>Number:         152738
>Category:       bin
>Synopsis:       vmstat, printhdr() doesn't work correctly with -p option under 
>multiple CPUs
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Dec 01 11:00:21 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Hiro Aki
>Release:        8.1.0
>Organization:
Any Command Reading Club
>Environment:
>Description:
vmstat with -P option under multi-CPU environment doesn't display the header 
correctly if it has a cpu unavailable. 

the reason is below:
in the function "printhdr()", ncpus  is the number of CPUs available, not the 
number of all CPUs. so it might have the case that printf() is not called 
enough times for the number of all CPUs. 

842:            for (i = 0; i < ncpus; i++) {
843:                    if (cpumask & (1ul << i))
844:                            printf("cpu%-2d    ", i);
845:            }

on the other hand, "pcpustats()", which display the state of multiple CPUs, 
this works fine, using maxid which is the number of all CPUs.  
1122:   for (i = 0; i <= maxid; i++) {
1123:           if ((cpumask & (1ul << i)) == 0)
1124:                   continue;
1125:           for (state = 0; state < CPUSTATES; ++state) {
1126:                   tmp = cur_cp_times[i * CPUSTATES + state];
1127:                   cur_cp_times[i * CPUSTATES + state] -= last_cp_times[i *
CPUSTATES + state];
1128:                   last_cp_times[i * CPUSTATES + state] = tmp;
1129:           }
1130:   }

>How-To-Repeat:
did the code inspection and haven't actually run the problem. don't have 
multi-cpu machine for the first place lol.
>Fix:
this is a patch for vmstat.c at revision 1.109
http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/usr.bin/vmstat/vmstat.c


*** vmstat.c    2010-11-29 23:18:40.000000000 +0900
--- vmstatCorrected.c   2010-11-29 23:20:21.000000000 +0900
***************
*** 169,175 ****
  static void   needhdr(int);
  static void   needresize(int);
  static void   doresize(void);
! static void   printhdr(int, u_long);
  static void   usage(void);
  
  static long   pct(long, long);
--- 169,175 ----
  static void   needhdr(int);
  static void   needresize(int);
  static void   doresize(void);
! static void   printhdr(int, u_long, int);
  static void   usage(void);
  
  static long   pct(long, long);
***************
*** 707,713 ****
        }
        for (hdrcnt = 1;;) {
                if (!--hdrcnt)
!                       printhdr(ncpus, cpumask);
                if (kd != NULL) {
                        if (kvm_getcptime(kd, cur.cp_time) < 0)
                                errx(1, "kvm_getcptime: %s", kvm_geterr(kd));
--- 707,713 ----
        }
        for (hdrcnt = 1;;) {
                if (!--hdrcnt)
!             printhdr(ncpus, cpumask, maxid);
                if (kd != NULL) {
                        if (kvm_getcptime(kd, cur.cp_time) < 0)
                                errx(1, "kvm_getcptime: %s", kvm_geterr(kd));
***************
*** 758,764 ****
                          errx(1, "%s", devstat_errbuf);
                          break;
                      case 1:
!                         printhdr(ncpus, cpumask);
                          break;
                      default:
                          break;
--- 758,764 ----
                          errx(1, "%s", devstat_errbuf);
                          break;
                      case 1:
!                         printhdr(ncpus, cpumask, maxid);
                          break;
                      default:
                          break;
***************
*** 827,833 ****
  }
  
  static void
! printhdr(int ncpus, u_long cpumask)
  {
        int i, num_shown;
      
--- 827,833 ----
  }
  
  static void
! printhdr(int ncpus, u_long cpumask, int maxid)
  {
        int i, num_shown;
      
***************
*** 839,845 ****
                (void)printf("disk");
        (void)printf("   faults         ");
        if (Pflag) {
!               for (i = 0; i < ncpus; i++) {
                        if (cpumask & (1ul << i))
                                printf("cpu%-2d    ", i);
                }
--- 839,845 ----
                (void)printf("disk");
        (void)printf("   faults         ");
        if (Pflag) {
!         for (i = 0; i <= maxid; i++) {
                        if (cpumask & (1ul << i))
                                printf("cpu%-2d    ", i);
                }


>Release-Note:
>Audit-Trail:
>Unformatted:
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