what is impact of high xcal value in mpstat

what is impact of high xcal value in mpstat

Post by me » Fri, 01 Jun 2001 06:54:06



we have Sun 10K with 6 cpus and 8 gigs ram

we are having performance problems and using mpstat we noted wha tappears to
be high xcal value.

what is impact of a high value?  at waht point do we get conerned and what is
solution?

where is mpstat vlaues

CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
 36    5   4 24340   355   99  303   99   82 1032    0   862   18  80   0   2
 37    3   2 20304   191    2  278   94   77 1021    0   726   14  85   0   1
 38    4   3 36172  1000  859 1463  469   86  860    0   456   16  82   1   1
 39    6   6 27794   719  568 1069  333   93  980    0   908   21  75   1   3
 40    6   5 24456   202   15  348  119   97 1020    0  1007   18  80   0   2
 42    4   4 29026   203   17  331  116   87 1007    0   789   18  80   1   1
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
 36   17   3 29502   374  100  370  129  100 1205    0  1006   19  79   0   1
 37   36   4 25042   188    2  351  109   97 1240    0  1601   19  79   0   1
 38   74   8 31582  1044  898 1532  493   89 1090    0  1631   14  84   0   1
 39   33   6 30026  1054  912 1453  459   88 1164    0   792   16  81   1   2
 40   39   9 25132   221   22  381  130  102 1281    0  1969   19  79   0   1
 42   41   6 28558   214   24  382  123   97 1288    0   966   20  78   0   2
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
 36   51  10 27822   373  100  294  110   71  816    0   828   17  82   0   1
 37  116  13 24331   214    2  397  142   94 1050    0  1221   22  78   0   0
 38   39  11 29623  1024  881 1516  483   79  978    0   697   16  82   1   1
 39   39  13 28951   949  797 1410  430   93  964    0   894   16  82   1   1
 40   53  14 27547   223   40  379  120   93  979    0   953   24  75   0   0
 42  134   7 27478   239   38  495  132   89 1101    0  1517   19  80   1   0
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
 36    7   5 22287   365  100  343  106   88  913    0  1065   22  76   1   1
 37   26   9 28163   206    2  386  131   88  884    0  1033   24  74   0   1
 38   13   6 29041  1049  918 1571  481   89  978    0   768   20  78   0   1
 39    6   5 26324   797  649 1170  358  104  905    0  1113   24  75   1   0
 40    5   4 28968   212   18  363  122   94  935    0  1048   21  78   0   1
 42   10   3 27075   221   22  315  117   75  779    0   826   18  82   0   0

 
 
 

what is impact of high xcal value in mpstat

Post by Alan L. Stang » Fri, 01 Jun 2001 22:27:27



Quote:> we have Sun 10K with 6 cpus and 8 gigs ram

> we are having performance problems and using mpstat we noted wha tappears to
> be high xcal value.

> what is impact of a high value?  at waht point do we get conerned and what is
> solution?

> where is mpstat vlaues

> CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
>  36    5   4 24340   355   99  303   99   82 1032    0   862   18  80   0   2
>  37    3   2 20304   191    2  278   94   77 1021    0   726   14  85   0   1
>  38    4   3 36172  1000  859 1463  469   86  860    0   456   16  82   1   1
>  39    6   6 27794   719  568 1069  333   93  980    0   908   21  75   1   3
>  40    6   5 24456   202   15  348  119   97 1020    0  1007   18  80   0   2
>  42    4   4 29026   203   17  331  116   87 1007    0   789   18  80   1   1

What I think is interesting is the high SYS time, which I suppose is
related to the xcal counts.

What is this application doing that it's driving the machine to spend so
much time in the kernel?

Typically, xcal's are made to maintain virtual memory mapping coherency.
If you call munmap(), every processor needs to be "told" to tear down any
TLB entries and related state for that mapping.   The xcal column also
includes interprocessor interupts, which includes signal delivery and some
dispatcher stuff as well.

Hope this helps.

-- Alan

 
 
 

what is impact of high xcal value in mpstat

Post by Jason Occhialin » Sat, 02 Jun 2001 07:03:03


I'm pretty sure some of the high system time is related to the system spinning
trying to obtain mutexes. smtx column indicates the number of times the CPU failed
to obtain a mutex immediately. My understanding from reading*croft is if
mutexes are greater than 200/cpu system time will climb.

If it is was me, I'd go to www.setoolkit.com, grab the latest Virtual Adrian
release and see if it can direct you to the cause of the high mutex misses, i.e.
kernel contention. I personally think this is more of a worry than the xcal counts.

You may also want to read the caveats section of the mutex man page.

Sorry I couldn't be of more help.



> > we have Sun 10K with 6 cpus and 8 gigs ram

> > we are having performance problems and using mpstat we noted wha tappears to
> > be high xcal value.

> > what is impact of a high value?  at waht point do we get conerned and what is
> > solution?

> > where is mpstat vlaues

> > CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  wt idl
> >  36    5   4 24340   355   99  303   99   82 1032    0   862   18  80   0   2
> >  37    3   2 20304   191    2  278   94   77 1021    0   726   14  85   0   1
> >  38    4   3 36172  1000  859 1463  469   86  860    0   456   16  82   1   1
> >  39    6   6 27794   719  568 1069  333   93  980    0   908   21  75   1   3
> >  40    6   5 24456   202   15  348  119   97 1020    0  1007   18  80   0   2
> >  42    4   4 29026   203   17  331  116   87 1007    0   789   18  80   1   1

> What I think is interesting is the high SYS time, which I suppose is
> related to the xcal counts.

> What is this application doing that it's driving the machine to spend so
> much time in the kernel?

> Typically, xcal's are made to maintain virtual memory mapping coherency.
> If you call munmap(), every processor needs to be "told" to tear down any
> TLB entries and related state for that mapping.   The xcal column also
> includes interprocessor interupts, which includes signal delivery and some
> dispatcher stuff as well.

> Hope this helps.

> -- Alan

 
 
 

1. Unix-Mpstat-xcal(high) urgent

hi,
  My name is Omprakash when i tried see the performance of my cpu's
using MPSTAT command i got  xcal value higer than 200/sec,the
application is running on oracle 6,the application is a banking
software,the servers are the e6500.
  i need to know how xcal affects my performance &What is the solution

Kindly reply as early as possible

Regards
Omprakash

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