Arne Babenhauserheide <arne_...@web.de> writes: > Göran Weinholt <go...@weinholt.se> writes: >> I've pushed a Guile-specific version of (hashing fixnums) that inlines >> the generic arithmetic procedures. This and some other small changes >> improved the runtime: >> >> clock utime stime cutime cstime gctime >> before: >> 2.2.6 31.06 32.61 0.03 0.00 0.00 1.38 >> 2.9.8 15.55 16.23 0.01 0.00 0.00 1.19 >> after: >> 2.2.6 2.95 3.01 0.00 0.00 0.00 0.10 >> 2.9.8 1.98 1.99 0.00 0.00 0.00 0.08 >> >> That's about 100 times slower than sha256sum from coreutils. You might >> get some more performance out of it by unrolling the loop in >> sha-256-transform!. > > I’d like to highlight the understatement: The new version is about > factor 10 faster on 2.2.6 and factor 8 faster on 2.9.8 (and the new > version on Guile 2.9.8 is factor 15 faster than the old version with the > old Guile). > > That’s an awesome speedup! > > (can you show the change/patch that did this? Sidenote: It would be > great to have a list of performance hints for Guile)
The commit is here: https://github.com/weinholt/hashing/commit/eb28080180b5fdfb6ffc74f8cdf2c1a7823ef0cb The relevant changes are: * The define-fx macro previously returned: #'(define name (if (> (fixnum-width) bit-width) fxname bitwise-name)) This was bad for three reasons: Guile does not do constant folding on (fixnum-width); in Guile the fixnum procedures are slower than the generic procedures; and Guile 2.2 did not inline those defines. It now returns: #'(define-syntax name (identifier-syntax bitwise-name)) So the generic procedures like +, bitwise-and, etc are used instead of fx+ and fxand. The use of define-syntax and identifier-syntax is basically manual inlining for the benefit of Guile 2.2. * I replaced some instances of fixnum operations with the ones from (hashing fixnums), which benefit from the above. * I changed some comparisons with constant fixnums to use eqv? instead of fx=?, e.g. (eqv? i 8) instead of (fx=? i 8). This is commonly faster, not only in Guile, because in implementations with immediate fixnums it can be done with only a simple compare + branch. I don't know if Guile takes advantage of this fact, but it's still faster than fx=?. Regards, -- Göran Weinholt | https://weinholt.se/ Debian developer | 73 de SA6CJK
