csc4 -O2 for-each.scm
simple for-each loop over common.log (1799840 lines)
Nursery size 128k
Cache primed
Chicken 4 SVN 14034

Plain Chicken 4:

   ./for-each
   9.843 seconds elapsed 3.399 seconds in (major) GC 3 mutations 6 minor GCs 7657 major GCs 

   ./for-each -:h6m
   6.422 seconds elapsed 0.002 seconds in (major) GC 3 mutations 5753 minor GCs 4 major GCs
	real    0m6.440s user    0m5.788s sys     0m0.646s

With my initial modifications to create a static 1k string buffer for read-line, unsafe:

   7.306 seconds elapsed 1.461 seconds in (major) GC 3 mutations 15 minor GCs 3296 major GCs

   ./for-each -:h6m
   5.839 seconds elapsed 0.001 seconds in (major) GC 3 mutations 1096 minor GCs 1 major GCs

Without the static buffer applied, but changing getc to getc_unlocked:

   7.068 seconds elapsed 3.438 seconds in (major) GC 3 mutations 6 minor GCs 7657 major GCs
        real    0m7.084s user    0m6.431s sys     0m0.648s

   ./for-each -:h6m
   3.563 seconds elapsed 0.001 seconds in (major) GC 3 mutations 5753 minor GCs 4 major GCs

   ./for-each -:s1024k -:h8m 
   3.45 seconds elapsed 0 seconds in (major) GC 3 mutations 5580 minor GCs 0 major GCs 
        real    0m3.468s user    0m2.914s sys     0m0.548s

   ./for-each -:h2m
   3.55 seconds elapsed 0.009 seconds in (major) GC 3 mutations 1417 minor GCs 18 major GCs

   ./for-each -:hi2m
   6.751 seconds elapsed 3.183 seconds in (major) GC 3 mutations 6 minor GCs 7181 major GCs

With static buffer reapplied, and getc_unlocked:

   4.528 seconds elapsed 1.42 seconds in (major) GC 3 mutations 15 minor GCs 3296 major GCs 
        real    0m4.545s user    0m3.947s sys     0m0.593s

   ./for-each -:hi6m  or  -:h6m
   3.063 seconds elapsed 0.002 seconds in (major) GC 3 mutations 1096 minor GCs 1 major GCs
	real    0m3.077s user    0m2.494s sys     0m0.580s

   ./for-each -:s1024k -:h8m 
   2.974 seconds elapsed 0 seconds in (major) GC 3 mutations 3465 minor GCs 0 major GCs 
        real    0m2.989s user    0m2.453s sys     0m0.533s

With correct static buffer, and get_unlocked:

   4.489 seconds elapsed 1.54 seconds in (major) GC 4 mutations 6 minor GCs 3401 major GCs

   ./for-each -:h6m
   2.978 seconds elapsed 0.001 seconds in (major) GC 4 mutations 1160 minor GCs 1 major GCs

   ./for-each -:h6m
   2.887 seconds elapsed 0 seconds in (major) GC 4 mutations 3465 minor GCs 0 major GCs

   ./for-each -:h1m
   2.992 seconds elapsed 0.011 seconds in (major) GC 4 mutations 1482 minor GCs 17 major GCs

--------------------------------------------------------

Read all chars (400M calls) -- getc patch applied

   ./read-char
   100.609 seconds elapsed 0.246 seconds in (major) GC 0 mutations 2312 minor GCs 657 major GCs
   real    1m40.673s user    1m32.302s sys     0m8.316s

Read all chars (400M calls) -- getc patch not applied -- only 10% difference

   111.68 seconds elapsed 0.273 seconds in (major) GC 0 mutations 2312 minor GCs 657 major GCs
   real    1m51.767s user    1m43.315s sys     0m8.376s

--------------------------------------------------------

Linux abbey (VM, disk-bound), pre-patch

   ./for-each
   13.43 seconds elapsed 2.03 seconds in (major) GC 3 mutations 68 minor GCs 1157 major GCs
	real    0m20.308s user    0m11.850s sys     0m1.590s

   ./for-each -:h4m
    9.35 seconds elapsed 0.01 seconds in (major) GC 3 mutations 555 minor GCs 4 major GCs
    real    0m23.415s user    0m8.490s sys     0m0.860s

Linux abbey (probably disk-bound), post-patch

   ./for-each 
   9.65 seconds elapsed    2.18 seconds in (major) GC  4 mutations  66 minor GCs  1163 major GCs
    real    0m18.844suser 0m8.020ssys     0m1.650s

   ./for-each -:h4m
   5.56 seconds elapsed 0 seconds in (major) GC 4 mutations 12021 minor GCs 0 major GCs
   real    0m13.157s user    0m4.820s sys     0m0.740s