Make the scheduler_tick() dependent on the s390 cpu timer so it gets only
called after
a virtual cpu has completed a tick. Together with the virtual sched_clock()
this
should make the scheduler decisions for s390 based on virtual time.
Signed-off-by: Jan Glauber <[EMAIL PROTECTED]>
Signed-off-by: Martin Schwidefsky <[EMAIL PROTECTED]>
---
arch/s390/kernel/time.c | 4 ----
arch/s390/kernel/vtime.c | 7 ++++++-
include/asm-s390/lowcore.h | 8 ++++++--
include/asm-s390/timer.h | 4 ++++
4 files changed, 16 insertions(+), 7 deletions(-)
Index: linux-2.6/include/asm-s390/timer.h
===================================================================
--- linux-2.6.orig/include/asm-s390/timer.h
+++ linux-2.6/include/asm-s390/timer.h
@@ -14,6 +14,10 @@
#include <linux/timer.h>
+/* change this if you have some constant time drift */
+#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
+#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
+
#define VTIMER_MAX_SLICE (0x7ffffffffffff000LL)
struct vtimer_list {
Index: linux-2.6/include/asm-s390/lowcore.h
===================================================================
--- linux-2.6.orig/include/asm-s390/lowcore.h
+++ linux-2.6/include/asm-s390/lowcore.h
@@ -83,6 +83,7 @@
#define __LC_JIFFY_TIMER 0xC80
#define __LC_CURRENT 0xC90
#define __LC_INT_CLOCK 0xC98
+#define __LC_VIRT_TICK 0xCA0
#else /* __s390x__ */
#define __LC_IRB 0x210
#define __LC_SYNC_ENTER_TIMER 0x250
@@ -106,6 +107,7 @@
#define __LC_JIFFY_TIMER 0xDC0
#define __LC_CURRENT 0xDD8
#define __LC_INT_CLOCK 0xDE8
+#define __LC_VIRT_TICK 0xDF0
#endif /* __s390x__ */
@@ -282,7 +284,8 @@ struct _lowcore
__u32 current_task; /* 0xc90 */
__u32 softirq_pending; /* 0xc94 */
__u64 int_clock; /* 0xc98 */
- __u8 pad11[0xe00-0xca0]; /* 0xca0 */
+ __u64 virt_tick; /* 0xca0 */
+ __u8 pad11[0xe00-0xca8]; /* 0xca8 */
/* 0xe00 is used as indicator for dump tools */
/* whether the kernel died with panic() or not */
@@ -374,7 +377,8 @@ struct _lowcore
__u64 current_task; /* 0xdd8 */
__u64 softirq_pending; /* 0xde0 */
__u64 int_clock; /* 0xde8 */
- __u8 pad12[0xe00-0xdf0]; /* 0xdf0 */
+ __u64 virt_tick; /* 0xdf0 */
+ __u8 pad12[0xe00-0xdf8]; /* 0xdf8 */
/* 0xe00 is used as indicator for dump tools */
/* whether the kernel died with panic() or not */
Index: linux-2.6/arch/s390/kernel/time.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/time.c
+++ linux-2.6/arch/s390/kernel/time.c
@@ -40,10 +40,6 @@
#include <asm/timer.h>
#include <asm/etr.h>
-/* change this if you have some constant time drift */
-#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
-#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
-
/* The value of the TOD clock for 1.1.1970. */
#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
Index: linux-2.6/arch/s390/kernel/vtime.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/vtime.c
+++ linux-2.6/arch/s390/kernel/vtime.c
@@ -85,6 +85,7 @@ void account_tick_vtime(struct task_stru
"=m" (S390_lowcore.last_update_clock) );
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
S390_lowcore.steal_clock += S390_lowcore.last_update_clock - clock;
+ S390_lowcore.virt_tick += timer - S390_lowcore.last_update_timer;
cputime = S390_lowcore.user_timer >> 12;
rcu_user_flag = cputime != 0;
@@ -107,7 +108,11 @@ void account_tick_vtime(struct task_stru
run_local_timers();
if (rcu_pending(smp_processor_id()))
rcu_check_callbacks(smp_processor_id(), rcu_user_flag);
- scheduler_tick();
+
+ while (S390_lowcore.virt_tick >= CLK_TICKS_PER_JIFFY) {
+ S390_lowcore.virt_tick -= CLK_TICKS_PER_JIFFY;
+ scheduler_tick();
+ }
run_posix_cpu_timers(tsk);
}
-
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