Linus, please pull the latest x86 git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git
This contains 3 x86/hrtimer/hpet/ACPI fixes from Thomas: the ACPI fix
has been ACK-ed by Venki. Build and boot tested on various boxes.
Ingo
------------------>
Thomas Gleixner (3):
hrtimers: avoid overflow for large relative timeouts
clockevents: warn once when program_event() is called with negative expiry
ACPI: move timer broadcast before busmaster disable
drivers/acpi/processor_idle.c | 19 ++++++++++++++-----
kernel/hrtimer.c | 8 ++++++++
kernel/time/clockevents.c | 5 +++++
3 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index b1fbee3..2fe34cc 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -531,6 +531,11 @@ static void acpi_processor_idle(void)
case ACPI_STATE_C3:
/*
+ * Must be done before busmaster disable as we might
+ * need to access HPET !
+ */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ /*
* disable bus master
* bm_check implies we need ARB_DIS
* !bm_check implies we need cache flush
@@ -557,7 +562,6 @@ static void acpi_processor_idle(void)
/* Get start time (ticks) */
t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
/* Invoke C3 */
- acpi_state_timer_broadcast(pr, cx, 1);
/* Tell the scheduler that we are going deep-idle: */
sched_clock_idle_sleep_event();
acpi_cstate_enter(cx);
@@ -1401,9 +1405,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
if (acpi_idle_suspend)
return(acpi_idle_enter_c1(dev, state));
- if (pr->flags.bm_check)
- acpi_idle_update_bm_rld(pr, cx);
-
local_irq_disable();
current_thread_info()->status &= ~TS_POLLING;
/*
@@ -1418,13 +1419,21 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
return 0;
}
+ /*
+ * Must be done before busmaster disable as we might need to
+ * access HPET !
+ */
+ acpi_state_timer_broadcast(pr, cx, 1);
+
+ if (pr->flags.bm_check)
+ acpi_idle_update_bm_rld(pr, cx);
+
if (cx->type == ACPI_STATE_C3)
ACPI_FLUSH_CPU_CACHE();
t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
/* Tell the scheduler that we are going deep-idle: */
sched_clock_idle_sleep_event();
- acpi_state_timer_broadcast(pr, cx, 1);
acpi_idle_do_entry(cx);
t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 22a2514..e65dd0b 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -850,6 +850,14 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
#ifdef CONFIG_TIME_LOW_RES
tim = ktime_add(tim, base->resolution);
#endif
+ /*
+ * Careful here: User space might have asked for a
+ * very long sleep, so the add above might result in a
+ * negative number, which enqueues the timer in front
+ * of the queue.
+ */
+ if (tim.tv64 < 0)
+ tim.tv64 = KTIME_MAX;
}
timer->expires = tim;
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 822beeb..5fb139f 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -78,6 +78,11 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
unsigned long long clc;
int64_t delta;
+ if (unlikely(expires.tv64 < 0)) {
+ WARN_ON_ONCE(1);
+ return -ETIME;
+ }
+
delta = ktime_to_ns(ktime_sub(expires, now));
if (delta <= 0)
On Fri, 2007-12-07 at 19:36 +0100, Ingo Molnar wrote:
> Linus, please pull the latest x86 git tree from:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git
>
> This contains 3 x86/hrtimer/hpet/ACPI fixes from Thomas: the ACPI fix
> has been ACK-ed by Venki. Build and boot tested on various boxes.
Ingo, I was about to post about timer problems in 2.6.23.9+rt12 when I
saw this. Would this be related / should I test / will this solve
everything? :-)
What I'm seeing is jack "delays" that go away if I boot with
"idle=poll", just like it was happening a long time ago. Smells like
'time of day' glitches when the process switches cpus (this is on a dual
core intel laptop).
Does not happen in 2.6.22.10 + rt9 - well, I do see very occassional
delay warnings there as well.
I also see occassional complete hangs but I don't have a way of knowing
what triggers that.
-- Fernando
> ------------------>
> Thomas Gleixner (3):
> hrtimers: avoid overflow for large relative timeouts
> clockevents: warn once when program_event() is called with negative expiry
> ACPI: move timer broadcast before busmaster disable
>
> drivers/acpi/processor_idle.c | 19 ++++++++++++++-----
> kernel/hrtimer.c | 8 ++++++++
> kernel/time/clockevents.c | 5 +++++
> 3 files changed, 27 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index b1fbee3..2fe34cc 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -531,6 +531,11 @@ static void acpi_processor_idle(void)
>
> case ACPI_STATE_C3:
> /*
> + * Must be done before busmaster disable as we might
> + * need to access HPET !
