When I compile WASH it takes forever for ghc to finish compiling HTMLMonad98, and on my powerpc system with 151MB free RAM, gcc crashes during the compile. Should some of the larger WASH modules maybe be split into multiple files? I get the sense that ghc compilation time/memory is super-linear in the size of the module being compiled.
I've now verified my earlier "ghc compilation complexity is super-linear" belief. I split up HTMLMonad98 into 10 files, and then split the 6th and largest, which consists of the following lines - instance AdmitChildHEAD HTML instance AdmitChildFRAMESET HTML ...(2692 lines) instance AdmitChildLABEL ACRONYM instance AdmitChildBUTTON ACRONYM into 14 files: $ wc -l HTMLMonad98No6.hs 2696 HTMLMonad98No6.hs $ wc -l HTMLMonad98No6?.hs 200 HTMLMonad98No6a.hs 204 HTMLMonad98No6b.hs 204 HTMLMonad98No6c.hs ... 2748 total Compiling a module which imports the 14 smaller modules takes much less time than compiling the monolithic module - it's almost 5 times faster (see below). This is especially strange for this example since it is just a bunch of empty instance declarations. The direct conclusion is that splitting up HTMLMonad98 (5849 lines total) should speed the WASH compile considerably. But this also makes me wonder what the reason for the super-linearity in ghc's compilation time is. Could we fix ghc so that compilation time is mostly linear in the size of modules? Where is the inefficiency? It would seem that at the very least ghc could do a pass extracting strongly connected components of the symbol dependency graph into independent temporary modules, and then compile these pieces separately. Frederik ===== $ time ghc --make HTMLMonad98No6all.hs wash*islay:~/WashNGo-2.4.6-modified/WASH Chasing modules from: HTMLMonad98No6all.hs Skipping HTMLMonad98No5 ( ./HTMLMonad98No5.hs, ./HTMLMonad98No5.o ) Skipping HTMLBase ( ./HTMLBase.hs, ./HTMLBase.o ) Skipping HTMLMonadBase ( ./HTMLMonadBase.hs, ./HTMLMonadBase.o ) Skipping HTMLMonad ( ./HTMLMonad.hs, ./HTMLMonad.o ) Skipping HTMLMonad98No4 ( ./HTMLMonad98No4.hs, ./HTMLMonad98No4.o ) Skipping HTMLMonad98No3 ( ./HTMLMonad98No3.hs, ./HTMLMonad98No3.o ) Skipping HTMLMonad98No2 ( ./HTMLMonad98No2.hs, ./HTMLMonad98No2.o ) Skipping HTMLMonad98No6m ( ./HTMLMonad98No6m.hs, ./HTMLMonad98No6m.o ) Skipping HTMLMonad98No6l ( ./HTMLMonad98No6l.hs, ./HTMLMonad98No6l.o ) Skipping HTMLMonad98No6k ( ./HTMLMonad98No6k.hs, ./HTMLMonad98No6k.o ) Skipping HTMLMonad98No6j ( ./HTMLMonad98No6j.hs, ./HTMLMonad98No6j.o ) Skipping HTMLMonad98No6i ( ./HTMLMonad98No6i.hs, ./HTMLMonad98No6i.o ) Skipping HTMLMonad98No6h ( ./HTMLMonad98No6h.hs, ./HTMLMonad98No6h.o ) Skipping HTMLMonad98No6g ( ./HTMLMonad98No6g.hs, ./HTMLMonad98No6g.o ) Skipping HTMLMonad98No6f ( ./HTMLMonad98No6f.hs, ./HTMLMonad98No6f.o ) Skipping HTMLMonad98No6e ( ./HTMLMonad98No6e.hs, ./HTMLMonad98No6e.o ) Skipping HTMLMonad98No6d ( ./HTMLMonad98No6d.hs, ./HTMLMonad98No6d.o ) Skipping HTMLMonad98No6c ( ./HTMLMonad98No6c.hs, ./HTMLMonad98No6c.o ) Skipping HTMLMonad98No6b ( ./HTMLMonad98No6b.hs, ./HTMLMonad98No6b.o ) Skipping HTMLMonad98No6a ( ./HTMLMonad98No6a.hs, ./HTMLMonad98No6a.o ) Skipping HTMLMonad98No6n ( ./HTMLMonad98No6n.hs, ./HTMLMonad98No6n.o ) Skipping HTMLMonad98No6all ( HTMLMonad98No6all.hs, HTMLMonad98No6all.o ) ghc --make HTMLMonad98No6all.hs 0.26s user 0.04s system 75% cpu 0.396 total $ rm -f *.o $ time ghc --make HTMLMonad98No6all.hs Chasing modules from: HTMLMonad98No6all.hs Compiling HTMLMonad98No5 ( ./HTMLMonad98No5.hs, ./HTMLMonad98No5.o ) Compiling HTMLBase ( ./HTMLBase.hs, ./HTMLBase.o ) Compiling HTMLMonadBase ( ./HTMLMonadBase.hs, ./HTMLMonadBase.o ) Compiling HTMLMonad ( ./HTMLMonad.hs, ./HTMLMonad.o ) Compiling HTMLMonad98No4 ( ./HTMLMonad98No4.hs, ./HTMLMonad98No4.o ) Compiling HTMLMonad98No3 ( ./HTMLMonad98No3.hs, ./HTMLMonad98No3.o ) Compiling HTMLMonad98No2 ( ./HTMLMonad98No2.hs, ./HTMLMonad98No2.o ) Compiling HTMLMonad98No6m ( ./HTMLMonad98No6m.hs, ./HTMLMonad98No6m.o ) Compiling HTMLMonad98No6l ( ./HTMLMonad98No6l.hs, ./HTMLMonad98No6l.o ) Compiling HTMLMonad98No6k ( ./HTMLMonad98No6k.hs, ./HTMLMonad98No6k.o ) Compiling HTMLMonad98No6j ( ./HTMLMonad98No6j.hs, ./HTMLMonad98No6j.o ) Compiling HTMLMonad98No6i ( ./HTMLMonad98No6i.hs, ./HTMLMonad98No6i.o ) Compiling HTMLMonad98No6h ( ./HTMLMonad98No6h.hs, ./HTMLMonad98No6h.o ) Compiling HTMLMonad98No6g ( ./HTMLMonad98No6g.hs, ./HTMLMonad98No6g.o ) Compiling HTMLMonad98No6f ( ./HTMLMonad98No6f.hs, ./HTMLMonad98No6f.o ) Compiling HTMLMonad98No6e ( ./HTMLMonad98No6e.hs, ./HTMLMonad98No6e.o ) Compiling HTMLMonad98No6d ( ./HTMLMonad98No6d.hs, ./HTMLMonad98No6d.o ) Compiling HTMLMonad98No6c ( ./HTMLMonad98No6c.hs, ./HTMLMonad98No6c.o ) Compiling HTMLMonad98No6b ( ./HTMLMonad98No6b.hs, ./HTMLMonad98No6b.o ) Compiling HTMLMonad98No6a ( ./HTMLMonad98No6a.hs, ./HTMLMonad98No6a.o ) Compiling HTMLMonad98No6n ( ./HTMLMonad98No6n.hs, ./HTMLMonad98No6n.o ) Compiling HTMLMonad98No6all ( HTMLMonad98No6all.hs, HTMLMonad98No6all.o ) ghc --make HTMLMonad98No6all.hs 18.12s user 0.31s system 51% cpu 35.452 total $ rm -f *.o $ time ghc --make HTMLMonad98No6.hs Chasing modules from: HTMLMonad98No6.hs Compiling HTMLMonad98No5 ( ./HTMLMonad98No5.hs, ./HTMLMonad98No5.o ) Compiling HTMLBase ( ./HTMLBase.hs, ./HTMLBase.o ) Compiling HTMLMonadBase ( ./HTMLMonadBase.hs, ./HTMLMonadBase.o ) Compiling HTMLMonad ( ./HTMLMonad.hs, ./HTMLMonad.o ) Compiling HTMLMonad98No4 ( ./HTMLMonad98No4.hs, ./HTMLMonad98No4.o ) Compiling HTMLMonad98No3 ( ./HTMLMonad98No3.hs, ./HTMLMonad98No3.o ) Compiling HTMLMonad98No2 ( ./HTMLMonad98No2.hs, ./HTMLMonad98No2.o ) Compiling HTMLMonad98No6 ( HTMLMonad98No6.hs, HTMLMonad98No6.o ) ghc --make HTMLMonad98No6.hs 113.98s user 0.92s system 67% cpu 2:49.65 total $ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Pentium(R) 4 CPU 2.80GHz stepping : 9 cpu MHz : 2794.145 cache size : 512 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr bogomips : 5537.79