From 31089c13bcb18d2cd2a3ddfbe3a28666346f237e Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 14 Aug 2009 15:47:18 +0200 Subject: timekeeping: Introduce timekeeping_leap_insert Move the adjustment of xtime, wall_to_monotonic and the update of the vsyscall variables to the timekeeping code. Signed-off-by: John Stultz Signed-off-by: Martin Schwidefsky LKML-Reference: <20090814134807.609730216@de.ibm.com> Signed-off-by: Thomas Gleixner --- include/linux/time.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/time.h') diff --git a/include/linux/time.h b/include/linux/time.h index ea16c1a01d51..e7c844558884 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -147,6 +147,7 @@ extern struct timespec timespec_trunc(struct timespec t, unsigned gran); extern int timekeeping_valid_for_hres(void); extern void update_wall_time(void); extern void update_xtime_cache(u64 nsec); +extern void timekeeping_leap_insert(int leapsecond); struct tms; extern void do_sys_times(struct tms *); -- cgit v1.2.2 From d4f587c67fc39e0030ddd718675e252e208da4d7 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Fri, 14 Aug 2009 15:47:31 +0200 Subject: timekeeping: Increase granularity of read_persistent_clock() The persistent clock of some architectures (e.g. s390) have a better granularity than seconds. To reduce the delta between the host clock and the guest clock in a virtualized system change the read_persistent_clock function to return a struct timespec. Signed-off-by: Martin Schwidefsky Cc: Ingo Molnar Acked-by: John Stultz Cc: Daniel Walker LKML-Reference: <20090814134811.013873340@de.ibm.com> Signed-off-by: Thomas Gleixner --- include/linux/time.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/time.h') diff --git a/include/linux/time.h b/include/linux/time.h index e7c844558884..53a3216f0d1b 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -101,7 +101,7 @@ extern struct timespec xtime; extern struct timespec wall_to_monotonic; extern seqlock_t xtime_lock; -extern unsigned long read_persistent_clock(void); +extern void read_persistent_clock(struct timespec *ts); extern int update_persistent_clock(struct timespec now); extern int no_sync_cmos_clock __read_mostly; void timekeeping_init(void); -- cgit v1.2.2 From 23970e389e9cee43c4b41023935e1417271708b2 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Fri, 14 Aug 2009 15:47:32 +0200 Subject: timekeeping: Introduce read_boot_clock Add the new function read_boot_clock to get the exact time the system has been started. For architectures without support for exact boot time a new weak function is added that returns 0. Use the exact boot time to initialize wall_to_monotonic, or xtime if the read_boot_clock returned 0. Signed-off-by: Martin Schwidefsky Cc: Ingo Molnar Acked-by: John Stultz Cc: Daniel Walker LKML-Reference: <20090814134811.296703241@de.ibm.com> Signed-off-by: Thomas Gleixner --- include/linux/time.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/time.h') diff --git a/include/linux/time.h b/include/linux/time.h index 53a3216f0d1b..f505988398e6 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -102,6 +102,7 @@ extern struct timespec wall_to_monotonic; extern seqlock_t xtime_lock; extern void read_persistent_clock(struct timespec *ts); +extern void read_boot_clock(struct timespec *ts); extern int update_persistent_clock(struct timespec now); extern int no_sync_cmos_clock __read_mostly; void timekeeping_init(void); -- cgit v1.2.2 From da15cfdae03351c689736f8d142618592e3cebc3 Mon Sep 17 00:00:00 2001 From: john stultz Date: Wed, 19 Aug 2009 19:13:34 -0700 Subject: time: Introduce CLOCK_REALTIME_COARSE After talking with some application writers who want very fast, but not fine-grained timestamps, I decided to try to implement new clock_ids to clock_gettime(): CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE which returns the time at the last tick. This is very fast as we don't have to access any hardware (which can be very painful if you're using something like the acpi_pm clocksource), and we can even use the vdso clock_gettime() method to avoid the syscall. The only trade off is you only get low-res tick grained time resolution. This isn't a new idea, I know Ingo has a patch in the -rt tree that made the vsyscall gettimeofday() return coarse grained time when the vsyscall64 sysctrl was set to 2. However this affects all applications on a system. With this method, applications can choose the proper speed/granularity trade-off for themselves. Signed-off-by: John Stultz Cc: Andi Kleen Cc: nikolag@ca.ibm.com Cc: Darren Hart Cc: arjan@infradead.org Cc: jonathan@jonmasters.org LKML-Reference: <1250734414.6897.5.camel@localhost.localdomain> Signed-off-by: Thomas Gleixner --- include/linux/time.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/time.h') diff --git a/include/linux/time.h b/include/linux/time.h index f505988398e6..256232f7e5e6 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -110,6 +110,8 @@ extern int timekeeping_suspended; unsigned long get_seconds(void); struct timespec current_kernel_time(void); +struct timespec __current_kernel_time(void); /* does not hold xtime_lock */ +struct timespec get_monotonic_coarse(void); #define CURRENT_TIME (current_kernel_time()) #define CURRENT_TIME_SEC ((struct timespec) { get_seconds(), 0 }) @@ -243,6 +245,8 @@ struct itimerval { #define CLOCK_PROCESS_CPUTIME_ID 2 #define CLOCK_THREAD_CPUTIME_ID 3 #define CLOCK_MONOTONIC_RAW 4 +#define CLOCK_REALTIME_COARSE 5 +#define CLOCK_MONOTONIC_COARSE 6 /* * The IDs of various hardware clocks: -- cgit v1.2.2 From 12e09337fe238981cb0c87543306e23775d1a143 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 14 Sep 2009 23:37:40 +0200 Subject: time: Prevent 32 bit overflow with set_normalized_timespec() set_normalized_timespec() nsec argument is of type long. The recent timekeeping changes of ktime_get_ts() feed ts->tv_nsec + tomono.tv_nsec + nsecs to set_normalized_timespec(). On 32 bit machines that sum can be larger than (1 << 31) and therefor result in a negative value which screws up the result completely. Make the nsec argument of set_normalized_timespec() s64 to fix the problem at hand. This also prevents similar problems for future users of set_normalized_timespec(). Signed-off-by: Thomas Gleixner Tested-by: Carsten Emde LKML-Reference: Cc: Martin Schwidefsky Cc: John Stultz --- include/linux/time.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/time.h') diff --git a/include/linux/time.h b/include/linux/time.h index 256232f7e5e6..56787c093345 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -75,7 +75,7 @@ extern unsigned long mktime(const unsigned int year, const unsigned int mon, const unsigned int day, const unsigned int hour, const unsigned int min, const unsigned int sec); -extern void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec); +extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec); extern struct timespec timespec_add_safe(const struct timespec lhs, const struct timespec rhs); -- cgit v1.2.2