> + */
> + acpi_state_timer_broadcast(pr, cx, 1);
> + /*
> * disable bus master
> * bm_check implies we need ARB_DIS
> * !bm_check implies we need cache flush
> @@ -557,7 +562,6 @@ static void acpi_processor_idle(void)
> /* Get start time (ticks) */
> t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
> /* Invoke C3 */
> - acpi_state_timer_broadcast(pr, cx, 1);
> /* Tell the scheduler that we are going deep-idle: */
> sched_clock_idle_sleep_event();
> acpi_cstate_enter(cx);
> @@ -1401,9 +1405,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
> if (acpi_idle_suspend)
> return(acpi_idle_enter_c1(dev, state));
>
> - if (pr->flags.bm_check)
> - acpi_idle_update_bm_rld(pr, cx);
> -
> local_irq_disable();
> current_thread_info()->status &= ~TS_POLLING;
> /*
> @@ -1418,13 +1419,21 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
> return 0;
> }
>
> + /*
> + * Must be done before busmaster disable as we might need to
> + * access HPET !
> + */
> + acpi_state_timer_broadcast(pr, cx, 1);
> +
> + if (pr->flags.bm_check)
> + acpi_idle_update_bm_rld(pr, cx);
> +
> if (cx->type == ACPI_STATE_C3)
> ACPI_FLUSH_CPU_CACHE();
>
> t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
> /* Tell the scheduler that we are going deep-idle: */
> sched_clock_idle_sleep_event();
> - acpi_state_timer_broadcast(pr, cx, 1);
> acpi_idle_do_entry(cx);
> t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>
> diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
> index 22a2514..e65dd0b 100644
> --- a/kernel/hrtimer.c
> +++ b/kernel/hrtimer.c
> @@ -850,6 +850,14 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
> #ifdef CONFIG_TIME_LOW_RES
> tim = ktime_add(tim, base->resolution);
> #endif
> + /*
> + * Careful here: User space might have asked for a
> + * very long sleep, so the add above might result in a
> + * negative number, which enqueues the timer in front
> + * of the queue.
> + */
> + if (tim.tv64 < 0)
> + tim.tv64 = KTIME_MAX;
> }
> timer->expires = tim;
>
> diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
> index 822beeb..5fb139f 100644
> --- a/kernel/time/clockevents.c
> +++ b/kernel/time/clockevents.c
> @@ -78,6 +78,11 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
> unsigned long long clc;
> int64_t delta;
>
> + if (unlikely(expires.tv64 < 0)) {
> + WARN_ON_ONCE(1);
> + return -ETIME;
> + }
> +
> delta = ktime_to_ns(ktime_sub(expires, now));
>
> if (delta <= 0)
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
* Fernando Lopez-Lezcano <[email protected]> wrote:
> Ingo, I was about to post about timer problems in 2.6.23.9+rt12 when I
> saw this. Would this be related / should I test / will this solve
> everything? :-)
>
> What I'm seeing is jack "delays" that go away if I boot with
> "idle=poll", just like it was happening a long time ago. Smells like
> 'time of day' glitches when the process switches cpus (this is on a
> dual core intel laptop).
does it go away with hpet=disable as well? If yes then there could be a
relation. If not then it's something else and we need to debug it.
Ingo
On Fri, 2007-12-07 at 19:59 +0100, Ingo Molnar wrote:
> * Fernando Lopez-Lezcano <[email protected]> wrote:
>
> > Ingo, I was about to post about timer problems in 2.6.23.9+rt12 when I
> > saw this. Would this be related / should I test / will this solve
> > everything? :-)
> >
> > What I'm seeing is jack "delays" that go away if I boot with
> > "idle=poll", just like it was happening a long time ago. Smells like
> > 'time of day' glitches when the process switches cpus (this is on a
> > dual core intel laptop).
>
> does it go away with hpet=disable as well? If yes then there could be a
> relation. If not then it's something else and we need to debug it.
Nope, it doesn't still getting "delay" and "xrun" messages galore.
-- Fernando
On Fri, 2007-12-07 at 11:29 -0800, Fernando Lopez-Lezcano wrote:
> On Fri, 2007-12-07 at 19:59 +0100, Ingo Molnar wrote:
> > * Fernando Lopez-Lezcano <[email protected]> wrote:
> >
> > > Ingo, I was about to post about timer problems in 2.6.23.9+rt12 when I
> > > saw this. Would this be related / should I test / will this solve
> > > everything? :-)
> > >
> > > What I'm seeing is jack "delays" that go away if I boot with
> > > "idle=poll", just like it was happening a long time ago. Smells like
> > > 'time of day' glitches when the process switches cpus (this is on a
> > > dual core intel laptop).
> >
> > does it go away with hpet=disable as well? If yes then there could be a
> > relation. If not then it's something else and we need to debug it.
>
> Nope, it doesn't still getting "delay" and "xrun" messages galore.
Attached: configuration and dmesg output booting with idle=poll,
reconfirmed that that makes the delay and xrun messages go away.
