bk commit into 5.1 tree (knielsen:1.2617)

[knielsen]

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ChangeSet@stripped, 2007-10-12 13:23:37+02:00, knielsen@ymer.(none) +1 -0
  Reduce lock contention printout.
  Disable lock-to-cpu.

  storage/ndb/src/kernel/vm/mt/mt.cpp@stripped, 2007-10-12 13:23:31+02:00, knielsen@ymer.(none) +17 -2
    Reduce lock contention printout.
    Disable lock-to-cpu.

diff -Nrup a/storage/ndb/src/kernel/vm/mt/mt.cpp b/storage/ndb/src/kernel/vm/mt/mt.cpp
--- a/storage/ndb/src/kernel/vm/mt/mt.cpp	2007-10-12 07:45:23 +02:00
+++ b/storage/ndb/src/kernel/vm/mt/mt.cpp	2007-10-12 13:23:31 +02:00
@@ -141,9 +141,15 @@ inline void require(bool x)
 
 struct thr_spin_lock
 {
-  thr_spin_lock(const char * name) { m_lock = 0; m_name = name;}
+  thr_spin_lock(const char * name)
+  {
+    m_lock = 0;
+    m_name = name;
+    m_contended_count = 0;
+  }
 
   const char * m_name;
+  Uint32 m_contended_count;
   volatile unsigned m_lock;
 };
 
@@ -179,7 +185,14 @@ test:
   if (likely(xcng(val, 1) == 0))
     return;
 
-  printf("%s waiting for lock\n", sl->m_name);
+  /*
+   * There is a race conditions here on m_contended_count. But it doesn't
+   * really matter if the counts are not 100% accurate
+   */
+  Uint32 count = sl->m_contended_count++;
+  Uint32 freq = (count > 10000 ? 5000 : (count > 20 ? 200 : 1));
+  if ((count % freq) == 0)
+    printf("%s waiting for lock, contentions~=%u\n", sl->m_name, count);
 
   do {
     cpu_pause();
@@ -1074,6 +1087,7 @@ mt_thr_main(void *thr_arg)
     the numeric thread id in this slightly backwards way.
   */
   unsigned thr_no = selfptr - &(rep->m_thread[0]);
+#ifdef NDB_MT_LOCK_TO_CPU
   pid_t tid = (unsigned)syscall(SYS_gettid);
   ndbout_c("Tread %u started, tid=%u", thr_no, tid);
   ndbout_c("lock to cpu %u", (thr_no & 1));
@@ -1083,6 +1097,7 @@ mt_thr_main(void *thr_arg)
     CPU_SET(((thr_no & 1)*2 + 1), &mask);
     sched_setaffinity(tid, sizeof(mask), &mask);
   }
+#endif
 
   /*
     Now we need to somehow assign to this thread all blocks that will run in