Cygwin: implement sched_getcpu

* create new function __get_cpus_per_group to evaluate # of CPU groups
* Call from  format_proc_cpuinfo and sched_getcpu
* Bump API minor version

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

1 files changed, 53 insertions, 0 deletions

diff --git a/winsup/cygwin/miscfuncs.cc b/winsup/cygwin/miscfuncs.cc
index 3ad658739..b5dfffc7d 100644
--- a/winsup/cygwin/miscfuncs.cc
+++ b/winsup/cygwin/miscfuncs.cc
@@ -15,6 +15,7 @@ details. */
 #include "path.h"
 #include "fhandler.h"
 #include "exception.h"
+#include "tls_pbuf.h"
 
 int __reg2
 check_invalid_virtual_addr (const void *s, unsigned sz)
@@ -959,3 +960,55 @@ SetThreadName(DWORD dwThreadID, const char* threadName)
   __except (NO_ERROR)
   __endtry
 }
+
+#define add_size(p,s) ((p) = ((__typeof__(p))((PBYTE)(p)+(s))))
+
+WORD
+__get_cpus_per_group (void)
+{
+  static WORD num_cpu_per_group = 0;
+
+  tmp_pathbuf tp;
+
+  if (num_cpu_per_group)
+    return num_cpu_per_group;
+
+  num_cpu_per_group = 64;
+
+  PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX lpi =
+            (PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX) tp.c_get ();
+  DWORD lpi_size = NT_MAX_PATH;
+
+  /* Fake a SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX group info block on Vista
+     systems.  This may be over the top but if the below code just using
+     ActiveProcessorCount turns out to be insufficient, we can build on that. */
+  if (!wincap.has_processor_groups ()
+      || !GetLogicalProcessorInformationEx (RelationGroup, lpi, &lpi_size))
+    {
+      lpi_size = sizeof *lpi;
+      lpi->Relationship = RelationGroup;
+      lpi->Size = lpi_size;
+      lpi->Group.MaximumGroupCount = 1;
+      lpi->Group.ActiveGroupCount = 1;
+      lpi->Group.GroupInfo[0].MaximumProcessorCount = wincap.cpu_count ();
+      lpi->Group.GroupInfo[0].ActiveProcessorCount
+        = __builtin_popcountl (wincap.cpu_mask ());
+      lpi->Group.GroupInfo[0].ActiveProcessorMask = wincap.cpu_mask ();
+    }
+
+  PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX plpi = lpi;
+  for (DWORD size = lpi_size; size > 0;
+       size -= plpi->Size, add_size (plpi, plpi->Size))
+    if (plpi->Relationship == RelationGroup)
+      {
+        /* There are systems with a MaximumProcessorCount not reflecting the
+	   actually available CPUs.  The ActiveProcessorCount is correct
+	   though.  So we just use ActiveProcessorCount for now, hoping for
+	   the best. */
+        num_cpu_per_group
+                = plpi->Group.GroupInfo[0].ActiveProcessorCount;
+        break;
+      }
+
+  return num_cpu_per_group;
+}