1.1 --- a/tools/xentrace/xentrace.c	Tue Apr 13 15:38:27 2010 +0100
     1.2 +++ b/tools/xentrace/xentrace.c	Tue Apr 13 18:18:36 2010 +0100
     1.3 @@ -149,6 +149,7 @@ void membuf_reserve_window(unsigned cpu,
     1.4  {
     1.5      struct cpu_change_record *rec;
     1.6      long need_to_consume, free, freed;
     1.7 +    int last_cpu = -1;
     1.8  
     1.9      if ( membuf.pending_size > 0 )
    1.10      {
    1.11 @@ -193,11 +194,25 @@ void membuf_reserve_window(unsigned cpu,
    1.12  
    1.13          if ( need_to_consume > 0 )
    1.14          {
    1.15 +            last_cpu = rec->data.cpu;
    1.16              MEMBUF_CONS_INCREMENT(freed);
    1.17              need_to_consume -= freed;
    1.18          }
    1.19      } while( need_to_consume > 0 );
    1.20  
    1.21 +    /* For good tsc consistency, we need to start at a low-cpu buffer.  Keep
    1.22 +     * skipping until the cpu goes down or stays the same. */
    1.23 +    rec = (struct cpu_change_record *)MEMBUF_POINTER(membuf.cons);
    1.24 +    while ( rec->data.cpu > last_cpu )
    1.25 +    {
    1.26 +        last_cpu = rec->data.cpu; 
    1.27 +
    1.28 +        freed = sizeof(*rec) + rec->data.window_size;
    1.29 +        
    1.30 +        MEMBUF_CONS_INCREMENT(freed);
    1.31 +        rec = (struct cpu_change_record *)MEMBUF_POINTER(membuf.cons);
    1.32 +    }
    1.33 +
    1.34  start_window:
    1.35      /*
    1.36       * Start writing "pending" data.  Update prod once all this data is