Re: issue with mmdrv.exe process consuming high CPU

[James Pulley]

You will never be able to use more than 4GB on your load generator as MDRV is a 32 bit process.

Clearly you are CPU bound for the number of users.  Split your users onto more load generators.   There are a number of reasons that you could be using CPU.   Assuming you are monitoring your load generator's health during the test, can you tell us what the split on USER and SYSTEM is.   This will point to either your code or I/O issues that are impacting the CPU more.

But in general I would never place 3000 users on a single load generator as this is just screaming for Mr Murphy to show up and play havoc with your test execution.

I assume that if you have (at least) a 3000 user license that you have a pool of a dozen or more load generators available to you as the load generator investment would be onlya  small fraction of the tool investment.  Use them.   Any given test should include a minimum of 3 (two primary load plus one control).  Maximum is dictated by how heavy your users are.

On Thursday, August 2, 2012 1:07:11 AM UTC-4, joel wrote:

Hi,

We are running 3000 Vuser Load on a Load generator (4 CPU, 2.7 GHZ, 32 GB RAM).During the ramp-up around 2000 users the CPU Utilization goes to 100% for LG.

Analysing the Perfmon logs of the LG, we analysed that out of multiple mmdrv.exe processes few (2-3) start consuming 25-30% CPU utilization each, where as the other process (mmdrv.ex around 20) consume 2-3%. Memory graphs concluded that Memory was utilised arounfd 2 GB.

The Vuser are executed as Thread and logging is disabled.
Load Runner version 11.0 is used.

Let us know any solution, apart from increasing the CPU and Adding LG.

Thanks,
Rohan Joel

[rupes...@wipro.com]

I have never seen any mdrv consuming so much RAM!!

 

 

Rupesh Garg

(001)-781-786-1243 | rupes...@wipro.com

 

From: lr-loa...@googlegroups.com [mailto:lr-loa...@googlegroups.com] On Behalf Of joel
Sent: Thursday, August 02, 2012 10:52 PM
To: LR-Loa...@googlegroups.com
Subject: Re: issue with mmdrv.exe process consuming high CPU

 

Does all the mdrv processes use max 4GB or a single MDRV process use 4GB. we have seen Memory utilization goes upto max 12 GB during the test.

We are using 2 LGs of similar configuration mentioned above. and the CPU Reaches 100% (due to mmdrv.exe process ) after a certain time (arounrd 7 min). and when the CPU reaches 100% the user load is around 700 users in each of the machine. (ramp up 25 users in 15 sec also tried with 30 sec)

The system processes uses around 4% of the CPU and user processes uses rest of the CPU during the test. Also we have tried running the script without any C/C++ code and with hitting the server with only one request.

I am sure that with the above configuration the LGs should be able to handle more than 1000 user load if not 3000 userload.

Is it something to do with mdrv being corrupt. (have tried uninstall LG agent and reinstalled ). Is there any free tool which repairs mdrv .

Is there any registry setting which needs to be changed or any configuration which needs to be changes in mdrv.

Let me know

Thanks,
Rohan Joel

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[Mohammed Khan]

Hi Rohan,

 

To create a Live scenario, the best practice is to apply the load from different injectors rather from one. Probably create Virtual images with the required OS and Install LGs on them.

Agreed with James comments regarding investment on the LGs.

 

Thanks,

Hussain Khan

[James Pulley]

The multi threaded driver, m|mdrv.exe, is a 32 bit process and the
maximum address space that it can address is 2^32 bytes, or 4GB. You
cannot fight logic and physics to make it see more.

Assuming you are running on win64 because of the high RAM on the host
you will want to research the WOW32 subsytem on windows to see how
individual processes which are 32 bit are handled. Does ech receive
its own 32 bit address space or is it shared? If a parent process
starts a child process does this have any impact on the WOW32
subsystem and how it allocates space for a program or set of programs?

'Pulley

On Aug 3, 1:58 am, joel <nikj...@gmail.com> wrote:
> I am not concerned what you have seen and not.. If you havew solution for
> the problem let me know.

[Franklin Inbaraj]

Put some load on localhost and check whether you see the same issue or not... Just to ensure nothing wrong with LGs/installation

Regards,

Franklin Inbaraj

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Regards,
Franklin Inbaraj

[Franklin Inbaraj]

So its clear something wrong with LoadGens

Regards,

Franklin Inbaraj

On Sat, Aug 4, 2012 at 6:44 AM, joel <nik...@gmail.com> wrote:

On localhost it works fine

On Saturday, August 4, 2012 12:34:17 AM UTC+10, Frank wrote:

Put some load on localhost and check whether you see the same issue or not... Just to ensure nothing wrong with LGs/installation

Regards,

Franklin Inbaraj

On Fri, Aug 3, 2012 at 7:25 AM, James Pulley <loadrunner-lists@jamespulley.com> wrote:

The multi threaded driver, m|mdrv.exe, is a 32 bit process and the
maximum address space that it can address is 2^32 bytes, or 4GB.  You
cannot fight logic and physics to make it see more.

Assuming you are running on win64 because of the high RAM on the host
you will want to research the WOW32 subsytem on windows to see how
individual processes which are 32 bit are handled.  Does ech receive
its own 32 bit address space or is it shared?  If a parent process
starts a child process does this have any impact on the WOW32
subsystem and how it allocates space for a program or set of programs?

'Pulley

On Aug 3, 1:58 am, joel <nikj...@gmail.com> wrote:
> I am not concerned what you have seen and not.. If you havew solution for
> the problem let me know.

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Regards,
Franklin Inbaraj

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Regards,
Franklin Inbaraj