qthreads: add additional configuration options (#15833)

* Add new config options for qthreads

* Fix syntax error and add option for specifying stack size

* Fix flake8 issues

* Add input validation for the stack size variant and add explicit enable for spawn cache

* Fix flake8 issues with input validation code

var/spack/repos/builtin/packages/qthreads/package.py

@@ -6,6 +6,15 @@
 from spack import *
 
 
+def is_integer(x):
+    """Any integer value"""
+
+    try:
+        return float(x).is_integer()
+    except ValueError:
+        return False
+
+
 class Qthreads(AutotoolsPackage):
     """The qthreads API is designed to make using large numbers of
        threads convenient and easy, and to allow portable access to
@@ -33,6 +42,19 @@ class Qthreads(AutotoolsPackage):
         default=True,
         description='hwloc support'
     )
+    variant('spawn_cache',
+            default=False,
+            description='enables worker specific cache of spawns')
+    variant('scheduler', default='nemesis',
+            values=('nemesis', 'lifo', 'mutexfifo', 'mtsfifo',
+                    'sherwood', 'distrib', 'nottingham'),
+            multi=False,
+            description='Specify which scheduler policy to use')
+    variant('static', default=True, description='Build static library')
+    variant('stack_size',
+            default=4096,
+            description='Specify number of bytes to use in a stack',
+            values=is_integer)
 
     depends_on("hwloc@1.0:1.99", when="+hwloc")
 
@@ -45,4 +67,21 @@ def configure_args(self):
                 "--with-hwloc=%s" % spec["hwloc"].prefix]
         else:
             args = ["--with-topology=no"]
+
+        if '+spawn_cache' in self.spec:
+            args.append('--enable-spawn-cache')
+        else:
+            args.append('--disable-spawn-cache')
+
+        if '+static' in self.spec:
+            args.append('--enable-static=yes')
+        else:
+            args.append('--enable-static=no')
+
+        args.append('--with-default-stack-size=%s'
+                    % self.spec.variants['stack_size'].value)
+
+        args.append('--with-scheduler=%s'
+                    % self.spec.variants['scheduler'].value)
+
         return args