Attachment 153514 Details for Bug 197922 – Updated patch to create sched_random() to provide entropy in the scheduler.

[patch] Updated patch to create sched_random() to provide entropy in the scheduler.

create_sched_random_with_cpu_search_random.diff (text/plain), 1.76 KB, created by Harrison Grundy on 2015-02-25 10:34:11 UTC

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Creator: Harrison Grundy

Created: 2015-02-25 10:34:11 UTC

Size: 1.76 KB

patch

obsolete

>Index: sys/kern/sched_ule.c
>===================================================================
>--- sys/kern/sched_ule.c	(revision 278968)
>+++ sys/kern/sched_ule.c	(working copy)
>@@ -331,6 +331,8 @@
>     struct cpu_group *cg, int indent);
> #endif
> 
>+static int sched_random();
>+
> static void sched_setup(void *dummy);
> SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
> 
>@@ -359,6 +361,16 @@
> /*
>  * Print the threads waiting on a run-queue.
>  */
>+
>+static int sched_random() 
>+{
>+        int rnd, *rndptr;
>+        rndptr = DPCPU_PTR(randomval);
>+        rnd = (*rndptr = *rndptr * 69069 + 5) >> 26;
>+        return(rnd);
>+} 
>+
>+
> static void
> runq_print(struct runq *rq)
> {
>@@ -651,7 +663,7 @@
> 	cpuset_t cpumask;
> 	struct cpu_group *child;
> 	struct tdq *tdq;
>-	int cpu, i, hload, lload, load, total, rnd, *rndptr;
>+	int cpu, i, hload, lload, load, total, rnd;
> 
> 	total = 0;
> 	cpumask = cg->cg_mask;
>@@ -700,9 +712,8 @@
> 			CPU_CLR(cpu, &cpumask);
> 			tdq = TDQ_CPU(cpu);
> 			load = tdq->tdq_load * 256;
>-			rndptr = DPCPU_PTR(randomval);
>-			rnd = (*rndptr = *rndptr * 69069 + 5) >> 26;
>-			if (match & CPU_SEARCH_LOWEST) {
>+			rnd = sched_random();
>+                        if (match & CPU_SEARCH_LOWEST) {
> 				if (cpu == low->cs_prefer)
> 					load -= 64;
> 				/* If that CPU is allowed and get data. */
>@@ -861,14 +872,11 @@
> {
> 	struct tdq *tdq;
> 
>-	/*
>-	 * Select a random time between .5 * balance_interval and
>-	 * 1.5 * balance_interval.
>-	 */
>-	balance_ticks = max(balance_interval / 2, 1);
>-	balance_ticks += random() % balance_interval;
> 	if (smp_started == 0 || rebalance == 0)
> 		return;
>+
>+	balance_ticks = max(balance_interval / 2, 1) +
>+            (sched_random() % balance_interval);
> 	tdq = TDQ_SELF();
> 	TDQ_UNLOCK(tdq);
> 	sched_balance_group(cpu_top);

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Attachments on bug 197922: 153317 | 153415 | 153513 | 153514 | 153515 | 153516