Richard The overhead to the fetch-causer is very minimal as SDSF MFM works by having a CSVFETCH dynamic exit that copies the payload from the FTCHX parameter list into a circular HV-COMM queue. The path length is quite small.
The overhead you might see is extra CPU used in the SDSFAUX address space, specifically the HSFMFMMN subtask as it periodically drains the HV-COMM queue and processes the payloads. Depending on your requirements, you can select 3 levels of detail on the FEATURE statement in ISFPRMxx : Level(1) - SDSF summaries the data on just the dsname Level(2) - SDSF additionally summarizes the data by dsname+modname Level(3) - SDSF additionally summarizes the data by dsname+modname+jobname Also note that you can dynamically start and stop the MFM feature at any time using "F SDSF,S MFM" and "F SDSF,P MFM". The processed data is kept until you issue "F SDSF,R MFM" which will reset the summary tables in SDSFAUX private storage. You can track MFM statistics with "F SDSF,D MFM" and the SDSF task CPU usage with "F SDSF,D TASK" Hope that helps Rob Scott Rocket Software ________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of rpinion865 <[email protected]> Sent: 15 July 2026 10:08 AM To: [email protected] <[email protected]> Subject: SDSF MFM Feature EXTERNAL EMAIL Does anybody have information regarding the SDSF MFM feature and CPU usage/overhead? I have turned it on for the TECH and Development LPARs. But I am concerned about what might happen on the Production LPAR. Thanks in advance. Richard Pinion "Confidentially doc, I am the wabbit." Bugs Bunny Sent with [Proton Mail](https://proton.me/mail/home<https://proton.me/mail/home>) secure email. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ================================ Rocket Software, Inc. and subsidiaries ? 77 Fourth Avenue, Waltham MA 02451 ? Main Office Toll Free Number: +1 855.577.4323 Contact Customer Support: https://my.rocketsoftware.com/RocketCommunity/RCEmailSupport Unsubscribe from Marketing Messages/Manage Your Subscription Preferences - http://www.rocketsoftware.com/manage-your-email-preferences Privacy Policy - http://www.rocketsoftware.com/company/legal/privacy-policy ================================ This communication and any attachments may contain confidential information of Rocket Software, Inc. All unauthorized use, disclosure or distribution is prohibited. If you are not the intended recipient, please notify Rocket Software immediately and destroy all copies of this communication. Thank you. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
