Wrapper to use the lower level clock sources available on the systems. Fall-back on jiffies or'd with a logical clock for architectures lacking CPU timestamp counters. Fall-back on a mixed TSC-logical clock on architectures lacking synchronized TSC on SMP. A generic fallback based on a logical clock and the timer interrupt is available. generic - Uses jiffies or'd with a logical clock extended to 64 bits by ltt-timestamp.c. i386 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical clock. mips - Uses TSC extended atomically from 32 to 64 bits by ltt-heartbeat.c. powerpc - Uses TSC or generic ltt clock. x86_64 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical clock Signed-off-by: Mathieu Desnoyers CC: Ralf Baechle CC: benh@kernel.crashing.org CC: paulus@samba.org CC: David Miller CC: Linus Torvalds CC: Andrew Morton CC: Ingo Molnar CC: Peter Zijlstra CC: Thomas Gleixner CC: Steven Rostedt CC: linux-arch@vger.kernel.org --- include/asm-generic/ltt.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/ltt.h | 27 +++++++++++++++++++++++ kernel/timer.c | 2 + 3 files changed, 82 insertions(+) Index: linux-2.6-lttng/kernel/timer.c =================================================================== --- linux-2.6-lttng.orig/kernel/timer.c 2008-09-16 14:50:15.000000000 -0400 +++ linux-2.6-lttng/kernel/timer.c 2008-09-16 14:59:17.000000000 -0400 @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -1066,6 +1067,7 @@ void do_timer(unsigned long ticks) { jiffies_64 += ticks; update_times(ticks); + ltt_add_timestamp(ticks); } #ifdef __ARCH_WANT_SYS_ALARM Index: linux-2.6-lttng/include/linux/ltt.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6-lttng/include/linux/ltt.h 2008-09-16 14:58:47.000000000 -0400 @@ -0,0 +1,27 @@ +#ifndef _LINUX_LTT_H +#define _LINUX_LTT_H + +/* + * Generic LTT clock. + * + * Chooses between an architecture specific clock or an atomic logical clock. + * + * Copyright (C) 2007 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) + */ + +#ifdef CONFIG_LTT_TIMESTAMP +#ifdef CONFIG_HAVE_LTT_CLOCK +#include +#else +#include + +#define ltt_get_timestamp32 ltt_get_timestamp32_generic +#define ltt_get_timestamp64 ltt_get_timestamp64_generic +#define ltt_add_timestamp ltt_add_timestamp_generic +#define ltt_frequency ltt_frequency_generic +#define ltt_freq_scale ltt_freq_scale_generic +#endif /* CONFIG_HAVE_LTT_CLOCK */ +#else +#define ltt_add_timestamp(ticks) +#endif /* CONFIG_LTT_TIMESTAMP */ +#endif /* _LINUX_LTT_H */ Index: linux-2.6-lttng/include/asm-generic/ltt.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6-lttng/include/asm-generic/ltt.h 2008-09-16 14:58:47.000000000 -0400 @@ -0,0 +1,53 @@ +#ifndef _ASM_GENERIC_LTT_H +#define _ASM_GENERIC_LTT_H + +/* + * linux/include/asm-generic/ltt.h + * + * Copyright (C) 2007 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) + * + * Generic definitions for LTT + * Architectures without TSC + */ + +#include /* For HZ */ +#include + +#define LTT_GENERIC_CLOCK_SHIFT 13 + +u64 ltt_read_synthetic_tsc(void); + +extern atomic_t lttng_generic_clock; + +static inline u32 ltt_get_timestamp32_generic(void) +{ + return atomic_add_return(1, <tng_generic_clock); +} + +static inline u64 ltt_get_timestamp64_generic(void) +{ + return ltt_read_synthetic_tsc(); +} + +static inline void ltt_add_timestamp_generic(unsigned long ticks) +{ + int old_clock, new_clock; + + do { + old_clock = atomic_read(<tng_generic_clock); + new_clock = (old_clock + (ticks << LTT_GENERIC_CLOCK_SHIFT)) + & (~((1 << LTT_GENERIC_CLOCK_SHIFT) - 1)); + } while (atomic_cmpxchg(<tng_generic_clock, old_clock, new_clock) + != old_clock); +} + +static inline unsigned int ltt_frequency_generic(void) +{ + return HZ << LTT_GENERIC_CLOCK_SHIFT; +} + +static inline u32 ltt_freq_scale_generic(void) +{ + return 1; +} +#endif /* _ASM_GENERIC_LTT_H */ -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/