From 2eec9a3688ab8a673a058312388cfff640acdd13 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Mon, 19 Nov 2018 00:58:00 +0100
Subject: Drop SIMPLE_CLOCK support

This wasn't building and is not useful with nowaday's hardware.

* configfrag.ac (SIMPLE_CLOCK): Do not define.
* kern/sched.h [SIMPLE_CLOCK] (sched_usec): Remove variable declaration.
* kern/sched_prim.c [SIMPLE_CLOCK] (sched_usec): Remove variable.
[SIMPLE_CLOCK] (sched_init): Do not initialize sched_usec variable.
[SIMPLE_CLOCK] (recompute_priorities): Do not tinker sched_usec
variable.
* kern/thread.c [SIMPLE_CLOCK] (thread_info): Do not ajust for clock
drift.
---
 kern/sched.h      |  9 ---------
 kern/sched_prim.c | 20 --------------------
 kern/thread.c     |  7 -------
 3 files changed, 36 deletions(-)

(limited to 'kern')

diff --git a/kern/sched.h b/kern/sched.h
index 8a4ec75b..588e0aa6 100644
--- a/kern/sched.h
+++ b/kern/sched.h
@@ -166,13 +166,4 @@ MACRO_BEGIN							\
 			(thread)->processor_set->sched_load;	\
 MACRO_END
 
-#if	SIMPLE_CLOCK
-/*
- *	sched_usec is an exponential average of number of microseconds
- *	in a second for clock drift compensation.
- */
-
-extern int	sched_usec;
-#endif	/* SIMPLE_CLOCK */
-
 #endif	/* _KERN_SCHED_H_ */
diff --git a/kern/sched_prim.c b/kern/sched_prim.c
index 423c6c0e..96fabf59 100644
--- a/kern/sched_prim.c
+++ b/kern/sched_prim.c
@@ -64,10 +64,6 @@ int		min_quantum;	/* defines max context switch rate */
 
 unsigned	sched_tick;
 
-#if	SIMPLE_CLOCK
-int		sched_usec;
-#endif	/* SIMPLE_CLOCK */
-
 thread_t	sched_thread_id;
 
 timer_elt_data_t recompute_priorities_timer;
@@ -159,9 +155,6 @@ void sched_init(void)
 	queue_init(&action_queue);
 	simple_lock_init(&action_lock);
 	sched_tick = 0;
-#if	SIMPLE_CLOCK
-	sched_usec = 0;
-#endif	/* SIMPLE_CLOCK */
 	ast_init();
 }
 
@@ -1089,21 +1082,8 @@ void compute_my_priority(
  */
 void recompute_priorities(void *param)
 {
-#if	SIMPLE_CLOCK
-	int	new_usec;
-#endif	/* SIMPLE_CLOCK */
-
 	sched_tick++;		/* age usage one more time */
 	set_timeout(&recompute_priorities_timer, hz);
-#if	SIMPLE_CLOCK
-	/*
-	 *	Compensate for clock drift.  sched_usec is an
-	 *	exponential average of the number of microseconds in
-	 *	a second.  It decays in the same fashion as cpu_usage.
-	 */
-	new_usec = sched_usec_elapsed();
-	sched_usec = (5*sched_usec + 3*new_usec)/8;
-#endif	/* SIMPLE_CLOCK */
 	/*
 	 *	Wakeup scheduler thread.
 	 */
diff --git a/kern/thread.c b/kern/thread.c
index 8637e36f..29c26d44 100644
--- a/kern/thread.c
+++ b/kern/thread.c
@@ -1527,13 +1527,6 @@ kern_return_t thread_info(
 	    basic_info->cpu_usage = thread->cpu_usage /
 					(TIMER_RATE/TH_USAGE_SCALE);
 	    basic_info->cpu_usage = (basic_info->cpu_usage * 3) / 5;
-#if	SIMPLE_CLOCK
-	    /*
-	     *	Clock drift compensation.
-	     */
-	    basic_info->cpu_usage =
-		(basic_info->cpu_usage * 1000000)/sched_usec;
-#endif	/* SIMPLE_CLOCK */
 
 	    flags = 0;
 	    if (thread->state & TH_SWAPPED)
-- 
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