Using VIRT_CPU_ACCOUNTING, ia64 utilize "timestamp at end of iowait"
like s390.
Not-Tested-by: Hidetoshi Seto <seto.hideto...@jp.fujitsu.com>
---
arch/ia64/include/asm/cputime.h | 2 +
arch/ia64/kernel/time.c | 43 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 44 insertions(+), 1 deletions(-)
diff --git a/arch/ia64/include/asm/cputime.h b/arch/ia64/include/asm/cputime.h
index e2d3f5b..6089cbd 100644
--- a/arch/ia64/include/asm/cputime.h
+++ b/arch/ia64/include/asm/cputime.h
@@ -24,6 +24,8 @@
# include <asm/processor.h>
# include <asm-generic/cputime_nsecs.h>
extern void arch_vtime_task_switch(struct task_struct *tsk);
+extern void ia64_record_iowait_exit(int cpu);
+# define arch_record_iowait_exit(cpu) ia64_record_iowait_exit(cpu)
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
#endif /* __IA64_CPUTIME_H */
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 71c52bc..37c907d 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -138,9 +138,50 @@ void vtime_account_system(struct task_struct *tsk)
}
EXPORT_SYMBOL_GPL(vtime_account_system);
+/*
+ * Nasty trick to account iowait time as defined
+ */
+DEFINE_PER_CPU(u64, ia64_iowait_exit);
+
+void ia64_record_iowait_exit(int cpu)
+{
+ /* FIXME: ITC might not synchronized between cpus/sockets */
+ per_cpu(ia64_iowait_exit, cpu) = ia64_get_itc();
+}
+
void vtime_account_idle(struct task_struct *tsk)
{
- account_idle_time(vtime_delta(tsk));
+ struct thread_info *ti = task_thread_info(tsk);
+ cputime_t delta_stime, iowait_time;
+ __u64 now;
+
+ WARN_ON_ONCE(!irqs_disabled());
+
+ now = ia64_get_itc();
+
+ /*
+ * tsk must be idle process: its runtime is accumulated as system time
+ * (ac_utime must be 0) so convert it to idle time for accounting.
+ *
+ * in cycles:
+ * iowait_exit
+ * (idle_enter) | ac_stamp now(=idle_exit)
+ * -------+-------------------*------+------->
+ * <------- ac_stime ------->
+ *
+ * in cputime:
+ * (0)
+ * -------+-------------------*------+------->
+ * <----------- delta_stime --------->
+ * <-- iowait_time -->
+ */
+ delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
+ iowait_time = cycle_to_cputime(ti->ac_stime +
+ __ia64_per_cpu_var(ia64_iowait_exit) - ti->ac_stamp);
+ ti->ac_stime = 0;
+ ti->ac_stamp = now;
+
+ account_idle_and_iowait(0, iowait_time, delta_stime);
}
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
--
1.7.1
--
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