in 1..1000000000 loop
s := s + i;
end loop;
raise notice '%', s;
end;
$$;

to see a overhead of some components

5,72% plpgsql.so [.] exec_assign_value
5,59% postgres [.] GetSnapshotData
4,94% plpgsql.so [.] exec_eval_simple_expr
4,84% postgres [.] AllocSetAlloc
3,61% postgres [.]
ResourceOwnerForgetPlanCacheRef
2,95% postgres [.] choose_custom_plan
2,94% postgres [.] GetUserId
2,92% postgres [.] GetCachedPlan
2,87% postgres [.] LWLockAttemptLock
2,85% postgres [.] memset(at)plt
2,76% postgres [.] LWLockRelease
2,70% postgres [.] AllocSetFree
2,42% plpgsql.so [.] assign_simple_var
2,36% postgres [.] ExecInterpExpr
2,35% postgres [.] PopActiveSnapshot
2,27% postgres [.]
OverrideSearchPathMatchesCurrent
2,22% plpgsql.so [.] plpgsql_param_eval_var
2,21% plpgsql.so [.] exec_stmt
1,89% libc-2.27.so [.]
__memset_sse2_unaligned_erms
1,75% postgres [.] PushActiveSnapshot
1,74% postgres [.] AcquireExecutorLocks
1,67% postgres [.] CopySnapshot
1,64% postgres [.] CheckCachedPlan
1,56% postgres [.] RevalidateCachedQuery
1,55% postgres [.] MemoryContextAlloc
1,53% postgres [.] pfree
1,50% postgres [.] ResourceArrayRemove
1,43% postgres [.] LWLockAcquire
1,40% postgres [.]
SPI_plan_get_cached_plan

Regards

Pavel