Index: head/sys/kern/sched_ule.c =================================================================== --- head/sys/kern/sched_ule.c +++ head/sys/kern/sched_ule.c @@ -360,17 +360,19 @@ /* * We need some randomness. Implement the classic Linear Congruential * generator X_{n+1}=(aX_n+c) mod m. These values are optimized for - * m = 2^32, a = 69069 and c = 5. This is signed so that we can get - * both positive and negative values from it by shifting the value - * right. - */ -static int sched_random(void) -{ - int rnd, *rndptr; - rndptr = DPCPU_PTR(randomval); - rnd = *rndptr * 69069 + 5; - *rndptr = rnd; - return(rnd); + * m = 2^32, a = 69069 and c = 5. We only return the upper 16 bits + * of the random state (in the low bits of our answer) to return + * the maximum randomness. + */ +static uint32_t +sched_random() +{ + uint32_t *rndptr; + + rndptr = DPCPU_PTR(randomval); + *rndptr = *rndptr * 69069 + 5; + + return (*rndptr >> 16); } #endif @@ -718,7 +720,7 @@ CPU_CLR(cpu, &cpumask); tdq = TDQ_CPU(cpu); load = tdq->tdq_load * 256; - rnd = sched_random() >> 26; /* -32 to +31 */ + rnd = sched_random() % 32; if (match & CPU_SEARCH_LOWEST) { if (cpu == low->cs_prefer) load -= 64; @@ -882,7 +884,7 @@ return; balance_ticks = max(balance_interval / 2, 1) + - ((sched_random() >> 16) % balance_interval); + (sched_random() % balance_interval); tdq = TDQ_SELF(); TDQ_UNLOCK(tdq); sched_balance_group(cpu_top);