NAME

       pmshub  -  tool  to monitor SN2 cache traffic and CPU uti­
       lization


SYNOPSIS

       pmshub [-A] [pmgadgets option ...]


DESCRIPTION

       pmshub is a tool for monitoring cache traffic on  SGI  SN2
       systems.  It will not work on any other platform.

       The command line options are:

       -A     Activate  SHub cache traffic performance monitoring
              on the target host, and then exit.  The target host
              is specified with the -h option to pmgadgets(1).

       -V     Print  the generated configuration file on standard
              output before running pmgadgets.  Brave individuals
              may use this to customize the configuration file.

       -t interval
              Specify  the  sample interval for updating metrics.
              For hosts on slow  or  congested  networks,  it  is
              advisable  to use a larger interval. The default is
              2 seconds.

       See the man page for  pmgadgets(1)  for  other  applicable
       options.

       The  pmshub  display  is  divided into cells, one for each
       node in the system.  On the left hand side, the  cell  for
       each node shows the logical node number and it's geograph­
       ical identity (rack, slot, slab and NASID);

       On the top right of each node cell a  scrolling  CPU  uti­
       lization  chart  for  each  CPU  on the node is displayed.
       These charts show "user" CPU  utilization  in  dark  blue,
       "nice" in cyan and "system" in red.

       The three strip charts across the bottom of each node cell
       show cache traffic as seen by the SHub  memory  controller
       on  each  SN2  node  board.   Each node board has it's own
       unique range of physical addreses and a load or  store  to
       any  particular  address  may  involve the SHub, cache and
       main memory on a remote node, but the  reference  will  be
       counted  as  either  local  or  remote for the originating
       node.  The scale ticks on the  left  side  of  each  chart
       range  from  0  to  8 million cache operations per second.
       Since each SN2 cacheline is 128 bytes, this can roughly be
       translated  into memory bandwidth for references that miss
       in the cache.  It important to note however that  none  of

       either load or store operations.

       Each strip chart shows green for local cache  traffic  and
       yellow  for (more expensive) remote off-node traffic.  The
       three charts have the following interpretation:

       Read Miss - Data
                 The read data miss rate  -  this  indicates  the
                 rate  of data load operations for addresses that
                 are not currently cached.  The instruction  miss
                 rate  metric  is available, but is not displayed
                 by pmshub.

       Write Line
                 The write back rate - this indicates the rate at
                 which  evicted  dirty cachelines ("victims") are
                 written back to main memory.

       Invalidates
                 The read/invalidate line rate -  this  indicates
                 the  rate  at which cachelines are being invali­
                 dated due to cacheline flushes or  store  opera­
                 tions  (which occur either locally or on another
                 node).

       Pressing the middle mouse button over a gadget inside  the
       pmshub  window  (or  pressing the space bar with the mouse
       pointer over a gadget) brings up the "Info"  dialog  which
       shows  the  current value (as text) for the metric(s) dis­
       played by the gadget under the  mouse  pointer.   Pressing
       the  right mouse button inside the pmshub window brings up
       a popup menu which allows one to terminate pmshub.  Press­
       ing  the  escape  key  (Esc) with the mouse pointer in the
       window will also terminate the application.  At this  time
       there  are  no  other  "actions" that can be launched from
       pmshub.


FILES

       $PCP_VAR_DIR/pmns/*
                 default PMNS specification files


PCP ENVIRONMENT

       Environment variables with the prefix  PCP_  are  used  to
       parameterize the file and directory names used by PCP.  On
       each installation, the  file  /etc/pcp.conf  contains  the
       local  values for these variables.  The $PCP_CONF variable
       may be used to specify an alternative configuration  file,
       as described in pcp.conf(4).


SEE ALSO

       pmgadgets(1) and pmgsys(1).


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