More benchmark tweaks

cpp11test/R/cpp11.R

@@ -224,6 +224,10 @@ rcpp_grow_ <- function(n_sxp) {
   .Call(`_cpp11test_rcpp_grow_`, n_sxp)
 }
 
+rcpp_push_and_truncate_ <- function(size_sxp) {
+  .Call(`_cpp11test_rcpp_push_and_truncate_`, size_sxp)
+}
+
 test_destruction_inner <- function() {
   invisible(.Call(`_cpp11test_test_destruction_inner`))
 }

cpp11test/bench/truncate.R

@@ -3,15 +3,18 @@ pkgload::load_all("cpp11test")
 bench::press(len = as.integer(10 ^ (0:6)),
   {
     bench::mark(
-      cpp11_push_and_truncate_(len),
-      min_iterations = 100
+      cpp11 = cpp11_push_and_truncate_(len),
+      rcpp = rcpp_push_and_truncate_(len),
+      check = FALSE,
+      min_iterations = 1000
     )
   }
-)
+)[c("expression", "len", "min", "mem_alloc", "n_itr", "n_gc")]
 
 # Longer benchmark, lots of gc
 len <- as.integer(10 ^ 7)
 bench::mark(
-  cpp11_push_and_truncate_(len),
+  cpp11 = cpp11_push_and_truncate_(len),
+  rcpp = rcpp_push_and_truncate_(len),
   min_iterations = 200
-)
+)[c("expression", "min", "mem_alloc", "n_itr", "n_gc")]

cpp11test/src/cpp11.cpp

@@ -422,6 +422,13 @@ extern "C" SEXP _cpp11test_rcpp_grow_(SEXP n_sxp) {
     return cpp11::as_sexp(rcpp_grow_(cpp11::as_cpp<cpp11::decay_t<SEXP>>(n_sxp)));
   END_CPP11
 }
+// sum_rcpp.cpp
+SEXP rcpp_push_and_truncate_(SEXP size_sxp);
+extern "C" SEXP _cpp11test_rcpp_push_and_truncate_(SEXP size_sxp) {
+  BEGIN_CPP11
+    return cpp11::as_sexp(rcpp_push_and_truncate_(cpp11::as_cpp<cpp11::decay_t<SEXP>>(size_sxp)));
+  END_CPP11
+}
 // test-protect-nested.cpp
 void test_destruction_inner();
 extern "C" SEXP _cpp11test_test_destruction_inner() {
@@ -489,6 +496,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"_cpp11test_protect_one_preserve_",    (DL_FUNC) &_cpp11test_protect_one_preserve_,    2},
     {"_cpp11test_protect_one_sexp_",        (DL_FUNC) &_cpp11test_protect_one_sexp_,        2},
     {"_cpp11test_rcpp_grow_",               (DL_FUNC) &_cpp11test_rcpp_grow_,               1},
+    {"_cpp11test_rcpp_push_and_truncate_",  (DL_FUNC) &_cpp11test_rcpp_push_and_truncate_,  1},
     {"_cpp11test_rcpp_release_",            (DL_FUNC) &_cpp11test_rcpp_release_,            1},
     {"_cpp11test_rcpp_sum_dbl_accumulate_", (DL_FUNC) &_cpp11test_rcpp_sum_dbl_accumulate_, 1},
     {"_cpp11test_rcpp_sum_dbl_for_",        (DL_FUNC) &_cpp11test_rcpp_sum_dbl_for_,        1},

cpp11test/src/sum_rcpp.cpp

@@ -56,3 +56,15 @@
 
   return x;
 }
+
+[[cpp11::register]] SEXP rcpp_push_and_truncate_(SEXP size_sxp) {
+  R_xlen_t size = INTEGER(size_sxp)[0];
+
+  // Allocate `size` worth of doubles (filled with garbage data)
+  Rcpp::NumericVector out(size);
+
+  // Push 1 more past the existing capacity
+  out.push_back(0);
+
+  return out;
+}

cpp11test/src/truncate.cpp

@@ -3,15 +3,11 @@
 [[cpp11::register]] SEXP cpp11_push_and_truncate_(SEXP size_sexp) {
   R_xlen_t size = INTEGER(size_sexp)[0];
 
+  // Allocate `size` worth of doubles (filled with garbage data)
   cpp11::writable::doubles out(size);
 
-  // Fill it
-  for (R_xlen_t i = 0; i < size; ++i) {
-    out.push_back(0);
-  }
-
-  // Push 1 more past the existing capacity,
-  // doubling the capacity
+  // Push 1 more past the existing length/capacity,
+  // doubling the capacity for cpp11 vectors
   out.push_back(0);
 
   // Truncate back to `size + 1` size and return result.