9dbafa5368
The least significant bit of the TOD clock value returned by get_clock is the 4096th part of a microsecond. To get to nanoseconds the value needs to be divided by 4096 and multiplied with 1000. The current method multiplies first and then shifts the value to make the result as precise as possible. The disadvantage is that the multiplication with 1000 will overflow shortly after 52 days. sched_clock is used by the scheduler for time stamp deltas, if an overflow occurs between two time stamps the scheduler will get confused. With the patch the problem occurs only after approx. one year, so the chance to run into this overflow is extremly low. Signed-off-by: Jan Glauber <jan.glauber@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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