Hallo Brian,

it may not be obvious, but NSRD is always multithreaded on a W2K system, but
that does not mean that it the work done by nsrd is distributed over
multiple CPUs. nsrd,nsrexecd and nsrpm are services, that means that there
will be threads just to enable them to run as service, like at least one
thread to monitor the communication with the service control manager. Other
threads could be used to implement ipc or process coordination. It is also
interesting to see that a "non-productive" nsrpm service has just as many
threads as nsrd (5) but nsrmmd only 3 (not a service). It would be more
interesting if the applications would use multiple threads for productive
work because then SMP-systems will be able to spread the workload.

You should also remember that multiple CPU's does not mean that the
application must be multithreaded, the system (device drivers, etc) must
also be services while the networker processes are active. During backup
there will be many processes that need time slices and it wouldn't help if
nsrd takes it all.

Bye
Ernie


-----Original Message-----
From: Narkinsky, Brian [mailto:Brian.Narkinsky AT DEP.STATE.FL DOT US]
Sent: Friday, June 13, 2003 9:34 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] Random technical question - Single threaded
process on multi-processor server


Seems a bit weird that NSRD is single threaded.  I am not at my server but,
it seems to me that I have seen multiple threads on a W2K box.  At any rate
it loads up my 2 processor W2K machine just fine.

Brian

-----Original Message-----
From: Reed, Ted G II [ITS] [mailto:ted.reed AT MAIL.SPRINT DOT COM]
Sent: Fri 6/13/2003 1:24 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Cc:
Subject: [Networker] Random technical question - Single threaded process on
multi-processor server



        Legato 6.1.3 on Solaris 8 (master + 2 SN):
                I've been working on various and sundry means to make our
        hardware architecture stretch to meet our backup and recovery needs.
        One of the primary issues we have is a weak brain.  In other words,
we
        do enough work at any given time slice that the master NSRD process
is
        maxing out an entire single 400MHz processor on a 4x400 SUN e450.
        Meanwhile, the other 3 cpus are doing practically nothing.  Our
storage
        nodes still seem to have room to grow as I/O-data movers, but each
extra
        bit sent to a node increases the overhead on the master and results
in
        further queuing of jobs waiting to be processed by the maxed out
NSRD
        job.
                We are investigating moving to a new Sun server master
        (v280/480) with 2x950MHz, but if I can take advantage of the 3
        underutilized cpus, then we may not need to spend the dollars.  So
in
        that vein, does anyone know of any wrappers/kernel mods/etc that
allow
        you to present a single "virtual" cpu to the process that is
back-ended
        by multi thread cpu process?

                My thought are:  if I have a wrapper (MyWrap) that accepts
cpu
        calls and translates them into a multi-threaded call to all 4 CPUs,
then
        I could up my overall cpu load towards the 100% mark.  Even if I
lost
        50% to overhead, I'd still have an effective doubling of process
        capabilities for the single process.  FYI, I'm thinking the
preference
        would be towards a "nohup" style of wrapper.  I.E. execution would
be
        "MyWrap -$switches -PID $PID" or "MyWrap -$switches nsrd &"
                There's no reason I could think of that you couldn't make it
        into some form of kernel mod or something (to build that 'single'
cpu
        box on multiple cpus to provide single-function server).  It's not
        something that everybody would want (why waste a perfectly good
        multi-proc box like that?) but I'd take sharing 4-as-1 CPU with the
        whole system versus where I am today maxing out 1 and leaving the
other
        3 out in the cold.

                Thank you all for your time and attention to my flight of
fancy.
        If anyone has any information concerning an actual product that
meets
        these basic requirements, I would LOVE to hear about it.  Thank you
        again.

                          --Ted G. Reed II, Engineering Storage Services
                             Pager: (888)510-4934   Phone: (913)794-7826

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