In brodieG/matchcall: Match Calls From Dynamic Stack

Benchmarks

Just the bare call to the C function including the calls to sys.frames and sys.calls takes as long as match.call. Here we've changed match_call() to return R_NilValue at the first function line:

fun <- function(x, y, z=TRUE) match_call()
fun2 <- function(x, y, z=TRUE) match.call()

library(microbenchmark)
microbenchmark(fun(1, 2, 3), fun2(1, 2, 3))

Produces

Unit: microseconds
          expr   min    lq median    uq     max neval
  fun(1, 2, 3) 2.416 2.746 3.0710 3.474 137.333   100
 fun2(1, 2, 3) 2.204 2.475 2.6925 2.969  11.608   100

With "normal" match_call (as of commit 71355fb), we get:

Unit: microseconds
          expr   min     lq median     uq     max neval
  fun(1, 2, 3) 4.521 5.2715 5.6135 6.0715 131.933   100
 fun2(1, 2, 3) 2.315 2.6755 3.0280 3.3140  21.376   100

There is probably room for improvement, but given that we eval match.call from within match_call, it's hard to imagine it will get that much better. The actual match.call call inside match_call looks to take about 1.2us:

Exiting right before match.call:

Unit: microseconds
         expr   min    lq median     uq     max neval
 fun(1, 2, 3) 3.004 3.292  3.513 3.8445 171.104  2000

Exiting right after

Unit: microseconds
         expr   min     lq median    uq    max neval
 fun(1, 2, 3) 4.243 4.7125  4.994 5.412 41.397  2000

So maybe we can save half a microsecond someplace, or if really necessary code the match.call logic ourselves, though that will be a PITA.

Comparing whether to send sys.calls or to run from C via install/eval

• mc_test1 is sending list(sys.calls(), sys.frames(), sys.parents())
• mc_test2 is evaling the above in C
• mc_test3 is like 1, but instead of using list sending each arg separately

> microbenchmark(mc_test1(), mc_test2(), mc_test3(), times=1000)
Unit: microseconds
       expr   min     lq median    uq    max neval
 mc_test1() 1.501 1.6210  1.742 1.935 89.230  1000
 mc_test2() 1.054 1.1470  1.212 1.369 99.947  1000
 mc_test3() 1.378 1.4985  1.596 1.802 44.213  1000

brodieG/matchcall documentation built on May 13, 2019, 7:46 a.m.