[m-dev.] Report on --inline-linear-tail-sccs

Paul Bone paul at bone.id.au
Wed Apr 12 22:53:57 AEST 2017

I tried the new --inline-linear-tail-sccs option on Prince and got the
following results.

I used the new tail call warnings to count the number of calls that were
optimised away, which only works in the low level C grade.  However the
optimisation is most relevant for the high level C grade.  So the
performance figures are generated there.  I used GC_MARKERS=1 to make the
scores a bit more reliable.  I used the big_table benchmark.

                       w/o             w (0 extra)     w (1 extra)
No. Mutual calls:          720           127           721  ( A bug? )
Binary size                 Identical.                 (didn't test) 
.text size (bytes)  12,686,779    12,687,099           (didn't test)
User time                   11.2          11.2         (didn't test)

I cannot yet distinguish any performance difference from noise.  Which is to
be expected.  The number of mutual call sites was reduced more than I
expected, a good sign for robustness.


Paul Bone

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