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authorStanislaw Gruszka <sgruszka@redhat.com>2009-07-29 10:15:29 (GMT)
committerIngo Molnar <mingo@elte.hu>2009-08-03 12:48:36 (GMT)
commita42548a18866e87092db93b771e6c5b060d78401 (patch)
tree897acf5794920ec9c6fd7f87af63908d0c1988f9 /arch/powerpc/include/asm/cputime.h
parentd1e3b6d195770bd422e3229b88edfc154b6a27dd (diff)
downloadlinux-fsl-qoriq-a42548a18866e87092db93b771e6c5b060d78401.tar.xz
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/powerpc/include/asm/cputime.h')
-rw-r--r--arch/powerpc/include/asm/cputime.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h
index f42e623..fa19f3f 100644
--- a/arch/powerpc/include/asm/cputime.h
+++ b/arch/powerpc/include/asm/cputime.h
@@ -18,6 +18,9 @@
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
#include <asm-generic/cputime.h>
+#ifdef __KERNEL__
+static inline void setup_cputime_one_jiffy(void) { }
+#endif
#else
#include <linux/types.h>
@@ -49,6 +52,11 @@ typedef u64 cputime64_t;
#ifdef __KERNEL__
/*
+ * One jiffy in timebase units computed during initialization
+ */
+extern cputime_t cputime_one_jiffy;
+
+/*
* Convert cputime <-> jiffies
*/
extern u64 __cputime_jiffies_factor;
@@ -89,6 +97,11 @@ static inline cputime_t jiffies_to_cputime(const unsigned long jif)
return ct;
}
+static inline void setup_cputime_one_jiffy(void)
+{
+ cputime_one_jiffy = jiffies_to_cputime(1);
+}
+
static inline cputime64_t jiffies64_to_cputime64(const u64 jif)
{
cputime_t ct;