Duncan Murdoch
2021-Aug-18 14:33 UTC
[Rd] JIT compiler does not compile closures with custom environments
On 18/08/2021 9:00 a.m., Taras Zakharko wrote:> I have encountered a behavior of R?s JIT compiler that I can?t quite figure out. Consider the following code: > > > f_global <- function(x) { > for(i in 1:10000) x <- x + 1 > x > } > > f_env <- local({ > function(x) { > for(i in 1:10000) x <- x + 1 > x > } > }) > > compiler::enableJIT(3) > > bench::mark(f_global(0), f_env(0)) > # 1 f_global(0) 103?s 107.61?s 8770. 11.4KB 0 4384 0 > # 2 f_env(0) 1.1ms 1.42ms 712. 0B 66.3 290 27 > > Inspecting the closures shows that f_global has been byte-compiled while f_env has not been byte-compiled. Furthermore, if I assign a new environment to f_global (e.g. via environment(f_global) <- new.env()), it won?t be byte-compiled either. > > However, if I have a function returning a closure, that closure does get byte-compiled: > > f_closure <- (function() { > function(x) { > for(i in 1:10000) x <- x + 1 > x > } > })() > > bench::mark(f_closure(0)) > # 1 f_closure(0) 105?s 109?s 8625. 0B 2.01 4284 1 497ms > > What is going on here? Both f_closure and f_env have non-global environments. Why is one JIT-compiled, but not the other? Is there a way to ensure that functions defined in environments will be JIT-compiled?About what is going on in f_closure: I think the anonymous factory function() { function(x) { for(i in 1:10000) x <- x + 1 x } } got byte compiled before first use, and that compiled its result. That seems to be what this code indicates: f_closure <- (function() { res <- function(x) { for(i in 1:10000) x <- x + 1 x }; print(res); res })() #> function(x) { #> for(i in 1:10000) x <- x + 1 #> x #> } #> <bytecode: 0x7fb43ec3aa70> #> <environment: 0x7fb441117ac0> But even if that's true, it doesn't address the bigger question of why f_global and f_env are treated differently. Duncan Murdoch
Duncan Murdoch
2021-Aug-18 14:36 UTC
[Rd] JIT compiler does not compile closures with custom environments
Forgot to add: you could define f_env like this to get it compiled:
f_env <- local({
cmpfun(function(x) {
for(i in 1:10000) x <- x + 1
x
})
})
Not as convenient as JIT, but it gets the job done...
Duncan Murdoch
On 18/08/2021 10:33 a.m., Duncan Murdoch wrote:> On 18/08/2021 9:00 a.m., Taras Zakharko wrote:
>> I have encountered a behavior of R?s JIT compiler that I can?t quite
figure out. Consider the following code:
>>
>>
>> f_global <- function(x) {
>> for(i in 1:10000) x <- x + 1
>> x
>> }
>>
>> f_env <- local({
>> function(x) {
>> for(i in 1:10000) x <- x + 1
>> x
>> }
>> })
>>
>> compiler::enableJIT(3)
>>
>> bench::mark(f_global(0), f_env(0))
>> # 1 f_global(0) 103?s 107.61?s 8770. 11.4KB 0
4384 0
>> # 2 f_env(0) 1.1ms 1.42ms 712. 0B 66.3
290 27
>>
>> Inspecting the closures shows that f_global has been byte-compiled
while f_env has not been byte-compiled. Furthermore, if I assign a new
environment to f_global (e.g. via environment(f_global) <- new.env()), it
won?t be byte-compiled either.
>>
>> However, if I have a function returning a closure, that closure does
get byte-compiled:
>>
>> f_closure <- (function() {
>> function(x) {
>> for(i in 1:10000) x <- x + 1
>> x
>> }
>> })()
>>
>> bench::mark(f_closure(0))
>> # 1 f_closure(0) 105?s 109?s 8625. 0B 2.01
4284 1 497ms
>>
>> What is going on here? Both f_closure and f_env have non-global
environments. Why is one JIT-compiled, but not the other? Is there a way to
ensure that functions defined in environments will be JIT-compiled?