-- Fernando
* Fernando Lopez-Lezcano <[email protected]> wrote:
> > Nope, it doesn't still getting "delay" and "xrun" messages galore.
>
> Attached: configuration and dmesg output booting with idle=poll,
> reconfirmed that that makes the delay and xrun messages go away.
could you try the rolled up patch of various fixlets, ontop of current
-git? (it might even apply to -rc4) It includes some more stuff beyond
the ones in the pull request. (still being tested/reviewed)
Ingo
Index: linux/arch/arm/kernel/time.c
===================================================================
--- linux.orig/arch/arm/kernel/time.c
+++ linux/arch/arm/kernel/time.c
@@ -79,17 +79,6 @@ static unsigned long dummy_gettimeoffset
}
#endif
-/*
- * An implementation of printk_clock() independent from
- * sched_clock(). This avoids non-bootable kernels when
- * printk_clock is enabled.
- */
-unsigned long long printk_clock(void)
-{
- return (unsigned long long)(jiffies - INITIAL_JIFFIES) *
- (1000000000 / HZ);
-}
-
static unsigned long next_rtc_update;
/*
Index: linux/arch/ia64/kernel/time.c
===================================================================
--- linux.orig/arch/ia64/kernel/time.c
+++ linux/arch/ia64/kernel/time.c
@@ -344,33 +344,6 @@ udelay (unsigned long usecs)
}
EXPORT_SYMBOL(udelay);
-static unsigned long long ia64_itc_printk_clock(void)
-{
- if (ia64_get_kr(IA64_KR_PER_CPU_DATA))
- return sched_clock();
- return 0;
-}
-
-static unsigned long long ia64_default_printk_clock(void)
-{
- return (unsigned long long)(jiffies_64 - INITIAL_JIFFIES) *
- (1000000000/HZ);
-}
-
-unsigned long long (*ia64_printk_clock)(void) = &ia64_default_printk_clock;
-
-unsigned long long printk_clock(void)
-{
- return ia64_printk_clock();
-}
-
-void __init
-ia64_setup_printk_clock(void)
-{
- if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT))
- ia64_printk_clock = ia64_itc_printk_clock;
-}
-
/* IA64 doesn't cache the timezone */
void update_vsyscall_tz(void)
{
Index: linux/arch/x86/kernel/process_32.c
===================================================================
--- linux.orig/arch/x86/kernel/process_32.c
+++ linux/arch/x86/kernel/process_32.c
@@ -113,10 +113,19 @@ void default_idle(void)
smp_mb();
local_irq_disable();
- if (!need_resched())
+ if (!need_resched()) {
+ ktime_t t0, t1;
+ u64 t0n, t1n;
+
+ t0 = ktime_get();
+ t0n = ktime_to_ns(t0);
safe_halt(); /* enables interrupts racelessly */
- else
- local_irq_enable();
+ local_irq_disable();
+ t1 = ktime_get();
+ t1n = ktime_to_ns(t1);
+ sched_clock_idle_wakeup_event(t1n - t0n);
+ }
+ local_irq_enable();
current_thread_info()->status |= TS_POLLING;
} else {
/* loop is done by the caller */
Index: linux/arch/x86/kernel/tsc_32.c
===================================================================
--- linux.orig/arch/x86/kernel/tsc_32.c
+++ linux/arch/x86/kernel/tsc_32.c
@@ -5,6 +5,7 @@
#include <linux/jiffies.h>
#include <linux/init.h>
#include <linux/dmi.h>
+#include <linux/percpu.h>
#include <asm/delay.h>
#include <asm/tsc.h>
@@ -78,15 +79,35 @@ EXPORT_SYMBOL_GPL(check_tsc_unstable);
* cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
* ([email protected])
*
+ * ns += offset to avoid sched_clock jumps with cpufreq
+ *
* [email protected] "math is hard, lets go shopping!"
