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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-01-25 21:08:29 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-25 21:08:29 +0100
commit8f4d37ec073c17e2d4aa8851df5837d798606d6f (patch)
treea9ac9063eca53e4d0110e8086f55241ea70ba993 /arch/x86/kernel
parent02b67cc3ba36bdba351d6c3a00593f4ec550d9d3 (diff)
sched: high-res preemption tick
Use HR-timers (when available) to deliver an accurate preemption tick. The regular scheduler tick that runs at 1/HZ can be too coarse when nice level are used. The fairness system will still keep the cpu utilisation 'fair' by then delaying the task that got an excessive amount of CPU time but try to minimize this by delivering preemption points spot-on. The average frequency of this extra interrupt is sched_latency / nr_latency. Which need not be higher than 1/HZ, its just that the distribution within the sched_latency period is important. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/entry_64.S6
-rw-r--r--arch/x86/kernel/signal_32.c3
-rw-r--r--arch/x86/kernel/signal_64.c3
3 files changed, 9 insertions, 3 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 3a058bb1640..e70f3881d7e 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -283,7 +283,7 @@ sysret_careful:
sysret_signal:
TRACE_IRQS_ON
sti
- testl $(_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
+ testl $_TIF_DO_NOTIFY_MASK,%edx
jz 1f
/* Really a signal */
@@ -377,7 +377,7 @@ int_very_careful:
jmp int_restore_rest
int_signal:
- testl $(_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
+ testl $_TIF_DO_NOTIFY_MASK,%edx
jz 1f
movq %rsp,%rdi # &ptregs -> arg1
xorl %esi,%esi # oldset -> arg2
@@ -603,7 +603,7 @@ retint_careful:
jmp retint_check
retint_signal:
- testl $(_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY),%edx
+ testl $_TIF_DO_NOTIFY_MASK,%edx
jz retint_swapgs
TRACE_IRQS_ON
sti
diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 9bdd83022f5..20f29e4c1d3 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -658,6 +658,9 @@ void do_notify_resume(struct pt_regs *regs, void *_unused,
/* deal with pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal(regs);
+
+ if (thread_info_flags & _TIF_HRTICK_RESCHED)
+ hrtick_resched();
clear_thread_flag(TIF_IRET);
}
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index ab086b0357f..38d806467c0 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -480,6 +480,9 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
/* deal with pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
do_signal(regs);
+
+ if (thread_info_flags & _TIF_HRTICK_RESCHED)
+ hrtick_resched();
}
void signal_fault(struct pt_regs *regs, void __user *frame, char *where)