TUG Buzz! for Friday July 13, 2018

IN THIS ISSUE:

• Spectre Vulnerability - Responses
• iDev Cloud

Spectre Vulnerability

Last week we posed the following question to our readers.
Many thanks to those who responded!
(See responses below...)

Question: With respect to the issue of the "Spectre Vulnerability" and the related OS and firmware fix, TUG would be interested to know if you have seen any performance hits on Power 8 or Power 7+ hardware after applying the PTF and firmware updates. We are looking for any information from the IBM i community at large in relation to the SPECTRE patching as is relates to performance.

Responses

Tom Hoover  (IBM):

The performance impact (if any) will vary by application.

IBM is posting details about Spectra/Meltdown at these websites:
https://www.ibm.com/blogs/psirt/potential-impact-processors-power-family/
https://www-01.ibm.com/support/docview.wss?uid=nas8N1022433
https://www-01.ibm.com/support/docview.wss?uid=isg3T1026811

Neil Palmer  (DPS Data Processing Services):

On the DPS POWER7 system the full system backups in our Client LPARs have increased in time (significantly for the DPS LPAR, our largest), while the backup of the host partition (when the LPARs are down, and the NWSSTG spaces for them ae also saved) has decreased a little.

The 3 LPARs named here are all IBM i Client LPARs running under an IBM i Host LPAR on a POWER7 server (8202-E4B with 32GB memory and 20 disk arms, RAID-5, disk usage 65% of capacity).

– After Spectre/Meltdown Firmware PTF
04/16          DPS             6 hr 11 min
                   WEBSERV2  0 hr 46 min
                   DPSDEV01   1 hr 08 min
04/09          DPS             6 hr 11 min          
                   WEBSERV2  0 hr 45 min
                   DPSDEV01   1 hr 06 min

– Before Spectre/Meltdown Firmware PTF
04/02          DPS             5 hr 18 min         
                   WEBSERV2  0 hr 43 min
                   DPSDEV01   0 hr 58 min
03/26          DPS             5 hr 21 min
                   WEBSERV2  0 hr 44 min
                   DPSDEV01   0 hr 58 min

As you can see, really no impact on WEBSERV2, around 15% longer on DPSDEV01, and around 16% on DPS Prod.
We know the DPS LPAR is not configured optimally (4 x 500GB virtual disks, should really have more virtual disks of lower size).

The IBM i Host LPAR backup actually runs a little quicker after the Spectre/Meltdown Firmware PTFs were applied:

– After Spectre/Meltdown Firmware PTF
04/15          IBMiHOST    3 hr 59 min

– Before Spectre/Meltdown Firmware PTF
04/01          IBMiHOST    4 hr 16 min
03/25          IBMiHOST    4 hr 11 min

Asim, Hasan (GE Digital):

We have installed the FSP updates and PTFs related to the Spectre fixes for V7R2 on a couple of our large Power 880s and have seen about a 7-10% increase in CPU utilization.

Dan Duffy (Mid-Range):

Spectre? No problem.
Regards,
007

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iDev Cloud

Sign up now for iDevCloud! You will be able to:

• Share between multiple developers
• Get private library and storage
• Have access to most of the IBM i development tools
• Have all compilers for IBM i tools available

The Performance is monitored by system managers with adjustments as needed. The system is accessible at anytime from anywhere in the world. Just a computer and an internet connection are needed. Any work done on the system stays on the system until removed by its owner.

Contact Leo Lefebvre at leo@tug.ca to get started.

(*Free startup for TUG members.)

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