A while ago, I started a thread about whether Rust or C would be a better complement to Racket. After much more Rust research/coding, I got very tired of fighting the compiler, so I decided to blow the dust off my C skills (I haven't done any serious coding in C since 1996), and code up the app in C.
In about 2.5 hours, I had coded as much of the app in C as had taken many more hours in Rust and it was about 2.5x faster and *much* easier to understand. I knew exactly what I wanted to do for maximum performance, but I found myself constantly fighting Rust. I've concluded that, for me, C is a better complement. Anyway, the purpose for this post is to ask for some assistance in getting the best performance out of my Racket code. After choosing a different soundex algorithm, I was a little disappointed in the following runtime numbers for identical functionality: Racket = 10.3s Ruby = 7.61s C = 0.472s Those are numbers for parsing 200K records in a fixed width format to create a postgres bulk input file. The real data contains 45+M records, so speed is a consideration (e.g. 1.8 min. for C vs. 38.6 min. for Racket) It's the fact that Racket is currently slower than Ruby which is bugging me. Despite my rusty (no pun intended) C skills, I was able to hack a version that does zero heap allocation and is pretty speedy, so I wouldn't expect Racket to get close to it. On the other hand, I *would* definitely hope the Racket version can beat the Ruby version. Here are the programs: C: https://gist.github.com/lojic/4369d9d57eb775296c92 Ruby: https://gist.github.com/lojic/2b91fde8e6bbb7bab1cd Racket: https://gist.github.com/lojic/f306104846d516761952 They have identical output (I measured through the first 4M input records), and they are very similar (same functions, etc.) in style. Latest profile output from Racket (using open-output-nowhere as suggested by Vincent): https://gist.githubusercontent.com/lojic/db6e02d0d9d88e1d5ced/raw/1002b6e6ee14f2c59b067abe6eac0488a3f2dc7a/profile.txt Earlier today, I had a hacked up Racket version with manual loops, etc., but then I thought that I really shouldn't have to resort to that to beat Ruby, so I returned the Racket code to a form that was most similar to Ruby. For example: Ruby: def self.parse_string line, beg, len line[beg,len].gsub("\\", '').strip end Racket: (define (parse-string line beg end) (string-trim (string-replace (substring line beg end) "\\" ""))) But I think the Ruby runtime is a little more optimized currently. In particular, I suspect string-replace vs. gsub, string-trim vs. strip, etc. The real fun will come when I use a places version of the Racket code, but I want to get decent linear speed before parallelizing. Ruby has no JIT, and both Ruby and Racket of C runtimes, so there doesn't seem to be any fundamental reason why similar code shouldn't perform better in Racket. By the way, I compared Racket 6.2.1 with 6.3 and the latter is 10.4% faster for this app, so that was encouraging. Any help is greatly appreciated! Brian -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
