From: Matt Porter <mporter@kernel.crashing.org>
The following patch fixes the situation where the loop condition could
generate a next_dec of zero while exiting the loop. This is suboptimal on
Classic PPC because it forces another interrupt to occur and reenter the
handler. It is fatal on Book E cores, because their decrementer is stopped
when writing a zero (Classic interrupts on a 0->-1 transition, Book E
interrupts on a 1->0 transition). Instead, stay in the loop on a
next_dec==0.
Signed-off-by: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/ppc/kernel/time.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN arch/ppc/kernel/time.c~ppc32-optimize-fix-timer_interrupt-loop arch/ppc/kernel/time.c
--- 25/arch/ppc/kernel/time.c~ppc32-optimize-fix-timer_interrupt-loop Mon Aug 9 14:17:30 2004
+++ 25-akpm/arch/ppc/kernel/time.c Mon Aug 9 14:17:30 2004
@@ -161,7 +161,7 @@ void timer_interrupt(struct pt_regs * re
irq_enter();
- while ((next_dec = tb_ticks_per_jiffy - tb_delta(&jiffy_stamp)) < 0) {
+ while ((next_dec = tb_ticks_per_jiffy - tb_delta(&jiffy_stamp)) <= 0) {
jiffy_stamp += tb_ticks_per_jiffy;
ppc_do_profile(regs);
_