*/
-unsigned long cyc2ns_scale __read_mostly;
-#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
+DEFINE_PER_CPU(unsigned long, cyc2ns);
-static inline void set_cyc2ns_scale(unsigned long cpu_khz)
+static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
{
- cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
+ unsigned long flags, prev_scale, *scale;
+ unsigned long long tsc_now, ns_now;
+
+ local_irq_save(flags);
+ sched_clock_idle_sleep_event();
+
+ scale = &per_cpu(cyc2ns, cpu);
+
+ rdtscll(tsc_now);
+ ns_now = __cycles_2_ns(tsc_now);
+
+ prev_scale = *scale;
+ if (cpu_khz)
+ *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
+
+ /*
+ * Start smoothly with the new frequency:
+ */
+ sched_clock_idle_wakeup_event(0);
+ local_irq_restore(flags);
}
/*
@@ -239,7 +260,9 @@ time_cpufreq_notifier(struct notifier_bl
ref_freq, freq->new);
if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
tsc_khz = cpu_khz;
- set_cyc2ns_scale(cpu_khz);
+ preempt_disable();
+ set_cyc2ns_scale(cpu_khz, smp_processor_id());
+ preempt_enable();
/*
* TSC based sched_clock turns
* to junk w/ cpufreq
@@ -367,6 +390,8 @@ static inline void check_geode_tsc_relia
void __init tsc_init(void)
{
+ int cpu;
+
if (!cpu_has_tsc || tsc_disable)
goto out_no_tsc;
@@ -380,7 +405,15 @@ void __init tsc_init(void)
(unsigned long)cpu_khz / 1000,
(unsigned long)cpu_khz % 1000);
- set_cyc2ns_scale(cpu_khz);
+ /*
+ * Secondary CPUs do not run through tsc_init(), so set up
+ * all the scale factors for all CPUs, assuming the same
+ * speed as the bootup CPU. (cpufreq notifiers will fix this
+ * up if their speed diverges)
+ */
+ for_each_possible_cpu(cpu)
+ set_cyc2ns_scale(cpu_khz, cpu);
+
use_tsc_delay();
/* Check and install the TSC clocksource */
Index: linux/arch/x86/kernel/tsc_64.c
===================================================================
--- linux.orig/arch/x86/kernel/tsc_64.c
+++ linux/arch/x86/kernel/tsc_64.c
@@ -10,6 +10,7 @@
#include <asm/hpet.h>
#include <asm/timex.h>
+#include <asm/timer.h>
static int notsc __initdata = 0;
@@ -18,16 +19,50 @@ EXPORT_SYMBOL(cpu_khz);
unsigned int tsc_khz;
EXPORT_SYMBOL(tsc_khz);
-static unsigned int cyc2ns_scale __read_mostly;
+/* Accelerators for sched_clock()
+ * convert from cycles(64bits) => nanoseconds (64bits)
+ * basic equation:
+ * ns = cycles / (freq / ns_per_sec)
+ * ns = cycles * (ns_per_sec / freq)
+ * ns = cycles * (10^9 / (cpu_khz * 10^3))
+ * ns = cycles * (10^6 / cpu_khz)
+ *
+ * Then we use scaling math (suggested by [email protected]) to get:
+ * ns = cycles * (10^6 * SC / cpu_khz) / SC
+ * ns = cycles * cyc2ns_scale / SC
+ *
+ * And since SC is a constant power of two, we can convert the div
+ * into a shift.
+ *
+ * We can use khz divisor instead of mhz to keep a better precision, since
+ * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
+ * ([email protected])
+ *
+ * ns += offset to avoid sched_clock jumps with cpufreq
+ *
+ * [email protected] "math is hard, lets go shopping!"
+ */
+DEFINE_PER_CPU(unsigned long, cyc2ns);
-static inline void set_cyc2ns_scale(unsigned long khz)
+static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
{
- cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / khz;
-}
+ unsigned long flags, prev_scale, *scale;
+ unsigned long long tsc_now, ns_now;
-static unsigned long long cycles_2_ns(unsigned long long cyc)
-{
- return (cyc * cyc2ns_scale) >> NS_SCALE;
+ local_irq_save(flags);
+ sched_clock_idle_sleep_event();
+
+ scale = &per_cpu(cyc2ns, cpu);
+
+ rdtscll(tsc_now);
+ ns_now = __cycles_2_ns(tsc_now);
+
+ prev_scale = *scale;
+ if (cpu_khz)
+ *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
+
+ sched_clock_idle_wakeup_event(0);
+ local_irq_restore(flags);
}
unsigned long long sched_clock(void)
@@ -100,7 +135,9 @@ static int time_cpufreq_notifier(struct
mark_tsc_unstable("cpufreq changes");
}
- set_cyc2ns_scale(tsc_khz_ref);
+ preempt_disable();
+ set_cyc2ns_scale(tsc_khz_ref, smp_processor_id());
+ preempt_enable();
return 0;
}
@@ -151,7 +188,7 @@ static unsigned long __init tsc_read_ref
void __init tsc_calibrate(void)
{
unsigned long flags, tsc1, tsc2, tr1, tr2, pm1, pm2, hpet1, hpet2;
- int hpet = is_hpet_enabled();
+ int hpet = is_hpet_enabled(), cpu;
local_irq_save(flags);
@@ -206,7 +243,9 @@ void __init tsc_calibrate(void)
}
tsc_khz = tsc2 / tsc1;
- set_cyc2ns_scale(tsc_khz);
+
+ for_each_possible_cpu(cpu)
+ set_cyc2ns_scale(tsc_khz, cpu);
}
/*
Index: linux/drivers/acpi/processor_idle.c
===================================================================
--- linux.orig/drivers/acpi/processor_idle.c
+++ linux/drivers/acpi/processor_idle.c
@@ -531,6 +531,11 @@ static void acpi_processor_idle(void)
case ACPI_STATE_C3:
/*
+ * Must be done before busmaster disable as we might
+ * need to access HPET !
