Made a tiny bit of progress today. On a bigger machine, I was able to profile the giant unit tests module. It has one top-level for/template that iterates over the 5 scalar types, and a bunch of smaller ones inside that cover the multitude of operations for each of the 4 fixed vector lengths.
profiling (lib "glm/vector/tests.rkt") > Initial code size: 5039 > Final code size : 1019095 > The good news is, I'm seeing around 200x compression. I mean, who wouldn't mind getting completely DRY source for as little as 1/250th the effort? (Assuming, of course, that programming time is proportional to program size in bytes.) The bad news is, compilation takes around 40 seconds on a modern desktop with plenty of CPU and RAM. From the rest of the profiling output, it looks like phase-0 for/template is responsible for about 12.5% of the total size, but phase-1 for/list contributes 57.2% and phase-0 check contributes 48.4%. I'm not sure how to interpret these numbers yet. On one hand, for/template is essentially a for/list loop unroller, so the stats could just mean it did its job. On the other hand, I don't know how much of that 57.2% is merely the cost of doing business in Racket. When I comment out everything but the first two tests, I see this: Initial code size: 243 > Final code size : 21725 > That's a mere 89x compression, which is OK because the first two tests are relatively simple, with phase-0 for/template accounting for 58.5% of the total size, phase-1 for/list contributing 23.2%, and no phase-0 check. It's starting to look like there isn't much I can do to bring down the total size. But what about total compile time? When I manually unroll the for/template forms, the profiler gives: Initial code size: 1509 > Final code size : 21725 > The identical final size is interesting -- it suggests the original output sizes are what they would be if templates weren't used. This version takes, on average, 1.883 seconds to compile. The for/template version takes 2.499 seconds, and an empty test suite takes 1.743 seconds. Subtracting out the control time, it took 0.612 seconds more, or 5.4x longer, to compile a fairly simple module with for/template than without. Is the extra cost acceptable? I'm guessing that's highly context dependent. In this case, adding half a second to compile one module wouldn't inconvenience me terribly, but it doesn't take much imagination to find a situation where it would, and I have no idea how any of these numbers will scale. Eric On Sat, Mar 14, 2020 at 3:28 PM Eric Griffis <ded...@gmail.com> wrote: > Alright, I re-discovered Ryan Culpepper's talk, "The Cost of Sugar," from > the RacketCon 2018 video stream (https://youtu.be/CLjXhr_TgP8?t=5908) and > made some progress by following along. > > Here are the .zo files larger than 100K: > > 993K ./vector/compiled/tests_rkt.zo > 830K ./scribblings/compiled/glm_scrbl.zo > 328K ./vector/compiled/relational_rkt.zo > 295K ./vec4/compiled/bool_rkt.zo > 291K ./vec4/compiled/int_rkt.zo > 290K ./vec4/compiled/uint_rkt.zo > 290K ./vec4/compiled/double_rkt.zo > 289K ./vec4/compiled/float_rkt.zo > 280K ./vec3/compiled/bool_rkt.zo > 276K ./vec3/compiled/int_rkt.zo > 275K ./vec3/compiled/uint_rkt.zo > 275K ./vec3/compiled/double_rkt.zo > 274K ./vec3/compiled/float_rkt.zo > 262K ./vec2/compiled/bool_rkt.zo > 258K ./vec2/compiled/uint_rkt.zo > 258K ./vec2/compiled/int_rkt.zo > 258K ./vec2/compiled/double_rkt.zo > 257K ./vec2/compiled/float_rkt.zo > 213K ./vec1/compiled/bool_rkt.zo > 210K ./vec1/compiled/uint_rkt.zo > 210K ./vec1/compiled/int_rkt.zo > 210K ./vec1/compiled/double_rkt.zo > 209K ./vec1/compiled/float_rkt.zo > 102K ./compiled/main_rkt.zo > 101K ./compiled/vector_rkt.zo > > I'm pretty sure that's a lot of big files. It's for a port of GLM, a > graphics math library that implements (among other things) fixed-length > vectors of up to 4 components over 5 distinct scalar types, for a total of > 20 distinct type-length combinations with many small variations in their > APIs and implementations. > > The variations I'm targeting either require a macro or exacerbate > developer- or run-time overhead when functions are introduced. For example, > the base component accessors for a four-component vector of doubles are: > > dvec4-x > dvec4-y > dvec4-z > dvec4-w > > Each of the "xyzw" components has two aliases -- one from "rgba" and > another from "stpq". Each accessor also has a corresponding mutator, e.g., > dvec4-g and set-dvec4-g!. > > For another example, whereas adding two dvec4's sums four components, > > (dvec4 > (fl+ (dvec4-x v1) (dvec4-x v2)) > (fl+ (dvec4-x v1) (dvec4-x v2)) > (fl+ (dvec4-x v1) (dvec4-x v2)) > (fl+ (dvec4-x v1) (dvec4-x v2))) > > the same operation on dvec2's sums only the first two components. > > Furthermore, the sheer volume of the target code base makes writing > everything out by hand a mind-numbing exercise in frustration, and that's > when looking at a mere 20% of the pile. It's going to get much worse very > quickly. To add fixed-length matrices up to shape 4x4 over the same scalar > types, I'm looking at 16x5 = 80 more distinct type-shape combinations! > > Getting back to the .zo files, I had no luck running "raco macro-profiler" > on the top end of the list. It appears to diverge. My dev laptop probably > doesn't have enough RAM, so I'll have to try again on a bigger machine. > > Here's an excerpt from a file on the bottom end: > > [eric@walden racket-glm]$ raco macro-profiler glm/vec4/double > profiling (lib "glm/vec4/double.rkt") > Initial code size: 87 > Final code size : 86531 > ======================================== > Phase 0 > the-template (defined as the-template.1 in glm/vector/template) > total: 31536, mean: 31536 > direct: 2054, mean: 2054, count: 1, stddev: 0 > define-dvec4-unop (defined in "this module") > total: 7300, mean: 730 > direct: 7480, mean: 748, count: 10, stddev: 0 > define/contract (defined in racket/contract/region) > total: 6666, mean: 44 > direct: 3572, mean: 23, count: 153, stddev: 1.48 > define-dvec4-binop (defined in "this module") > total: 6200, mean: 620 > direct: 6380, mean: 638, count: 10, stddev: 0 > ... > > Phase 1 > for/list (defined in racket/private/for) > total: 6558, mean: 273 > direct: 2274, mean: 95, count: 24, stddev: 14.94 > for/fold/derived/final (defined in racket/private/for) > total: 4332, mean: 180 > direct: 336, mean: 14, count: 24, stddev: 0 > for/fold/derived (defined in racket/private/for) > total: 4284, mean: 178 > direct: 240, mean: 10, count: 24, stddev: 0 > for/foldX/derived (defined in racket/private/for) > total: 3996, mean: 24 > direct: 3164, mean: 19, count: 170, stddev: 48.16 > > Wow, does that look like nearly 1000x compression? Three orders of > magnitude seems right, given what I know about how these macros interact. > > The "the-template" macro is defined inside a module generated by my custom > #%module-begin. It defines 4 type-agnostic, fixed-length module templates > (e.g., glm/vec4/template), which are instantiated once for each of the 5 > scalar types. Those fixed-length module templates are based, in turn, on > another module template (glm/vector/template) that takes a length argument > and uses the other profiled macros (define-dvec4-unop, define/contract, > define-dvec4-binop) to create 20 component-wise operations per instance. > All together, that should inflate the size of the output to somewhere near > the middle of the interval 4x20x5x[1,4], which is 1000. > > At phase 1, the comprehension forms are busy churning out component > aliases and unrolling component-wise operations at "compile" time. I'm > reluctant to anti-inline these because they keep the written code small and > the generated code fast. > > I guess the next step is to anti-inlinedefine-dvec4-unop and > define-dvec4-binop, maybe eliminate some define/contract's, and re-profile. > > Eric > > > On Friday, March 13, 2020 at 6:20:47 PM UTC-7, Eric Griffis wrote: >> >> Hello, >> >> I've got a package that generates (i.e., expands into) a ridiculous >> amount of Racket code. I'd like to generate an unbelievable amount of >> code, but things have already slowed down a lot. >> >> At this point, I'm generating 20% of a massive code base and it takes >> 4 minutes to compile (i.e., raco make) it all. If those numbers scale >> linearly, I'm looking at 20 minutes to generate and compile the full >> code base. Realistically, that's an optimistic lower bound. >> >> How might I go about profiling something that does most of its work at >> expansion time? >> >> Should I be concerned about knocking over or clogging the package >> repository when checking in highly "compressed" meta-programs that >> unfurl at compile time? >> >> Thanks! >> >> Eric >> > -- > 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. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/a0b03065-9626-4555-b29e-6e1ed63691c4%40googlegroups.com > <https://groups.google.com/d/msgid/racket-users/a0b03065-9626-4555-b29e-6e1ed63691c4%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. 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