调度器40—sched_features Hello

基于 Linux-5.10

一、实验

1. kernel/sched/debug.c 中将以debugfs文件导出的 sched_feat_fops 文件改为procfs导出。

static const struct proc_ops sched_feat_proc_fops = {
    .proc_open = sched_feat_open,
    .proc_write = sched_feat_write,
    .proc_read = seq_read,
    .proc_lseek = seq_lseek,
    .proc_release = single_release,
};

proc_create("sched_features", 0644, NULL, &sched_feat_proc_fops);

备注：5.15内核上这个文件已经默认导出来了，# cat /sys/kernel/debug/sched/features。

2. enable/disable具体feature

# cat /proc/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY WAKEUP_PREEMPTION 
NO_HRTICK NO_DOUBLE_TICK NONTASK_CAPACITY NO_TTWU_QUEUE NO_SIS_AVG_CPU SIS_PROP NO_WARN_DOUBLE_CLOCK
RT_PUSH_IPI NO_RT_RUNTIME_SHARE NO_LB_MIN ATTACH_AGE_LOAD WA_IDLE WA_WEIGHT WA_BIAS UTIL_EST UTIL_EST_FASTUP
ALT_PERIOD BASE_SLICE

# echo NO_UTIL_EST > /proc/sched_features

# echo LB_MIN > /proc/sched_features

# cat /proc/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY WAKEUP_PREEMPTION
NO_HRTICK NO_DOUBLE_TICK NONTASK_CAPACITY NO_TTWU_QUEUE NO_SIS_AVG_CPU SIS_PROP NO_WARN_DOUBLE_CLOCK
RT_PUSH_IPI NO_RT_RUNTIME_SHARE LB_MIN ATTACH_AGE_LOAD WA_IDLE WA_WEIGHT WA_BIAS NO_UTIL_EST UTIL_EST_FASTUP
ALT_PERIOD BASE_SLICE