+ */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ /*
* disable bus master
* bm_check implies we need ARB_DIS
* !bm_check implies we need cache flush
@@ -557,7 +562,6 @@ static void acpi_processor_idle(void)
/* Get start time (ticks) */
t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
/* Invoke C3 */
- acpi_state_timer_broadcast(pr, cx, 1);
/* Tell the scheduler that we are going deep-idle: */
sched_clock_idle_sleep_event();
acpi_cstate_enter(cx);
@@ -1401,9 +1405,6 @@ static int acpi_idle_enter_simple(struct
if (acpi_idle_suspend)
return(acpi_idle_enter_c1(dev, state));
- if (pr->flags.bm_check)
- acpi_idle_update_bm_rld(pr, cx);
-
local_irq_disable();
current_thread_info()->status &= ~TS_POLLING;
/*
@@ -1418,13 +1419,21 @@ static int acpi_idle_enter_simple(struct
return 0;
}
+ /*
+ * Must be done before busmaster disable as we might need to
+ * access HPET !
+ */
+ acpi_state_timer_broadcast(pr, cx, 1);
+
+ if (pr->flags.bm_check)
+ acpi_idle_update_bm_rld(pr, cx);
+
if (cx->type == ACPI_STATE_C3)
ACPI_FLUSH_CPU_CACHE();
t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
/* Tell the scheduler that we are going deep-idle: */
sched_clock_idle_sleep_event();
- acpi_state_timer_broadcast(pr, cx, 1);
acpi_idle_do_entry(cx);
t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
Index: linux/include/asm-x86/timer.h
===================================================================
--- linux.orig/include/asm-x86/timer.h
+++ linux/include/asm-x86/timer.h
@@ -2,6 +2,7 @@
#define _ASMi386_TIMER_H
#include <linux/init.h>
#include <linux/pm.h>
+#include <linux/percpu.h>
#define TICK_SIZE (tick_nsec / 1000)
@@ -16,7 +17,7 @@ extern int recalibrate_cpu_khz(void);
#define calculate_cpu_khz() native_calculate_cpu_khz()
#endif
-/* Accellerators for sched_clock()
+/* Accelerators for sched_clock()
* convert from cycles(64bits) => nanoseconds (64bits)
* basic equation:
* ns = cycles / (freq / ns_per_sec)
@@ -31,20 +32,32 @@ extern int recalibrate_cpu_khz(void);
* And since SC is a constant power of two, we can convert the div
* into a shift.
*
- * We can use khz divisor instead of mhz to keep a better percision, since
+ * We can use khz divisor instead of mhz to keep a better precision, since
* cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
* ([email protected])
*
* [email protected] "math is hard, lets go shopping!"
*/
-extern unsigned long cyc2ns_scale __read_mostly;
+
+DECLARE_PER_CPU(unsigned long, cyc2ns);
#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
-static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+static inline unsigned long long __cycles_2_ns(unsigned long long cyc)
{
- return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
+ return cyc * per_cpu(cyc2ns, smp_processor_id()) >> CYC2NS_SCALE_FACTOR;
}
+static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+{
+ unsigned long long ns;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ ns = __cycles_2_ns(cyc);
+ local_irq_restore(flags);
+
+ return ns;
+}
#endif
Index: linux/kernel/hrtimer.c
===================================================================
--- linux.orig/kernel/hrtimer.c
+++ linux/kernel/hrtimer.c
@@ -850,6 +850,14 @@ hrtimer_start(struct hrtimer *timer, kti
#ifdef CONFIG_TIME_LOW_RES
tim = ktime_add(tim, base->resolution);
#endif
+ /*
+ * Careful here: User space might have asked for a
+ * very long sleep, so the add above might result in a
+ * negative number, which enqueues the timer in front
+ * of the queue.
+ */
+ if (tim.tv64 < 0)
+ tim.tv64 = KTIME_MAX;
}
timer->expires = tim;
Index: linux/kernel/lockdep.c
===================================================================
--- linux.orig/kernel/lockdep.c
+++ linux/kernel/lockdep.c
@@ -2654,10 +2654,15 @@ static void check_flags(unsigned long fl
if (!debug_locks)
return;
- if (irqs_disabled_flags(flags))
- DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled);
- else
- DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled);
+ if (irqs_disabled_flags(flags)) {
+ if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
+ printk("possible reason: unannotated irqs-off.\n");
+ }
+ } else {
+ if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
+ printk("possible reason: unannotated irqs-on.\n");
+ }
+ }
/*
* We dont accurately track softirq state in e.g.
