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authorIngo Molnar <mingo@elte.hu>2008-08-11 13:27:47 +0200
committerIngo Molnar <mingo@elte.hu>2008-08-11 13:27:47 +0200
commitc4c0c56a7a85ed5725786219e4fbca7e840b1531 (patch)
treec9d6b35a571fd5e80ddf5bf4a60142480eaa18d8 /arch/ia64/include/asm/timex.h
parentrcu classic: new algorithm for callbacks-processing(v2) (diff)
parentMerge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/c... (diff)
downloadlinux-c4c0c56a7a85ed5725786219e4fbca7e840b1531.tar.xz
linux-c4c0c56a7a85ed5725786219e4fbca7e840b1531.zip
Merge branch 'linus' into core/rcu
Diffstat (limited to 'arch/ia64/include/asm/timex.h')
-rw-r--r--arch/ia64/include/asm/timex.h42
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/timex.h b/arch/ia64/include/asm/timex.h
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+++ b/arch/ia64/include/asm/timex.h
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+#ifndef _ASM_IA64_TIMEX_H
+#define _ASM_IA64_TIMEX_H
+
+/*
+ * Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+/*
+ * 2001/01/18 davidm Removed CLOCK_TICK_RATE. It makes no sense on IA-64.
+ * Also removed cacheflush_time as it's entirely unused.
+ */
+
+#include <asm/intrinsics.h>
+#include <asm/processor.h>
+
+typedef unsigned long cycles_t;
+
+extern void (*ia64_udelay)(unsigned long usecs);
+
+/*
+ * For performance reasons, we don't want to define CLOCK_TICK_TRATE as
+ * local_cpu_data->itc_rate. Fortunately, we don't have to, either: according to George
+ * Anzinger, 1/CLOCK_TICK_RATE is taken as the resolution of the timer clock. The time
+ * calculation assumes that you will use enough of these so that your tick size <= 1/HZ.
+ * If the calculation shows that your CLOCK_TICK_RATE can not supply exactly 1/HZ ticks,
+ * the actual value is calculated and used to update the wall clock each jiffie. Setting
+ * the CLOCK_TICK_RATE to x*HZ insures that the calculation will find no errors. Hence we
+ * pick a multiple of HZ which gives us a (totally virtual) CLOCK_TICK_RATE of about
+ * 100MHz.
+ */
+#define CLOCK_TICK_RATE (HZ * 100000UL)
+
+static inline cycles_t
+get_cycles (void)
+{
+ cycles_t ret;
+
+ ret = ia64_getreg(_IA64_REG_AR_ITC);
+ return ret;
+}
+
+#endif /* _ASM_IA64_TIMEX_H */