Hi all! Some of my libraries take a while to load: just adding a (require mylib) to an empty #lang racket/base file bumps the compile time from 0.5s to 1.5s, even if no bindings from the library are used. After experimenting a bit, it seems that the overhead is mainly due to other modules which are transitively required (typed/racket, syntax/parse, …).
Assuming that all the files except the main one are already byte-compiled with raco make, what are the factors which affect compile times when a library is (possibly transitively) required? Note that we're talking about milliseconds here, but when a lot of modules are required, these can add up. 1. Number of bindings directly provided? 2. Number of bindings provided by transitively-required modules (including those which are not re-provided, and are not in the main file's namespace) 3. Number of files which are transitively required? 4. Size of the fully expanded code (or size of the bytecode)? 5. Compile-time operations, e.g. within a begin-for-syntax in a (transitively-)required module? 6. When a module is required at several meta-levels, does it affect the compile time significantly, or is it roughly the same cost than requiring it only once? 7. Something else? Point 5 seems to matter, as compiling a.rkt still prints "Hello" even if b.rkt is already compiled: a.rkt: #lang racket/base (require "b.rkt") b.rkt: #lang racket/base (require (for-syntax racket/base)) (begin-for-syntax (displayln "Hello")) However, I'm not sure what operations can cause compile-time code to be run in this situation. My (possibly incorrect) understanding is that macros are executed only once (when expanding the code), but the code to the right-hand-side of a (define-syntax foo costly-operation), and the code within a (begin-for-syntax …) will both be run each time the module is required. What I would like is to learn a few "good practices" and gotchas concerning compile-time performance. -- 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 racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