Index: linux/kernel/printk.c
===================================================================
--- linux.orig/kernel/printk.c
+++ linux/kernel/printk.c
@@ -573,11 +573,6 @@ static int __init printk_time_setup(char
__setup("time", printk_time_setup);
-__attribute__((weak)) unsigned long long printk_clock(void)
-{
- return sched_clock();
-}
-
/* Check if we have any console registered that can be called early in boot. */
static int have_callable_console(void)
{
@@ -628,30 +623,57 @@ asmlinkage int printk(const char *fmt, .
/* cpu currently holding logbuf_lock */
static volatile unsigned int printk_cpu = UINT_MAX;
+const char printk_recursion_bug_msg [] =
+ KERN_CRIT "BUG: recent printk recursion!\n";
+static int printk_recursion_bug;
+
asmlinkage int vprintk(const char *fmt, va_list args)
{
+ static int log_level_unknown = 1;
+ static char printk_buf[1024];
+
unsigned long flags;
- int printed_len;
+ int printed_len = 0;
+ int this_cpu;
char *p;
- static char printk_buf[1024];
- static int log_level_unknown = 1;
boot_delay_msec();
preempt_disable();
- if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
- /* If a crash is occurring during printk() on this CPU,
- * make sure we can't deadlock */
- zap_locks();
-
/* This stops the holder of console_sem just where we want him */
raw_local_irq_save(flags);
+ this_cpu = smp_processor_id();
+
+ /*
+ * Ouch, printk recursed into itself!
+ */
+ if (unlikely(printk_cpu == this_cpu)) {
+ /*
+ * If a crash is occurring during printk() on this CPU,
+ * then try to get the crash message out but make sure
+ * we can't deadlock. Otherwise just return to avoid the
+ * recursion and return - but flag the recursion so that
+ * it can be printed at the next appropriate moment:
+ */
+ if (!oops_in_progress) {
+ printk_recursion_bug = 1;
+ goto out_restore_irqs;
+ }
+ zap_locks();
+ }
+
lockdep_off();
spin_lock(&logbuf_lock);
- printk_cpu = smp_processor_id();
+ printk_cpu = this_cpu;
+ if (printk_recursion_bug) {
+ printk_recursion_bug = 0;
+ strcpy(printk_buf, printk_recursion_bug_msg);
+ printed_len = sizeof(printk_recursion_bug_msg);
+ }
/* Emit the output into the temporary buffer */
- printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args);
+ printed_len += vscnprintf(printk_buf + printed_len,
+ sizeof(printk_buf), fmt, args);
/*
* Copy the output into log_buf. If the caller didn't provide
@@ -680,7 +702,11 @@ asmlinkage int vprintk(const char *fmt,
loglev_char = default_message_loglevel
+ '0';
}
- t = printk_clock();
+ if (panic_timeout) {
+ panic_timeout = 0;
+ printk("recurse!\n");
+ }
+ t = cpu_clock(printk_cpu);
nanosec_rem = do_div(t, 1000000000);
tlen = sprintf(tbuf,
"<%c>[%5lu.%06lu] ",
@@ -744,6 +770,7 @@ asmlinkage int vprintk(const char *fmt,
printk_cpu = UINT_MAX;
spin_unlock(&logbuf_lock);
lockdep_on();
+out_restore_irqs:
raw_local_irq_restore(flags);
}
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -488,7 +488,12 @@ unsigned long long cpu_clock(int cpu)
local_irq_save(flags);
rq = cpu_rq(cpu);
- update_rq_clock(rq);
+ /*
+ * Only call sched_clock() if the scheduler has already been
+ * initialized (some code might call cpu_clock() very early):
+ */
+ if (rq->idle)
+ update_rq_clock(rq);
now = rq->clock;
local_irq_restore(flags);
Index: linux/kernel/sched_fair.c
===================================================================
--- linux.orig/kernel/sched_fair.c
+++ linux/kernel/sched_fair.c
@@ -511,8 +511,7 @@ place_entity(struct cfs_rq *cfs_rq, stru
if (!initial) {
/* sleeps upto a single latency don't count. */
- if (sched_feat(NEW_FAIR_SLEEPERS) && entity_is_task(se) &&
- task_of(se)->policy != SCHED_BATCH)
+ if (sched_feat(NEW_FAIR_SLEEPERS) && entity_is_task(se))
vruntime -= sysctl_sched_latency;
/* ensure we never gain time by being placed backwards. */
Index: linux/kernel/time/clockevents.c
===================================================================
--- linux.orig/kernel/time/clockevents.c
+++ linux/kernel/time/clockevents.c
@@ -78,6 +78,11 @@ int clockevents_program_event(struct clo
unsigned long long clc;
int64_t delta;
+ if (unlikely(expires.tv64 < 0)) {
+ WARN_ON_ONCE(1);
+ return -ETIME;
+ }
+
delta = ktime_to_ns(ktime_sub(expires, now));
if (delta <= 0)
On Fri, 2007-12-07 at 20:59 +0100, Ingo Molnar wrote:
> * Fernando Lopez-Lezcano <[email protected]> wrote:
>
> > > Nope, it doesn't still getting "delay" and "xrun" messages galore.
