From 2eb5f31bc4ea24bb293e82934cfa1cce9573304b Mon Sep 17 00:00:00 2001 From: Anton Ivanov Date: Mon, 2 Nov 2015 16:16:37 +0000 Subject: um: Switch clocksource to hrtimers UML is using an obsolete itimer call for all timers and "polls" for kernel space timer firing in its userspace portion resulting in a long list of bugs and incorrect behaviour(s). It also uses ITIMER_VIRTUAL for its timer which results in the timer being dependent on it running and the cpu load. This patch fixes this by moving to posix high resolution timers firing off CLOCK_MONOTONIC and relaying the timer correctly to the UML userspace. Fixes: - crashes when hosts suspends/resumes - broken userspace timers - effecive ~40Hz instead of what they should be. Note - this modifies skas behavior by no longer setting an itimer per clone(). Timer events are relayed instead. - kernel network packet scheduling disciplines - tcp behaviour especially under load - various timer related corner cases Finally, overall responsiveness of userspace is better. Signed-off-by: Thomas Meyer Signed-off-by: Anton Ivanov [rw: massaged commit message] Signed-off-by: Richard Weinberger --- arch/um/include/shared/timer-internal.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) create mode 100644 arch/um/include/shared/timer-internal.h (limited to 'arch/um/include/shared/timer-internal.h') diff --git a/arch/um/include/shared/timer-internal.h b/arch/um/include/shared/timer-internal.h new file mode 100644 index 000000000000..03e6f217f807 --- /dev/null +++ b/arch/um/include/shared/timer-internal.h @@ -0,0 +1,13 @@ +/* + * Copyright (C) 2012 - 2014 Cisco Systems + * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + * Licensed under the GPL + */ + +#ifndef __TIMER_INTERNAL_H__ +#define __TIMER_INTERNAL_H__ + +#define TIMER_MULTIPLIER 256 +#define TIMER_MIN_DELTA 500 + +#endif -- cgit v1.2.3