Author: nwhitehorn
Date: Tue Feb 10 00:55:42 2015
New Revision: 278481
URL: https://svnweb.freebsd.org/changeset/base/278481
Log:
Set thread priorities on multithreaded CPUs so that threads holding a
spinlock are high-priority and threads waiting for a spinlock are set to
low priority.
Modified:
head/sys/powerpc/aim/machdep.c
head/sys/powerpc/include/cpu.h
Modified: head/sys/powerpc/aim/machdep.c
==============================================================================
--- head/sys/powerpc/aim/machdep.c Tue Feb 10 00:48:51 2015
(r278480)
+++ head/sys/powerpc/aim/machdep.c Tue Feb 10 00:55:42 2015
(r278481)
@@ -750,6 +750,7 @@ spinlock_enter(void)
td = curthread;
if (td->td_md.md_spinlock_count == 0) {
+ __asm __volatile("or 2,2,2"); /* Set high thread priority */
msr = intr_disable();
td->td_md.md_spinlock_count = 1;
td->td_md.md_saved_msr = msr;
@@ -768,8 +769,10 @@ spinlock_exit(void)
critical_exit();
msr = td->td_md.md_saved_msr;
td->td_md.md_spinlock_count--;
- if (td->td_md.md_spinlock_count == 0)
+ if (td->td_md.md_spinlock_count == 0) {
intr_restore(msr);
+ __asm __volatile("or 6,6,6"); /* Set normal thread priority */
+ }
}
int db_trap_glue(struct trapframe *); /* Called from trap_subr.S */
Modified: head/sys/powerpc/include/cpu.h
==============================================================================
--- head/sys/powerpc/include/cpu.h Tue Feb 10 00:48:51 2015
(r278480)
+++ head/sys/powerpc/include/cpu.h Tue Feb 10 00:55:42 2015
(r278481)
@@ -88,7 +88,7 @@ get_cyclecount(void)
}
#define cpu_getstack(td) ((td)->td_frame->fixreg[1])
-#define cpu_spinwait() /* nothing */
+#define cpu_spinwait() __asm __volatile("or 27,27,27") /*
yield */
extern char btext[];
extern char etext[];
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