> >
> > Attached: configuration and dmesg output booting with idle=poll,
> > reconfirmed that that makes the delay and xrun messages go away.
>
> could you try the rolled up patch of various fixlets, ontop of current
> -git? (it might even apply to -rc4) It includes some more stuff beyond
> the ones in the pull request. (still being tested/reviewed)
I'll try but it will take me a while to figure git and do a package
build of it...
-- Fernando
* Fernando Lopez-Lezcano <[email protected]> wrote:
> On Fri, 2007-12-07 at 20:59 +0100, Ingo Molnar wrote:
> > * Fernando Lopez-Lezcano <[email protected]> wrote:
> >
> > > > Nope, it doesn't still getting "delay" and "xrun" messages galore.
> > >
> > > Attached: configuration and dmesg output booting with idle=poll,
> > > reconfirmed that that makes the delay and xrun messages go away.
> >
> > could you try the rolled up patch of various fixlets, ontop of
> > current -git? (it might even apply to -rc4) It includes some more
> > stuff beyond the ones in the pull request. (still being
> > tested/reviewed)
>
> I'll try but it will take me a while to figure git and do a package
> build of it...
if you want to try a vanilla kernel package then pick up the kernel
package from Fedora rawhide - this fixlet should show up there within a
couple of days, Dave Jones is doing a really nice job of keeping up with
latest -git. (and the Fedora kernel has hrtimers and dynticks enabled.)
Ingo
Hi!
> @@ -78,15 +79,35 @@ EXPORT_SYMBOL_GPL(check_tsc_unstable);
> * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
> * ([email protected])
> *
> + * ns += offset to avoid sched_clock jumps with cpufreq
> + *
> * [email protected] "math is hard, lets go shopping!"
> */
Did john add the 'ns+=' or do comments need reorder?
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
On Dec 9, 2007 7:01 PM, Pavel Machek <[email protected]> wrote:
> > + * ns += offset to avoid sched_clock jumps with cpufreq
> > + *
> > * [email protected] "math is hard, lets go shopping!"
> > */
>
> Did john add the 'ns+=' or do comments need reorder?
I added it, but I think it needs to be removed as now the offset is maintained
by the scheduler in __update_rq_clock().
Thanks.
--
Guillaume
* Guillaume Chazarain <[email protected]> wrote:
> On Dec 9, 2007 7:01 PM, Pavel Machek <[email protected]> wrote:
> > > + * ns += offset to avoid sched_clock jumps with cpufreq
> > > + *
> > > * [email protected] "math is hard, lets go shopping!"
> > > */
> >
> > Did john add the 'ns+=' or do comments need reorder?
>
> I added it, but I think it needs to be removed as now the offset is
> maintained by the scheduler in __update_rq_clock().
yeah, and it's already removed in latest x86.git.
Ingo
On Sat, 2007-12-08 at 10:17 +0100, Ingo Molnar wrote:
> * Fernando Lopez-Lezcano <[email protected]> wrote:
>
> > On Fri, 2007-12-07 at 20:59 +0100, Ingo Molnar wrote:
> > > * Fernando Lopez-Lezcano <[email protected]> wrote:
> > >
> > > > > Nope, it doesn't still getting "delay" and "xrun" messages galore.
> > > >
> > > > Attached: configuration and dmesg output booting with idle=poll,
> > > > reconfirmed that that makes the delay and xrun messages go away.
> > >
> > > could you try the rolled up patch of various fixlets, ontop of
> > > current -git? (it might even apply to -rc4) It includes some more
> > > stuff beyond the ones in the pull request. (still being
> > > tested/reviewed)
> >
> > I'll try but it will take me a while to figure git and do a package
> > build of it...
>
> if you want to try a vanilla kernel package then pick up the kernel
> package from Fedora rawhide - this fixlet should show up there within a
> couple of days, Dave Jones is doing a really nice job of keeping up with
> latest -git. (and the Fedora kernel has hrtimers and dynticks enabled.)
Hi Ingo... back to testing.
History:
2.6.23.x + rt has not been very usable for audio applications.
2.6.24-rt1: same so far.
Why: Jack keeps printing "delayed..." messages and has xruns which means
that somehow the timing is delayed more than what jack would think
reasonable. As in the case with an old timing bug, the problem
dissapears when booting the kernel with idle=poll. Other users of Planet
CCRMA are able to replicate the behavior, which goes away with idle=poll
or booting the machine with only one core. As a workaround I have been
packaging 2.6.22.x but now I'm not able to use that as the old rt14
patch, suitably tweaked results in a non working kernel.
