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| author | Stanislaw Gruszka <sgruszka@redhat.com> | 2009-07-29 12:15:29 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-08-03 14:48:36 +0200 |
| commit | a42548a18866e87092db93b771e6c5b060d78401 (patch) | |
| tree | 897acf5794920ec9c6fd7f87af63908d0c1988f9 /arch/s390 | |
| parent | d1e3b6d195770bd422e3229b88edfc154b6a27dd (diff) | |
| download | kernel_samsung_tuna-a42548a18866e87092db93b771e6c5b060d78401.zip kernel_samsung_tuna-a42548a18866e87092db93b771e6c5b060d78401.tar.gz kernel_samsung_tuna-a42548a18866e87092db93b771e6c5b060d78401.tar.bz2 | |
cputime: Optimize jiffies_to_cputime(1)
For powerpc with CONFIG_VIRT_CPU_ACCOUNTING
jiffies_to_cputime(1) is not compile time constant and run time
calculations are quite expensive. To optimize we use
precomputed value. For all other architectures is is
preprocessor definition.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <1248862529-6063-5-git-send-email-sgruszka@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/cputime.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h index 7a3817a..24b1244 100644 --- a/arch/s390/include/asm/cputime.h +++ b/arch/s390/include/asm/cputime.h @@ -42,6 +42,7 @@ __div(unsigned long long n, unsigned int base) #endif /* __s390x__ */ #define cputime_zero (0ULL) +#define cputime_one_jiffy jiffies_to_cputime(1) #define cputime_max ((~0UL >> 1) - 1) #define cputime_add(__a, __b) ((__a) + (__b)) #define cputime_sub(__a, __b) ((__a) - (__b)) |