tree f9bfb5f481a3967eee66603107065fa728602448
parent 08d5e3eb4b2141e1031835c89a62ee3ddf896641
author Anton Blanchard <[EMAIL PROTECTED]> Fri, 08 Jul 2005 07:56:32 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Fri, 08 Jul 2005 08:23:41 -0700
[PATCH] ppc64: iSeries idle fixups
- remove min/max yield time, we dont use the values anywhere
- separate shared and dedicated idle loops
- check need_resched again with irqs off to avoid sleeping with pending work
- continually set runlatch off in idle loop, this means we dont need to
turn the runlatch off on exception exit and suffer that associated
cost for all exceptions. (A future patch will turn the runlatch on at
exception entry)
Signed-off-by: Anton Blanchard <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
arch/ppc64/kernel/iSeries_setup.c | 84 +++++++++++++++++++++-----------------
1 files changed, 47 insertions(+), 37 deletions(-)
diff --git a/arch/ppc64/kernel/iSeries_setup.c
b/arch/ppc64/kernel/iSeries_setup.c
--- a/arch/ppc64/kernel/iSeries_setup.c
+++ b/arch/ppc64/kernel/iSeries_setup.c
@@ -834,9 +834,6 @@ static int __init iSeries_src_init(void)
late_initcall(iSeries_src_init);
-static unsigned long maxYieldTime = 0;
-static unsigned long minYieldTime = 0xffffffffffffffffUL;
-
static inline void process_iSeries_events(void)
{
asm volatile ("li 0,0x5555; sc" : : : "r0", "r3");
@@ -845,7 +842,6 @@ static inline void process_iSeries_event
static void yield_shared_processor(void)
{
unsigned long tb;
- unsigned long yieldTime;
HvCall_setEnabledInterrupts(HvCall_MaskIPI |
HvCall_MaskLpEvent |
@@ -856,13 +852,6 @@ static void yield_shared_processor(void)
/* Compute future tb value when yield should expire */
HvCall_yieldProcessor(HvCall_YieldTimed, tb+tb_ticks_per_jiffy);
- yieldTime = get_tb() - tb;
- if (yieldTime > maxYieldTime)
- maxYieldTime = yieldTime;
-
- if (yieldTime < minYieldTime)
- minYieldTime = yieldTime;
-
/*
* The decrementer stops during the yield. Force a fake decrementer
* here and let the timer_interrupt code sort out the actual time.
@@ -871,45 +860,62 @@ static void yield_shared_processor(void)
process_iSeries_events();
}
-static int iSeries_idle(void)
+static int iseries_shared_idle(void)
{
- struct paca_struct *lpaca;
- long oldval;
+ while (1) {
+ while (!need_resched() && !hvlpevent_is_pending()) {
+ local_irq_disable();
+ ppc64_runlatch_off();
+
+ /* Recheck with irqs off */
+ if (!need_resched() && !hvlpevent_is_pending())
+ yield_shared_processor();
+
+ HMT_medium();
+ local_irq_enable();
+ }
+
+ ppc64_runlatch_on();
+
+ if (hvlpevent_is_pending())
+ process_iSeries_events();
+
+ schedule();
+ }
- /* ensure iSeries run light will be out when idle */
- ppc64_runlatch_off();
+ return 0;
+}
- lpaca = get_paca();
+static int iseries_dedicated_idle(void)
+{
+ struct paca_struct *lpaca = get_paca();
+ long oldval;
while (1) {
- if (lpaca->lppaca.shared_proc) {
- if (hvlpevent_is_pending())
- process_iSeries_events();
- if (!need_resched())
- yield_shared_processor();
- } else {
- oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+ oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+
+ if (!oldval) {
+ set_thread_flag(TIF_POLLING_NRFLAG);
- if (!oldval) {
- set_thread_flag(TIF_POLLING_NRFLAG);
+ while (!need_resched()) {
+ ppc64_runlatch_off();
+ HMT_low();
- while (!need_resched()) {
+ if (hvlpevent_is_pending()) {
HMT_medium();
- if (hvlpevent_is_pending())
- process_iSeries_events();
- HMT_low();
+ ppc64_runlatch_on();
+ process_iSeries_events();
}
-
- HMT_medium();
- clear_thread_flag(TIF_POLLING_NRFLAG);
- } else {
- set_need_resched();
}
+
+ HMT_medium();
+ clear_thread_flag(TIF_POLLING_NRFLAG);
+ } else {
+ set_need_resched();
}
ppc64_runlatch_on();
schedule();
- ppc64_runlatch_off();
}
return 0;
@@ -940,6 +946,10 @@ void __init iSeries_early_setup(void)
ppc_md.get_rtc_time = iSeries_get_rtc_time;
ppc_md.calibrate_decr = iSeries_calibrate_decr;
ppc_md.progress = iSeries_progress;
- ppc_md.idle_loop = iSeries_idle;
+
+ if (get_paca()->lppaca.shared_proc)
+ ppc_md.idle_loop = iseries_shared_idle;
+ else
+ ppc_md.idle_loop = iseries_dedicated_idle;
}
-
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