More usched

7af1706b · Silas Boyd-Wickizer · 98c1ea02 · 7af1706b
--- a/user/usched.cc
+++ b/user/usched.cc
@@ -14,6 +14,11 @@ typedef uint64_t u64;
 #include "percpu.hh"
 #include "sched.hh"
 #include "queue.h"
+#include "uscopedperf.hh"
+#include "intelctr.hh"
+
+static auto perfgroup = ctrgroup(&intelctr::tsc);
+

 static int nprocs = NCPU;
 static int the_time = 5;
@@ -64,13 +69,14 @@ public:
  proc* steal(bool nonexec);
  void dump();

-  volatile u64 ncansteal_ __mpalign__;
-
  sched_stat stats_;
+  u64 ncansteal_;
+  
+  volatile bool cansteal_ __mpalign__;

 private:
  pthread_spinlock_t lock_;
-  sched_link head_;
+  sched_link head_ __mpalign__;;
 };
 percpu<schedule> schedule_;

@@ -109,6 +115,7 @@ schedule::schedule(void)
  head_.next = &head_;
  head_.prev = &head_;
  ncansteal_ = 0;
+  cansteal_ = false;
  pthread_spin_init(&lock_, 0);
 }

@@ -123,7 +130,8 @@ schedule::enq(proc* p)
  head_.prev->next = entry;
  head_.prev = entry;
  if (cansteal((proc*)entry, true))
-    ncansteal_++;
+    if (ncansteal_++ == 0)
+      cansteal_ = true;
  stats_.enqs++;
  pthread_spin_unlock(&lock_);
 }
@@ -131,6 +139,8 @@ schedule::enq(proc* p)
 proc*
 schedule::deq(void)
 {   
+  ANON_REGION("deq", &perfgroup);
+
  if (head_.next == &head_)
    return nullptr;

@@ -145,7 +155,8 @@ schedule::deq(void)
  entry->next->prev = entry->prev;
  entry->prev->next = entry->next;
  if (cansteal((proc*)entry, true))
-    --ncansteal_;
+    if (--ncansteal_ == 0)
+      cansteal_ = false;
  stats_.deqs++;
  pthread_spin_unlock(&lock_);
  return (proc*)entry;
@@ -154,14 +165,15 @@ schedule::deq(void)
 proc*
 schedule::steal(bool nonexec)
 {
-  if (ncansteal_ == 0 || pthread_spin_trylock(&lock_))
+  if (!cansteal_ || pthread_spin_trylock(&lock_))
    return nullptr;

  for (sched_link* ptr = head_.next; ptr != &head_; ptr = ptr->next)
    if (cansteal((proc*)ptr, nonexec)) {
      ptr->next->prev = ptr->prev;
      ptr->prev->next = ptr->next;
-      --ncansteal_;
+      if (--ncansteal_ == 0)
+        cansteal_ = false;
      ++stats_.steals;
      pthread_spin_unlock(&lock_);
      return (proc*)ptr;
@@ -187,6 +199,7 @@ stealit(void)
 {
  proc* p;

+  ANON_REGION("stealit", &perfgroup);
  for (int i = 0; i < NCPU; i++) {
    if (i == myid_)
      continue;
@@ -269,5 +282,6 @@ main(int ac, char** av)

  sleep(1);
  worker((void*)0);
+  scopedperf::perfsum_base::printall();
  return 0;
 }