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Commit 4b8f573b authored by YOSHIFUJI Hideaki's avatar YOSHIFUJI Hideaki Committed by Linus Torvalds
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[PATCH] TIMERS: add missing compensation for HZ == 250 



Add missing compensation for (HZ == 250) != (1 << SHIFT_HZ) in
second_overflow().

Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 930fc45a

kernel/timer.c

+9 −0
Original line number Diff line number Diff line
@@ -752,6 +752,15 @@ static void second_overflow(void) 
    else

	time_adj += (time_adj >> 2) + (time_adj >> 5);

#endif

#if HZ == 250

    /* Compensate for (HZ==250) != (1 << SHIFT_HZ).

     * Add 1.5625% and 0.78125% to get 255.85938; => only 0.05% error (p. 14)

     */

    if (time_adj < 0)

	time_adj -= (-time_adj >> 6) + (-time_adj >> 7);

    else

	time_adj += (time_adj >> 6) + (time_adj >> 7);

#endif

#if HZ == 1000

    /* Compensate for (HZ==1000) != (1 << SHIFT_HZ).

     * Add 1.5625% and 0.78125% to get 1023.4375; => only 0.05% error (p. 14)