Attachment 172421 Details for Bug 253103 – Fixes spurious load spikes in /proc/loadavgrt

Fixes spurious load spikes in /proc/loadavgrt

loadavg_fixes_weird_loads.patch (text/x-patch), 1.82 KB, created by Luis Claudio R. Goncalves on 2007-08-24 14:39:41 UTC

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Creator: Luis Claudio R. Goncalves

Created: 2007-08-24 14:39:41 UTC

Size: 1.82 KB

patch

obsolete

>---------->
>
>Fixes spurious system load spikes observed in /proc/loadavgrt, as described in:
>
>  Bug 253103: /proc/loadavgrt issues weird results
>  https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=253103
>
>Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>>
>---
>
>diff --git a/kernel/sched.c b/kernel/sched.c
>index 811a502..c61609a 100644
>--- a/kernel/sched.c
>+++ b/kernel/sched.c
>@@ -2520,6 +2520,13 @@ unsigned long rt_nr_uninterruptible(void)
> 	for_each_online_cpu(i)
> 		sum += cpu_rq(i)->rt_nr_uninterruptible;
> 
>+	/*
>+	 * Since we read the counters lockless, it might be slightly
>+	 * inaccurate. Do not allow it to go below zero though:
>+	 */
>+	if (unlikely((long)sum < 0))
>+		sum = 0;
>+
> 	return sum;
> }
> 
>diff --git a/kernel/timer.c b/kernel/timer.c
>index 882ca9d..0e49bf6 100644
>--- a/kernel/timer.c
>+++ b/kernel/timer.c
>@@ -1432,23 +1432,25 @@ unsigned long avenrun_rt[3];
> static inline void calc_load(unsigned long ticks)
> {
> 	unsigned long active_tasks; /* fixed-point */
>+	unsigned long active_rt_tasks; /* fixed-point */
> 	static int count = LOAD_FREQ;
> 
> 	count -= ticks;
> 	if (unlikely(count < 0)) {
> 		active_tasks = count_active_tasks();
>+		active_rt_tasks = count_active_rt_tasks();
> 		do {
> 			CALC_LOAD(avenrun[0], EXP_1, active_tasks);
> 			CALC_LOAD(avenrun[1], EXP_5, active_tasks);
> 			CALC_LOAD(avenrun[2], EXP_15, active_tasks);
>-			count += LOAD_FREQ;
>-		} while (count < 0);
> #ifdef CONFIG_PREEMPT_RT
>-		active_tasks = count_active_rt_tasks();
>-		CALC_LOAD(avenrun_rt[0], EXP_1, active_tasks);
>-		CALC_LOAD(avenrun_rt[1], EXP_5, active_tasks);
>-		CALC_LOAD(avenrun_rt[2], EXP_15, active_tasks);
>+			CALC_LOAD(avenrun_rt[0], EXP_1, active_rt_tasks);
>+			CALC_LOAD(avenrun_rt[1], EXP_5, active_rt_tasks);
>+			CALC_LOAD(avenrun_rt[2], EXP_15, active_rt_tasks);
> #endif
>+			count += LOAD_FREQ;
>+
>+		} while (count < 0);
> 	}
> }
>

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Attachments on bug 253103: 161706 | 172421