So it looks like, again, timing is getting skewed when the jack process
jumps between cpus and thus jack sees timing jumps that are just not
happenning.
This is with a build based on 2.6.24 using as a base the latest Fedora
rawhide source package plus 2.6.24-rt1.
-- Fernando
On Sat, 2008-01-26 at 17:59 -0800, Fernando Lopez-Lezcano wrote:
> Hi Ingo... back to testing.
> History:
>
> 2.6.23.x + rt has not been very usable for audio applications.
> 2.6.24-rt1: same so far.
>
> Why: Jack keeps printing "delayed..." messages and has xruns which means
> that somehow the timing is delayed more than what jack would think
> reasonable. As in the case with an old timing bug, the problem
> dissapears when booting the kernel with idle=poll. Other users of Planet
> CCRMA are able to replicate the behavior, which goes away with idle=poll
> or booting the machine with only one core. As a workaround I have been
> packaging 2.6.22.x but now I'm not able to use that as the old rt14
> patch, suitably tweaked results in a non working kernel.
>
> So it looks like, again, timing is getting skewed when the jack process
> jumps between cpus and thus jack sees timing jumps that are just not
> happenning.
>
> This is with a build based on 2.6.24 using as a base the latest Fedora
> rawhide source package plus 2.6.24-rt1.
Do you have a simple testcase? (one which doesn't entail installing
ccrma and becoming an audiophile)
-Mike
On Sun, 2008-01-27 at 05:46 +0100, Mike Galbraith wrote:
> On Sat, 2008-01-26 at 17:59 -0800, Fernando Lopez-Lezcano wrote:
>
> > Hi Ingo... back to testing.
> > History:
> >
> > 2.6.23.x + rt has not been very usable for audio applications.
> > 2.6.24-rt1: same so far.
> >
> > Why: Jack keeps printing "delayed..." messages and has xruns which means
> > that somehow the timing is delayed more than what jack would think
> > reasonable. As in the case with an old timing bug, the problem
> > dissapears when booting the kernel with idle=poll. Other users of Planet
> > CCRMA are able to replicate the behavior, which goes away with idle=poll
> > or booting the machine with only one core. As a workaround I have been
> > packaging 2.6.22.x but now I'm not able to use that as the old rt14
> > patch, suitably tweaked results in a non working kernel.
> >
> > So it looks like, again, timing is getting skewed when the jack process
> > jumps between cpus and thus jack sees timing jumps that are just not
> > happenning.
> >
> > This is with a build based on 2.6.24 using as a base the latest Fedora
> > rawhide source package plus 2.6.24-rt1.
>
> Do you have a simple testcase? (one which doesn't entail installing
> ccrma and becoming an audiophile)
No, I don't at this point.
I'll see if I can cook something simple today... (naively thinking that
some short C code could test for the clock being actually monotonic
across cpus).
-- Fernando
On Mon, 2008-01-28 at 10:26 -0800, Fernando Lopez-Lezcano wrote:
> On Sun, 2008-01-27 at 05:46 +0100, Mike Galbraith wrote:
> > On Sat, 2008-01-26 at 17:59 -0800, Fernando Lopez-Lezcano wrote:
> >
> > > Hi Ingo... back to testing.
> > > History:
> > >
> > > 2.6.23.x + rt has not been very usable for audio applications.
> > > 2.6.24-rt1: same so far.
> > >
> > > Why: Jack keeps printing "delayed..." messages and has xruns which means
> > > that somehow the timing is delayed more than what jack would think
> > > reasonable. As in the case with an old timing bug, the problem
> > > dissapears when booting the kernel with idle=poll. Other users of Planet
> > > CCRMA are able to replicate the behavior, which goes away with idle=poll
> > > or booting the machine with only one core. As a workaround I have been
> > > packaging 2.6.22.x but now I'm not able to use that as the old rt14
> > > patch, suitably tweaked results in a non working kernel.
> > >
> > > So it looks like, again, timing is getting skewed when the jack process
> > > jumps between cpus and thus jack sees timing jumps that are just not
> > > happenning.
> > >
> > > This is with a build based on 2.6.24 using as a base the latest Fedora
> > > rawhide source package plus 2.6.24-rt1.
> >
> > Do you have a simple testcase? (one which doesn't entail installing
> > ccrma and becoming an audiophile)
>
> No, I don't at this point.
> I'll see if I can cook something simple today... (naively thinking that
> some short C code could test for the clock being actually monotonic
> across cpus).
Sorry, no luck so far in writing something simple that will fail. I
tried testing for the results from repeated calls to clock_gettime (what
jack uses for timing by default) to actually be monotonic, while a
script uses taskset to force a cpu switch and of course got no errors.
2.6.24-rt1 with idle=poll works fine, without it I get multiple problems
with the jack internal timing, or least that is what it seems to me from
the symptoms.
-- Fernando