[newlib-cygwin] Cygwin: testsuite: Fix for limited thread priority values

[Jon Turney <jturney@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=7d50e65a8442546a6bdce7636d67ad65f154de46

commit 7d50e65a8442546a6bdce7636d67ad65f154de46
Author: Jon Turney <jon.turney@dronecode.org.uk>
Date:   Thu Sep 1 12:13:50 2022 +0100

    Cygwin: testsuite: Fix for limited thread priority values
    
    Since commit 4b51e4c1, we return the actual thread priority, not what we
    originally stored in the thread attributes.
    
    Windows only supports 7 thread priority levels, which we map onto the 32
    required by POSIX.  So, only a subset of values will be returned exactly
    by by pthread_getschedparam() after pthread_setschedparam().
    
    Adjust tests priority1, priority2 and inherit1 so they only check for
    round-tripping priority values which can be exactly represented.
    
    For CI, this needs to handle process priority class "below normal
    priority" as well.
    
    Also check that the range of priority values is at least 32, as required
    by POSIX.
    
    Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>

Diff:
---
 winsup/testsuite/winsup.api/pthread/inherit1.c  | 21 ++++++++++++++++++++-
 winsup/testsuite/winsup.api/pthread/priority1.c | 24 ++++++++++++++++++++++--
 winsup/testsuite/winsup.api/pthread/priority2.c | 22 ++++++++++++++++++++--
 3 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/winsup/testsuite/winsup.api/pthread/inherit1.c b/winsup/testsuite/winsup.api/pthread/inherit1.c
index 16c3f534b..f036462aa 100644
--- a/winsup/testsuite/winsup.api/pthread/inherit1.c
+++ b/winsup/testsuite/winsup.api/pthread/inherit1.c
@@ -50,6 +50,23 @@ void * func(void * arg)
   return (void *) (size_t)param.sched_priority;
 }
 
+// Windows only supports 7 thread priority levels, which we map onto the 32
+// required by POSIX.  The exact mapping also depends on the overall process
+// priority class. So only a subset of values will be returned exactly by
+// pthread_getschedparam() after pthread_setschedparam().
+int doable_pri(int pri)
+{
+  switch (GetPriorityClass(GetCurrentProcess()))
+    {
+    case BELOW_NORMAL_PRIORITY_CLASS:
+      return (pri == 2) || (pri ==  8) || (pri == 10) || (pri == 12) || (pri == 14) || (pri == 16) || (pri == 30);
+    case NORMAL_PRIORITY_CLASS:
+      return (pri == 2) || (pri == 12) || (pri == 14) || (pri == 16) || (pri == 18) || (pri == 20) || (pri == 30);
+    }
+
+  return TRUE;
+}
+
 int
 main()
 {
@@ -81,7 +98,9 @@ main()
       assert(pthread_setschedparam(mainThread, SCHED_FIFO, &mainParam) == 0);
       assert(pthread_getschedparam(mainThread, &policy, &mainParam) == 0);
       assert(policy == SCHED_FIFO);
-      assert(mainParam.sched_priority == prio);
+
+      if (doable_pri(prio))
+        assert(mainParam.sched_priority == prio);
 
       for (param.sched_priority = prio;
            param.sched_priority <= maxPrio;
diff --git a/winsup/testsuite/winsup.api/pthread/priority1.c b/winsup/testsuite/winsup.api/pthread/priority1.c
index a1e8d051d..135f77d76 100644
--- a/winsup/testsuite/winsup.api/pthread/priority1.c
+++ b/winsup/testsuite/winsup.api/pthread/priority1.c
@@ -50,7 +50,24 @@ void * func(void * arg)
   assert(policy == SCHED_FIFO);
   return (void *)(size_t)param.sched_priority;
 }
- 
+
+// Windows only supports 7 thread priority levels, which we map onto the 32
+// required by POSIX.  The exact mapping also depends on the overall process
+// priority class. So only a subset of values will be returned exactly by
+// pthread_getschedparam() after pthread_setschedparam().
+int doable_pri(int pri)
+{
+  switch (GetPriorityClass(GetCurrentProcess()))
+    {
+    case BELOW_NORMAL_PRIORITY_CLASS:
+      return (pri == 2) || (pri ==  8) || (pri == 10) || (pri == 12) || (pri == 14) || (pri == 16) || (pri == 30);
+    case NORMAL_PRIORITY_CLASS:
+      return (pri == 2) || (pri == 12) || (pri == 14) || (pri == 16) || (pri == 18) || (pri == 20) || (pri == 30);
+    }
+
+  return TRUE;
+}
+
 int
 main()
 {
@@ -61,6 +78,8 @@ main()
   int maxPrio = sched_get_priority_max(SCHED_FIFO);
   int minPrio = sched_get_priority_min(SCHED_FIFO);
 
+  assert((maxPrio - minPrio) >= 31);
+
   assert(pthread_attr_init(&attr) == 0);
   assert(pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) == 0);
 
@@ -71,7 +90,8 @@ main()
       assert(pthread_attr_setschedparam(&attr, &param) == 0);
       assert(pthread_create(&t, &attr, func, NULL) == 0);
       pthread_join(t, &result);
-      assert((int)(size_t) result == param.sched_priority);
+      if (doable_pri(param.sched_priority))
+	assert((int)(size_t) result == param.sched_priority);
     }
 
   return 0;
diff --git a/winsup/testsuite/winsup.api/pthread/priority2.c b/winsup/testsuite/winsup.api/pthread/priority2.c
index 0534e7ba1..f084efadf 100644
--- a/winsup/testsuite/winsup.api/pthread/priority2.c
+++ b/winsup/testsuite/winsup.api/pthread/priority2.c
@@ -54,7 +54,24 @@ void * func(void * arg)
   assert(policy == SCHED_FIFO);
   return (void *) (size_t)param.sched_priority;
 }
- 
+
+// Windows only supports 7 thread priority levels, which we map onto the 32
+// required by POSIX.  The exact mapping also depends on the overall process
+// priority class. So only a subset of values will be returned exactly by
+// pthread_getschedparam() after pthread_setschedparam().
+int doable_pri(int pri)
+{
+  switch (GetPriorityClass(GetCurrentProcess()))
+    {
+    case BELOW_NORMAL_PRIORITY_CLASS:
+      return (pri == 2) || (pri ==  8) || (pri == 10) || (pri == 12) || (pri == 14) || (pri == 16) || (pri == 30);
+    case NORMAL_PRIORITY_CLASS:
+      return (pri == 2) || (pri == 12) || (pri == 14) || (pri == 16) || (pri == 18) || (pri == 20) || (pri == 30);
+    }
+
+  return TRUE;
+}
+
 int
 main()
 {
@@ -73,7 +90,8 @@ main()
       assert(pthread_setschedparam(t, SCHED_FIFO, &param) == 0);
       assert(pthread_mutex_unlock(&startMx) == 0);
       pthread_join(t, &result);
-      assert((int)(size_t)result == param.sched_priority);
+      if (doable_pri(param.sched_priority))
+	assert((int)(size_t)result == param.sched_priority);
     }
 
   return 0;