From: art <art@openbsd.org>
Date: Mon, 21 Jul 2008 13:30:04 +0000 (+0000)
Subject: Implement the cpu_yield hypervisor call. Use it in the idle loop for
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=e5499f78036a75ae96c79eb5dd382e3b89e1da30;p=openbsd

Implement the cpu_yield hypervisor call. Use it in the idle loop for
SUN4V to let it suspend strands (why does everyone invent own words for
hyperthreads?). This gives a huge performance boost when most of the
cpus are idle.

kettenis@ ok
---

diff --git a/sys/arch/sparc64/include/hypervisor.h b/sys/arch/sparc64/include/hypervisor.h
index eacf6f2afad..6ef58b8d3d7 100644
--- a/sys/arch/sparc64/include/hypervisor.h
+++ b/sys/arch/sparc64/include/hypervisor.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hypervisor.h,v 1.1 2008/03/08 19:15:56 kettenis Exp $	*/
+/*	$OpenBSD: hypervisor.h,v 1.2 2008/07/21 13:30:04 art Exp $	*/
 
 /*
  * Copyright (c) 2008 Mark Kettenis
@@ -49,6 +49,8 @@ int64_t	hv_cpu_qconf(uint64_t queue, uint64_t base, uint64_t nentries);
 int64_t	hv_cpu_mondo_send(uint64_t ncpus, paddr_t cpulist, paddr_t data);
 int64_t	hv_cpu_myid(uint64_t *cpuid);
 
+void hv_cpu_yield(void);
+
 /*
  * MMU services
  */
diff --git a/sys/arch/sparc64/sparc64/cpu.c b/sys/arch/sparc64/sparc64/cpu.c
index fbd6d202875..193cebcdca4 100644
--- a/sys/arch/sparc64/sparc64/cpu.c
+++ b/sys/arch/sparc64/sparc64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.44 2008/07/12 14:26:07 kettenis Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.45 2008/07/21 13:30:05 art Exp $	*/
 /*	$NetBSD: cpu.c,v 1.13 2001/05/26 21:27:15 chs Exp $ */
 
 /*
@@ -516,3 +516,38 @@ need_resched(struct cpu_info *ci)
 	if (ci->ci_curproc != NULL)
 		aston(ci->ci_curproc);
 }
+
+/*
+ * Idle loop.
+ *
+ * We disable and reenable the interrupts in every cycle of the idle loop.
+ * Since hv_cpu_yield doesn't actually reenable interrupts, it just wakes
+ * up if an interrupt would have happened, but it's our responsibility to
+ * unblock interrupts.
+ */
+
+void
+cpu_idle_enter(void)
+{
+	if (CPU_ISSUN4V) {
+		sparc_wrpr(pstate, sparc_rdpr(pstate) & ~PSTATE_IE, 0);
+	}
+}
+
+void
+cpu_idle_cycle(void)
+{
+	if (CPU_ISSUN4V) {
+		hv_cpu_yield();
+		sparc_wrpr(pstate, sparc_rdpr(pstate) | PSTATE_IE, 0);
+		sparc_wrpr(pstate, sparc_rdpr(pstate) & ~PSTATE_IE, 0);
+	}
+}
+
+void
+cpu_idle_leave()
+{
+	if (CPU_ISSUN4V) {
+		sparc_wrpr(pstate, sparc_rdpr(pstate) | PSTATE_IE, 0);
+	}
+}
diff --git a/sys/arch/sparc64/sparc64/hvcall.S b/sys/arch/sparc64/sparc64/hvcall.S
index ff19183db57..dd27ee8496f 100644
--- a/sys/arch/sparc64/sparc64/hvcall.S
+++ b/sys/arch/sparc64/sparc64/hvcall.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: hvcall.S,v 1.1 2008/03/08 19:15:56 kettenis Exp $	*/
+/*	$OpenBSD: hvcall.S,v 1.2 2008/07/21 13:30:05 art Exp $	*/
 
 /*
  * Copyright (c) 2008 Mark Kettenis
@@ -320,3 +320,9 @@ ENTRY(hv_pci_config_put)
 	ta	FAST_TRAP
 	retl
 	 stx	%o1, [%g5]
+
+ENTRY(hv_cpu_yield)
+	mov	CPU_YIELD, %o5
+	ta	FAST_TRAP
+	retl
+	 nop
diff --git a/sys/arch/sparc64/sparc64/locore.s b/sys/arch/sparc64/sparc64/locore.s
index 756a272622d..81f83cb749a 100644
--- a/sys/arch/sparc64/sparc64/locore.s
+++ b/sys/arch/sparc64/sparc64/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.146 2008/07/12 15:05:51 kettenis Exp $	*/
+/*	$OpenBSD: locore.s,v 1.147 2008/07/21 13:30:05 art Exp $	*/
 /*	$NetBSD: locore.s,v 1.137 2001/08/13 06:10:10 jdolecek Exp $	*/
 
 /*
@@ -6154,18 +6154,6 @@ Lsw_havectx:
 	ret
 	 restore
 
-ENTRY(cpu_idle_enter)
-	retl
-	 nop
-
-ENTRY(cpu_idle_cycle)
-	retl
-	 nop
-
-ENTRY(cpu_idle_leave)
-	retl
-	 nop
-
 /*
  * Snapshot the current process so that stack frames are up to date.
  * Only used just before a crash dump.