This was stated on the z/VSE LISTSERV, can someone confirm (or deny) it?
Here is a quick tip. When running under VM with multiple VSE's it is
usually NOT a good idea to define multiple CPU's to VSE and expect turbo
dispacher to handle them. Why? Because z/VM will not dispach a VSE
unless it
On Wed, Sep 29, 2010 at 7:30 PM, Frank M. Ramaekers
framaek...@ailife.com wrote:
This was stated on the z/VSE LISTSERV, can someone confirm (or deny) it?
Here is a quick tip. When running under VM with multiple VSE's it is usually
NOT a good idea to define multiple CPU's to VSE and expect
I know you are a smart guy Rob, but I beg to differ with you on this point.
At least where VSE is concerned.
I have done this and can reproduce results at will (that is if I stilled
worked there).
Environment:
4 CPU z890.
8 gig real memory.
z/VM 5.4
7 production VSE's
VSE 2.7
z/VSE 3.1
With VSE's
VSE's turbo dispatcher is known not to be the best in avoiding MP overhead,
the VSE lab published tables with its MP overhead.
So, never draw conclusions from VSE tests in MP situations to apply them to
other environments.
And, I don't see where your measurement would disagree with what Rob often
On Wed, Sep 29, 2010 at 8:54 PM, Tom Huegel tehue...@gmail.com wrote:
With VSE's using only 1 CPU (non-dedicated) I carfully selected a one hour
job mix.
Giving VSE's 4 CPU's (non-dedicated) the same job mix ran close to 1hr
20min...
This is wall clock time, which in final analysis is the
: VMBearDad (AIM), mbhcpcvt (Y!)
The IBM z/VM Operating System IBMVM@LISTSERV.UARK.EDU wrote on 09/29/2010
02:52:15 PM:
From: Rob van der Heij rvdh...@velocitysoftware.com
To: IBMVM@LISTSERV.UARK.EDU
Date: 09/29/2010 02:52 PM
Subject: Re: z/VSE dispatch of multi-CPU under VM
Sent by: The IBM z/VM
IBM has said many, many times to never, never use more than 3 CPU's with
VSE, and even 3 is be bad with most work loads. This is due to the
overhead of the Turbo-Dispatcher. With 4 you were spinning the
dispatcher more than servicing the jobs.
Try your job with just 2 CPUs.
Tony Thigpen
OK .. maybe Cathrine M. will chime in I can't remember everything we tried,
but she takes notes.
If I remember correctly nothing worked better than 1 CPU. I set share
manually and let VMRMSVM do it dynamically.
I think VMRMSVM did a better job overalll than I did manually.
On Wed, Sep 29, 2010
With most workloads, IBM says to get the largest UNI you can.
Remember, with z/VSE, only one CPU can be used by a single partition at
a time. If you have a heavy CPU usage partition, like CICS, that uses up
all the cycles it can, then adding another CPU just adds overhead. The
only time I really
Operating System IBMVM@LISTSERV.UARK.EDU
To: IBMVM@LISTSERV.UARK.EDU IBMVM@LISTSERV.UARK.EDU
Sent: Wed Sep 29 18:55:45 2010
Subject: Re: z/VSE dispatch of multi-CPU under VM
With most workloads, IBM says to get the largest UNI you can.
Remember, with z/VSE, only one CPU can be used by a single partition
@LISTSERV.UARK.EDU
To: IBMVM@LISTSERV.UARK.EDU IBMVM@LISTSERV.UARK.EDU
Sent: Wed Sep 29 18:48:43 2010
Subject: Re: z/VSE dispatch of multi-CPU under VM
OK .. maybe Cathrine M. will chime in I can't remember everything we tried, but
she takes notes.
If I remember correctly nothing worked better than
11 matches
Mail list logo
