Date: Wed, 1 Dec 2010 10:55:58 GMT From: Hiro Aki <anycmd@mamemilk.com> To: freebsd-gnats-submit@FreeBSD.org Subject: bin/152738: vmstat, printhdr() doesn't work correctly with -p option under multiple CPUs Message-ID: <201012011055.oB1AtwxM037275@red.freebsd.org> Resent-Message-ID: <201012011100.oB1B0MGT008396@freefall.freebsd.org>
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>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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