[IA64] VIRT_CPU_ACCOUNTING (accurate cpu time accounting)

This patch implements VIRT_CPU_ACCOUNTING for ia64,
which enable us to use more accurate cpu time accounting.

The VIRT_CPU_ACCOUNTING is an item of kernel config, which s390
and powerpc arch have.  By turning this config on, these archs
change the mechanism of cpu time accounting from tick-sampling
based one to state-transition based one.

The state-transition based accounting is done by checking time
(cycle counter in processor) at every state-transition point,
such as entrance/exit of kernel, interrupt, softirq etc.
The difference between point to point is the actual time consumed
during in the state. There is no doubt about that this value is
more accurate than that of tick-sampling based accounting.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/include/asm-ia64/cputime.h b/include/asm-ia64/cputime.h
index 72400a78002..f9abdec6577 100644
--- a/include/asm-ia64/cputime.h
+++ b/include/asm-ia64/cputime.h
@@ -1,6 +1,110 @@
+/*
+ * include/asm-ia64/cputime.h:
+ *		Definitions for measuring cputime on ia64 machines.
+ *
+ * Based on <asm-powerpc/cputime.h>.
+ *
+ * Copyright (C) 2007 FUJITSU LIMITED
+ * Copyright (C) 2007 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * If we have CONFIG_VIRT_CPU_ACCOUNTING, we measure cpu time in nsec.
+ * Otherwise we measure cpu time in jiffies using the generic definitions.
+ */
+
 #ifndef __IA64_CPUTIME_H
 #define __IA64_CPUTIME_H
 
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING
 #include <asm-generic/cputime.h>
+#else
+
+#include <linux/time.h>
+#include <linux/jiffies.h>
+#include <asm/processor.h>
+
+typedef u64 cputime_t;
+typedef u64 cputime64_t;
+
+#define cputime_zero			((cputime_t)0)
+#define cputime_max			((~((cputime_t)0) >> 1) - 1)
+#define cputime_add(__a, __b)		((__a) +  (__b))
+#define cputime_sub(__a, __b)		((__a) -  (__b))
+#define cputime_div(__a, __n)		((__a) /  (__n))
+#define cputime_halve(__a)		((__a) >> 1)
+#define cputime_eq(__a, __b)		((__a) == (__b))
+#define cputime_gt(__a, __b)		((__a) >  (__b))
+#define cputime_ge(__a, __b)		((__a) >= (__b))
+#define cputime_lt(__a, __b)		((__a) <  (__b))
+#define cputime_le(__a, __b)		((__a) <= (__b))
+
+#define cputime64_zero			((cputime64_t)0)
+#define cputime64_add(__a, __b)		((__a) + (__b))
+#define cputime64_sub(__a, __b)		((__a) - (__b))
+#define cputime_to_cputime64(__ct)	(__ct)
+
+/*
+ * Convert cputime <-> jiffies (HZ)
+ */
+#define cputime_to_jiffies(__ct)	((__ct) / (NSEC_PER_SEC / HZ))
+#define jiffies_to_cputime(__jif)	((__jif) * (NSEC_PER_SEC / HZ))
+#define cputime64_to_jiffies64(__ct)	((__ct) / (NSEC_PER_SEC / HZ))
+#define jiffies64_to_cputime64(__jif)	((__jif) * (NSEC_PER_SEC / HZ))
+
+/*
+ * Convert cputime <-> milliseconds
+ */
+#define cputime_to_msecs(__ct)		((__ct) / NSEC_PER_MSEC)
+#define msecs_to_cputime(__msecs)	((__msecs) * NSEC_PER_MSEC)
+
+/*
+ * Convert cputime <-> seconds
+ */
+#define cputime_to_secs(__ct)		((__ct) / NSEC_PER_SEC)
+#define secs_to_cputime(__secs)		((__secs) * NSEC_PER_SEC)
+
+/*
+ * Convert cputime <-> timespec (nsec)
+ */
+static inline cputime_t timespec_to_cputime(const struct timespec *val)
+{
+	cputime_t ret = val->tv_sec * NSEC_PER_SEC;
+	return (ret + val->tv_nsec);
+}
+static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
+{
+	val->tv_sec  = ct / NSEC_PER_SEC;
+	val->tv_nsec = ct % NSEC_PER_SEC;
+}
+
+/*
+ * Convert cputime <-> timeval (msec)
+ */
+static inline cputime_t timeval_to_cputime(struct timeval *val)
+{
+	cputime_t ret = val->tv_sec * NSEC_PER_SEC;
+	return (ret + val->tv_usec * NSEC_PER_USEC);
+}
+static inline void cputime_to_timeval(const cputime_t ct, struct timeval *val)
+{
+	val->tv_sec = ct / NSEC_PER_SEC;
+	val->tv_usec = (ct % NSEC_PER_SEC) / NSEC_PER_USEC;
+}
+
+/*
+ * Convert cputime <-> clock (USER_HZ)
+ */
+#define cputime_to_clock_t(__ct)	((__ct) / (NSEC_PER_SEC / USER_HZ))
+#define clock_t_to_cputime(__x)		((__x) * (NSEC_PER_SEC / USER_HZ))
+
+/*
+ * Convert cputime64 to clock.
+ */
+#define cputime64_to_clock_t(__ct)      cputime_to_clock_t((cputime_t)__ct)
 
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
 #endif /* __IA64_CPUTIME_H */