>
> About what is going on in f_closure: I think the anonymous factory
>
> function() {
> function(x) {
> for(i in 1:10000) x <- x + 1
> x
> }
> }
>
> got byte compiled before first use, and that compiled its result. That
> seems to be what this code indicates:
>
> f_closure <- (function() {
> res <- function(x) {
> for(i in 1:10000) x <- x + 1
> x
> }; print(res); res
> })()
> #> function(x) {
> #> for(i in 1:10000) x <- x + 1
> #> x
> #> }
> #> <bytecode: 0x7fb43ec3aa70>
> #> <environment: 0x7fb441117ac0>
>
> But even if that's true, it doesn't address the bigger question of
why
> f_global and f_env are treated differently.
>
> Duncan Murdoch
>
iuke-tier@ey m@iii@g oii uiow@@edu
2021-Aug-18 14:45 UTC
[Rd] [External] Re: JIT compiler does not compile closures with custom environments
On Wed, 18 Aug 2021, Duncan Murdoch wrote:> On 18/08/2021 9:00 a.m., Taras Zakharko wrote: >> I have encountered a behavior of R?s JIT compiler that I can?t quite figure >> out. Consider the following code: >> >> >> f_global <- function(x) { >> for(i in 1:10000) x <- x + 1 >> x >> } >> >> f_env <- local({ >> function(x) { >> for(i in 1:10000) x <- x + 1 >> x >> } >> }) >> >> compiler::enableJIT(3) >> >> bench::mark(f_global(0), f_env(0)) >> # 1 f_global(0) 103?s 107.61?s 8770. 11.4KB 0 4384 >> 0 >> # 2 f_env(0) 1.1ms 1.42ms 712. 0B 66.3 290 >> 27 >> Inspecting the closures shows that f_global has been byte-compiled while >> f_env has not been byte-compiled. Furthermore, if I assign a new >> environment to f_global (e.g. via environment(f_global) <- new.env()), it >> won?t be byte-compiled either. >> >> However, if I have a function returning a closure, that closure does get >> byte-compiled: >> >> f_closure <- (function() { >> function(x) { >> for(i in 1:10000) x <- x + 1 >> x >> } >> })() >> >> bench::mark(f_closure(0)) >> # 1 f_closure(0) 105?s 109?s 8625. 0B 2.01 4284 >> 1 497ms >> >> What is going on here? Both f_closure and f_env have non-global >> environments. Why is one JIT-compiled, but not the other? Is there a way to >> ensure that functions defined in environments will be JIT-compiled? > > About what is going on in f_closure: I think the anonymous factory > > function() { > function(x) { > for(i in 1:10000) x <- x + 1 > x > } > } > > got byte compiled before first use, and that compiled its result. That seems > to be what this code indicates: > > f_closure <- (function() { > res <- function(x) { > for(i in 1:10000) x <- x + 1 > x > }; print(res); res > })() > #> function(x) { > #> for(i in 1:10000) x <- x + 1 > #> x > #> } > #> <bytecode: 0x7fb43ec3aa70> > #> <environment: 0x7fb441117ac0>That is right.> But even if that's true, it doesn't address the bigger question of why > f_global and f_env are treated differently.There are various heuristics in the JIT code to avoid spending too much time in the JIT. The current details are in the source code. Mostly this is to deal with usually ill-advised coding practices that programmatically build many small functions. Hopefully these heuristics can be reduced or eliminated over time. For now, putting the code in a package, where the default is to byte compile on source install, or explicitly calling compiler::cmpfun are options. Best, luke> > Duncan Murdoch > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >-- Luke Tierney Ralph E. Wareham Professor of Mathematical Sciences University of Iowa Phone: 319-335-3386 Department of Statistics and Fax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: luke-tierney at uiowa.edu Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu