Messages in this thread Patch in this message | | | Date | Tue, 03 Jan 2006 23:23:59 +0000 | From | Shailabh Nagar <> | Subject | [Patch 1/6] Delay accounting: timespec diff |
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nstimestamp_diff.patch
Add kernel utility function for measuring the interval (diff) between two timespec values, adjusting for overflow
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
include/linux/time.h | 15 +++++++++++++++ 1 files changed, 15 insertions(+)
Index: linux-2.6.15-rc7/include/linux/time.h =================================================================== --- linux-2.6.15-rc7.orig/include/linux/time.h +++ linux-2.6.15-rc7/include/linux/time.h @@ -114,6 +114,21 @@ set_normalized_timespec (struct timespec ts->tv_nsec = nsec; }
+/* + * timespec_diff_ns - Return difference of two timestamps in nanoseconds + * In the rare case of @end being earlier than @start, return zero + */ +static inline unsigned long long +timespec_diff_ns(struct timespec *start, struct timespec *end) +{ + long long ret; + + ret = end->tv_sec*(1000000000) + end->tv_nsec; + ret -= start->tv_sec*(1000000000) + start->tv_nsec; + if (ret < 0) + return 0; + return ret; +} #endif /* __KERNEL__ */
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