Hi, So here are the results of `elisp-benchmarks-run' on one "emacs -Q" master and one patched with the attached patch: master: * Results | test | non-gc avg (s) | gc avg (s) | gcs avg | tot avg (s) | tot avg err (s) | |--------------------+----------------+------------+---------+-------------+-----------------| | inclist | 28.16 | 0.00 | 0 | 28.16 | 0.80 | | fibn-rec | 12.89 | 0.00 | 0 | 12.89 | 1.05 | | listlen-tc | 12.68 | 0.00 | 0 | 12.68 | 0.47 | | pack-unpack | 0.28 | 0.21 | 5 | 0.49 | 0.03 | | pidigits | 32.88 | 45.67 | 211 | 78.55 | 0.67 | | map-closure | 16.46 | 0.00 | 0 | 16.46 | 0.74 | | nbody | 5.05 | 17.50 | 416 | 22.56 | 0.94 | | dhrystone | 14.55 | 0.00 | 0 | 14.55 | 2.48 | | pack-unpack-old | 0.75 | 0.47 | 11 | 1.22 | 0.16 | | bubble | 8.54 | 9.90 | 234 | 18.44 | 1.61 | | inclist-type-hints | 28.42 | 0.00 | 0 | 28.42 | 0.55 | | bubble-no-cons | 20.45 | 0.05 | 1 | 20.50 | 1.34 | | fibn | 20.79 | 0.00 | 0 | 20.79 | 1.38 | | fibn-tc | 11.13 | 0.00 | 0 | 11.13 | 0.41 | | pcase | 21.63 | 0.00 | 0 | 21.63 | 0.25 | | flet | 20.92 | 0.00 | 0 | 20.92 | 0.11 | |--------------------+----------------+------------+---------+-------------+-----------------| | total | 255.58 | 73.80 | 878 | 329.38 | 4.10 | patched: * Results | test | non-gc avg (s) | gc avg (s) | gcs avg | tot avg (s) | tot avg err (s) | |--------------------+----------------+------------+---------+-------------+-----------------| | inclist | 27.89 | 0.00 | 0 | 27.89 | 0.20 | | fibn-rec | 11.29 | 0.00 | 0 | 11.29 | 0.20 | | listlen-tc | 12.71 | 0.00 | 0 | 12.71 | 0.98 | | pack-unpack | 0.26 | 0.25 | 10 | 0.51 | 0.04 | | pidigits | 32.27 | 45.05 | 382 | 77.32 | 1.37 | | map-closure | 16.71 | 0.00 | 0 | 16.71 | 1.15 | | nbody | 4.82 | 19.54 | 752 | 24.37 | 1.46 | | dhrystone | 13.38 | 0.00 | 0 | 13.38 | 0.60 | | pack-unpack-old | 0.72 | 0.51 | 20 | 1.23 | 0.08 | | bubble | 8.12 | 10.19 | 400 | 18.30 | 0.92 | | inclist-type-hints | 28.40 | 0.00 | 0 | 28.40 | 0.69 | | bubble-no-cons | 20.75 | 0.08 | 3 | 20.83 | 2.06 | | fibn | 20.04 | 0.00 | 0 | 20.04 | 1.90 | | fibn-tc | 11.02 | 0.00 | 0 | 11.02 | 1.03 | | pcase | 22.31 | 0.00 | 0 | 22.31 | 2.14 | | flet | 21.81 | 0.00 | 0 | 21.81 | 2.18 | |--------------------+----------------+------------+---------+-------------+-----------------| | total | 252.51 | 75.61 | 1568 | 328.13 | 5.13 | It seems that we are in the same ballpark.