linux/kernel/time, branch v2.6.21.6

[PATCH] timer stats: speedups

2007-06-11T18:36:48Z

Make timer-stats have almost zero overhead when enabled in the config but not used. (this way distros can enable it more easily) Also update the documentation about overhead of timer_stats - it was written for the first version which had a global lock and a linear list walk based lookup ;-) Andrew says: And this. Not a bugfix, but trivial and obvious and apparently some distros don't want to enable timer_stats because of the performance issue, but powertop uses timer_stats. Ingo replies: seconded. I have tested this with and without CONFIG_TIMER_STATS, with and without timer_stats collection activated. Signed-off-by: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman

[PATCH] timer statistics: fix race

2007-06-11T18:36:48Z

Fix two races in the timer stats lookup code. One by ensuring that the initialization of a new entry is finished upon insertion of that entry. The other by cleaning up the hash table when the entries array is cleared, so that we don't have any "pre-inserted" entries. Thanks to Eric Dumazet for reminding me of the memory barriers. Signed-off-by: Bjorn Steinbrink Signed-off-by: Ian Kumlien Acked-by: Ingo Molnar Cc: Eric Dumazet Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman

[PATCH] NOHZ: Rate limit the local softirq pending warning output

2007-06-11T18:36:44Z

The warning in the NOHZ code, which triggers when a CPU goes idle with softirqs pending can fill up the logs quite quickly. Rate limit the output until we found the root cause of that problem. Signed-off-by: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman

[PATCH] Ignore bogus ACPI info for offline CPUs

2007-06-11T18:36:43Z

Booting a SMP kernel with maxcpus=1 on a SMP system leads to a hard hang, because ACPI ignores the maxcpus setting and sends timer broadcast info for the offline CPUs. This results in a stuck for ever call to smp_call_function_single() on an offline CPU. Ignore the bogus information and print a kernel error to remind ACPI folks to fix it. Affects 2.6.21 / 2.6.22-rc Signed-off-by: Thomas Gleixner Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman

[PATCH] clocksource: fix resume logic

2007-05-23T21:32:48Z

We need to make sure that the clocksources are resumed, when timekeeping is resumed. The current resume logic does not guarantee this. Add a resume function pointer to the clocksource struct, so clocksource drivers which need to reinitialize the clocksource can provide a resume function. Add a resume function, which calls the maybe available clocksource resume functions and resets the watchdog function, so a stable TSC can be used accross suspend/resume. Signed-off-by: Thomas Gleixner Cc: john stultz Cc: Andi Kleen Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Chris Wright

[PATCH] highres/dyntick: prevent xtime lock contention

2007-05-23T21:32:46Z

While the !highres/!dyntick code assigns the duty of the do_timer() call to one specific CPU, this was dropped in the highres/dyntick part during development. Steven Rostedt discovered the xtime lock contention on highres/dyntick due to several CPUs trying to update jiffies. Add the single CPU assignement back. In the dyntick case this needs to be handled carefully, as the CPU which has the do_timer() duty must drop the assignement and let it be grabbed by another CPU, which is active. Otherwise the do_timer() calls would not happen during the long sleep. Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Cc: Steven Rostedt Acked-by: Mark Lord Signed-off-by: Andrew Morton Signed-off-by: Chris Wright

[PATCH] fix jiffies clocksource inittime

2007-04-05T04:12:47Z

In debugging a problem w/ the -rt tree, I noticed that on systems that mark the tsc as unstable before it is registered, the TSC would still be selected and used for a short period of time. Digging in it looks to be a result of the mix of the clocksource list changes and my clocksource initialization changes. With the -rt tree, using a bad TSC, even for a short period of time can results in a hang at boot. I was not able to reproduce this hang w/ mainline, but I'm not completely certain that someone won't trip on it. This patch resolves the issue by initializing the jiffies clocksource earlier so a bad TSC won't get selected just because nothing else is yet registered. Signed-off-by: John Stultz Acked-by: Thomas Gleixner Cc: Ingo Molnar Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] ntp: avoid time_offset overflows

2007-03-27T16:05:15Z

I've been seeing some odd NTP behavior recently on a few boxes and finally narrowed it down to time_offset overflowing when converted to SHIFT_UPDATE units (which was a side effect from my HZfreeNTP patch). This patch converts time_offset from a long to a s64 which resolves the issue. [tglx@linutronix.de: signedness fixes] Signed-off-by: John Stultz Cc: Roman Zippel Cc: john stultz Cc: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] clockevents: remove bad designed sysfs support for now

2007-03-26T21:07:23Z

The current sysfs support of clockevents does not obey the "only one value per file" rule. The real fix is not 2.6.21 material. Therefor remove the sysfs support for now. Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Acked-by: Greg Kroah-Hartman Signed-off-by: Linus Torvalds

[PATCH] clocksource: Fix thinko in watchdog selection

2007-03-25T21:57:34Z

The watchdog implementation excludes low res / non continuous clocksources from being selected as a watchdog reference unintentionally. Allow using jiffies/PIT as a watchdog reference as long as no better clocksource is available. This is necessary to detect TSC breakage on systems, which have no pmtimer/hpet. The main goal of the initial patch (preventing to switch to highres/nohz when no reliable fallback clocksource is available) is still guaranteed by the checks in clocksource_watchdog(). Signed-off-by: Thomas Gleixner Signed-off-by: Linus Torvalds