Mark,

the TSM client by design is multi-threaded since more than five years. But
till now I have not seen *any* multi-threaded application able to
simultaneously run one single thread on many processors. This is a
fundamental issue - you probably recall, the thread idea was invented when
we wanted to overrun the single-processor-per-process limitation.

The problem Duane is facing is "when I need another thread" and is deeply
in TSM client's design. By design client is creating one producer thread
and one consumer threads (I am using Andy Raibeck's terms - producer and
consumer). Each such thread is working on its own batch of work and is
communicating to the server through its own session.

Only if RESOURceutilization is increased (as Richard was explaining) you
can get more sessions. Only having those sessions the additional threads
will have a communication channel to the server and will be able to
perform any work. Thus limiting the number of sessions, we are limiting
the *maximum* number of threads the client can have.

(I KNOW Mark knows what I will write now but it is addressed to Duane)
Having resourceutilization increased *does not* mean automagically more
threads will be used. TSM client is having one producer-collector pair of
thread for each filesystem/filespace. If for example resourceutilization=6
but there is only one filesystem, the client will start one pair and two
sessions. In such cases VIRTUALMountpoint option might help.
Another consideration is processor power. If workload management thread
finds the processor(s) loaded enough, it will not start more threads. Same
example with resourceutilization=6 and now with 3 filesystems but having
processor power only for two producer-collector pairs - the third set will
not be started.

Standard disclaimer: I am not an IBMer but only TSM-literate person. I may
understand TSM internals incorrectly. Hopefully Andrew Raibeck and other
more knowledgeable people are watching closely the list and will correct
me if I am wrong.

Zlatko Krastev
IT Consultant






"Stapleton, Mark" <stapleto AT BERBEE DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
17.09.2003 18:28
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Re: WIN2K client only using 1 CPU for scanning.


From: Richard Sims [mailto:rbs AT BU DOT EDU]
>>I was under the impression that the TSM clients were multithreaded.
>>But I can not find any documentation that specifically identifies
>>multithreading as part of the client. Only that it will run on either
>>single cpu or multi CPU systems.

>Multi-session client (backup) was introduced in 3.7 (see the 3.7
Technical Guide redbook).  The number of sessions possible is governed
by the RESOURceutilization client option setting.<


That's not exactly what he asked about, Richard. He's referring to the
TSM client application being able to open multiple CPU threads, not
multiple TSM sessions.

--
Mark Stapleton (stapleton AT berbee DOT com)