From 685db65e422bfa523b8a9dacb5a658b42b254f05 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Thu, 2 Mar 2006 02:54:35 -0800 Subject: [PATCH] time_interpolator: Use readq_relaxed() instead of readq(). On some platforms readq performs additional work to make sure I/O is done in a coherent way. This is not needed for time retrieval as done by the time interpolator. So we can use readq_relaxed instead which will improve performance. It affects sparc64 and ia64 only. Apparently it makes a significant difference on ia64. Signed-off-by: Christoph Lameter Cc: john stultz Cc: "David S. Miller" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/timer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index fe3a9a9f8328..fc6646fd5aab 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1351,10 +1351,10 @@ static inline u64 time_interpolator_get_cycles(unsigned int src) return x(); case TIME_SOURCE_MMIO64 : - return readq((void __iomem *) time_interpolator->addr); + return readq_relaxed((void __iomem *)time_interpolator->addr); case TIME_SOURCE_MMIO32 : - return readl((void __iomem *) time_interpolator->addr); + return readl_relaxed((void __iomem *)time_interpolator->addr); default: return get_cycles(); } -- cgit v1.2.3 From 69239749e1ac4f3496906aa4267cb9f61ce52c9c Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 6 Mar 2006 15:42:45 -0800 Subject: [PATCH] fix next_timer_interrupt() for hrtimer Also from Thomas Gleixner Function next_timer_interrupt() got broken with a recent patch 6ba1b91213e81aa92b5cf7539f7d2a94ff54947c as sys_nanosleep() was moved to hrtimer. This broke things as next_timer_interrupt() did not check hrtimer tree for next event. Function next_timer_interrupt() is needed with dyntick (CONFIG_NO_IDLE_HZ, VST) implementations, as the system can be in idle when next hrtimer event was supposed to happen. At least ARM and S390 currently use next_timer_interrupt(). Signed-off-by: Thomas Gleixner Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/timer.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index fc6646fd5aab..8256f3f5ec0d 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -489,9 +489,21 @@ unsigned long next_timer_interrupt(void) struct list_head *list; struct timer_list *nte; unsigned long expires; + unsigned long hr_expires = MAX_JIFFY_OFFSET; + ktime_t hr_delta; tvec_t *varray[4]; int i, j; + hr_delta = hrtimer_get_next_event(); + if (hr_delta.tv64 != KTIME_MAX) { + struct timespec tsdelta; + tsdelta = ktime_to_timespec(hr_delta); + hr_expires = timespec_to_jiffies(&tsdelta); + if (hr_expires < 3) + return hr_expires + jiffies; + } + hr_expires += jiffies; + base = &__get_cpu_var(tvec_bases); spin_lock(&base->t_base.lock); expires = base->timer_jiffies + (LONG_MAX >> 1); @@ -542,6 +554,10 @@ found: } } spin_unlock(&base->t_base.lock); + + if (time_before(hr_expires, expires)) + return hr_expires; + return expires; } #endif -- cgit v1.2.3 From 5aee405c662ca644980c184774277fc6d0769a84 Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Mon, 6 Mar 2006 15:42:51 -0800 Subject: [PATCH] time: add barrier after updating jiffies_64 Add a compiler barrier so that we don't read jiffies before updating jiffies_64. Signed-off-by: Atsushi Nemoto Cc: Ralf Baechle Cc: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/timer.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index 8256f3f5ec0d..bf7c4193b936 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -941,6 +941,8 @@ static inline void update_times(void) void do_timer(struct pt_regs *regs) { jiffies_64++; + /* prevent loading jiffies before storing new jiffies_64 value. */ + barrier(); update_times(); softlockup_tick(regs); } -- cgit v1.2.3