tthread / windows options

jjallaire · jjallaire · commit 4a89cc4c83b9 · 2014-07-07T15:33:10.000-04:00
diff --git a/R/options.R b/R/options.R
@@ -52,8 +52,13 @@ setThreadOptions <- function(numThreads = "auto", stackSize = "auto") {
    else
       stackSize <- as.integer(stackSize)
    
-   invisible(.Call("setThreadOptions", numThreads, stackSize, 
-                   PACKAGE = "RcppParallel"))
+   if (Sys.info()['sysname'] != "Windows") {
+      invisible(.Call("setThreadOptions", numThreads, stackSize, 
+                      PACKAGE = "RcppParallel"))
+   } 
+   
+   if (numThreads != -1)
+      Sys.setenv(RCPP_PARALLEL_NUM_THREADS = numThreads)
 }
 
 defaultNumThreads <- function() {
diff --git a/inst/include/RcppParallel.h b/inst/include/RcppParallel.h
@@ -31,6 +31,8 @@ struct Worker {
 // tinythread library 
 #include <tthread/tinythread.h>
 
+#include <stdio.h>
+
 #include <vector>
 
 namespace RcppParallel {
@@ -88,9 +90,15 @@ extern "C" inline void workerThread(void* data) {
 // Function to calculate the ranges for a given input
 std::vector<IndexRange> splitInputRange(const IndexRange& range) {
   
-  // max threads is based on hardware concurrency
+  // determine number of threads
   std::size_t threads = tthread::thread::hardware_concurrency();
-  
+  char* numThreads = ::getenv("RCPP_PARALLEL_NUM_THREADS");
+  if (numThreads != NULL) {
+     int parsedThreads = ::atoi(numThreads);
+     if (parsedThreads > 0)
+        threads = parsedThreads;
+  }
+       
   // determine the chunk size
   std::size_t length = range.end() - range.begin();
   std::size_t chunkSize = length / threads;
diff --git a/src/options.cpp b/src/options.cpp
@@ -43,15 +43,13 @@ extern "C" SEXP defaultNumThreads() {
    return threadsSEXP;
 }
 
-#else
+#else // Windows
 
-extern "C" SEXP setThreadOptions(SEXP numThreadsSEXP, SEXP stackSizeSEXP) {
-  return R_NilValue; 
-}
+#include <tthread/tinythread.h>
 
 extern "C" SEXP defaultNumThreads() {
    SEXP threadsSEXP = Rf_allocVector(INTSXP, 1);
-   INTEGER(threadsSEXP)[0] = 4;
+   INTEGER(threadsSEXP)[0] = tthread::thread::hardware_concurrency();
    return threadsSEXP;
 }
 
