diff options
Diffstat (limited to 'meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-timer-fix.patch')
| -rw-r--r-- | meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-timer-fix.patch | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-timer-fix.patch b/meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-timer-fix.patch new file mode 100644 index 000000000..a6f5079fc --- /dev/null +++ b/meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-timer-fix.patch @@ -0,0 +1,64 @@ +From 33725d4939f457b12d7bc1bcbcc0dfb8b2f5bd48 Mon Sep 17 00:00:00 2001 +From: Arjan van de Ven <arjan@linux.intel.com> +Date: Thu, 24 Sep 2009 13:24:16 +0200 +Subject: [PATCH] x86, timers: check for pending timers after (device) interrupts + +Now that range timers and deferred timers are common, I found a +problem with these using the "perf timechart" tool. + +It turns out that on x86, these two 'opportunistic' timers only +get checked when another "real" timer happens. +These opportunistic timers have the objective to save power by +hitchhiking on other wakeups, as to avoid CPU wakeups by themselves +as much as possible. + +The change in this patch runs this check not only at timer interrupts, +but at all (device) interrupts. The effect is that +1) the deferred timers/range timers get delayed less +2) the range timers cause less wakeups by themselves because + the percentage of hitchhiking on existing wakeup events goes up. + +I've verified the working of the patch using "perf timechart", +the original exposed bug is gone with this patch. + +Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> +--- + arch/x86/kernel/irq.c | 2 ++ + arch/x86/kernel/smp.c | 1 + + 2 files changed, 3 insertions(+), 0 deletions(-) + +diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c +index 74656d1..3912061 100644 +--- a/arch/x86/kernel/irq.c ++++ b/arch/x86/kernel/irq.c +@@ -244,6 +244,7 @@ unsigned int __irq_entry do_IRQ(struct pt_regs *regs) + __func__, smp_processor_id(), vector, irq); + } + ++ run_local_timers(); + irq_exit(); + + set_irq_regs(old_regs); +@@ -268,6 +269,7 @@ void smp_generic_interrupt(struct pt_regs *regs) + if (generic_interrupt_extension) + generic_interrupt_extension(); + ++ run_local_timers(); + irq_exit(); + + set_irq_regs(old_regs); +diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c +index ec1de97..d915d95 100644 +--- a/arch/x86/kernel/smp.c ++++ b/arch/x86/kernel/smp.c +@@ -198,6 +198,7 @@ void smp_reschedule_interrupt(struct pt_regs *regs) + { + ack_APIC_irq(); + inc_irq_stat(irq_resched_count); ++ run_local_timers(); + /* + * KVM uses this interrupt to force a cpu out of guest mode + */ +-- +1.6.0.6 + |