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提交 1f41a725 创建 作者: Silas Boyd-Wickizer's avatar Silas Boyd-Wickizer
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Keep track of kernel runq length, only try to steal when != 0.

This improves forexecbench performance on josmp by about 18%. Now steal_nonexec = 0 seems to have no affect or maybe a small negative affect.
上级 4c16796a
隐藏空白字符变更
内嵌 并排
正在显示 包含 11 行增加 和 1 行删除
kernel/sched.cc
浏览文件 @ 1f41a725
...@@ -19,6 +19,7 @@ enum { steal_nonexec = 1 }; ...@@ -19,6 +19,7 @@ enum { steal_nonexec = 1 };
struct runq { struct runq {
STAILQ_HEAD(queue, proc) q; STAILQ_HEAD(queue, proc) q;
struct spinlock lock; struct spinlock lock;
volatile u64 len __mpalign__;
__padout__; __padout__;
}; };
...@@ -119,6 +120,7 @@ addrun(struct proc *p) ...@@ -119,6 +120,7 @@ addrun(struct proc *p)
acquire(&q->lock); acquire(&q->lock);
STAILQ_INSERT_HEAD(&q->q, p, runqlink); STAILQ_INSERT_HEAD(&q->q, p, runqlink);
p->runq = q; p->runq = q;
q->len++;
release(&q->lock); release(&q->lock);
} }
...@@ -131,6 +133,7 @@ delrun(struct proc *p) ...@@ -131,6 +133,7 @@ delrun(struct proc *p)
q = p->runq; q = p->runq;
acquire(&q->lock); acquire(&q->lock);
STAILQ_REMOVE(&q->q, p, proc, runqlink); STAILQ_REMOVE(&q->q, p, proc, runqlink);
q->len--;
release(&q->lock); release(&q->lock);
} }
...@@ -147,6 +150,9 @@ steal(void) ...@@ -147,6 +150,9 @@ steal(void)
struct runq *q = &runq[(i+mycpu()->id) % ncpu]; struct runq *q = &runq[(i+mycpu()->id) % ncpu];
struct proc *p; struct proc *p;
if (q->len == 0)
continue;
// XXX(sbw) Look for a process to steal. Acquiring q->lock // XXX(sbw) Look for a process to steal. Acquiring q->lock
// then p->lock can result in deadlock. So we acquire // then p->lock can result in deadlock. So we acquire
// q->lock, scan for a process, drop q->lock, acquire p->lock, // q->lock, scan for a process, drop q->lock, acquire p->lock,
...@@ -160,6 +166,7 @@ steal(void) ...@@ -160,6 +166,7 @@ steal(void)
p->curcycles != 0 && p->curcycles > VICTIMAGE) p->curcycles != 0 && p->curcycles > VICTIMAGE)
{ {
STAILQ_REMOVE(&q->q, p, proc, runqlink); STAILQ_REMOVE(&q->q, p, proc, runqlink);
q->len--;
steal = p; steal = p;
break; break;
} }
...@@ -201,8 +208,10 @@ schednext(void) ...@@ -201,8 +208,10 @@ schednext(void)
q = &runq[mycpu()->id]; q = &runq[mycpu()->id];
acquire(&q->lock); acquire(&q->lock);
p = STAILQ_LAST(&q->q, proc, runqlink); p = STAILQ_LAST(&q->q, proc, runqlink);
if (p) if (p) {
STAILQ_REMOVE(&q->q, p, proc, runqlink); STAILQ_REMOVE(&q->q, p, proc, runqlink);
q->len--;
}
release(&q->lock); release(&q->lock);
popcli(); popcli();
return p; return p;
...@@ -216,6 +225,7 @@ initsched(void) ...@@ -216,6 +225,7 @@ initsched(void)
for (i = 0; i < NCPU; i++) { for (i = 0; i < NCPU; i++) {
initlock(&runq[i].lock, "runq", LOCKSTAT_SCHED); initlock(&runq[i].lock, "runq", LOCKSTAT_SCHED);
STAILQ_INIT(&runq[i].q); STAILQ_INIT(&runq[i].q);
runq[i].len = 0;
} }
} }
......
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