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HP-UX 11i v3 and Power Management

Recently, we were running to power and performance benchmarks on a server in our lab. We were using HP-UX 11i v3, update 5 and we were testing the impact of some of the power management features on the system.


The power management features that are available as of the HP-UX 11i v3 Update 4 release (0903 release) include Green Idle processors (pwr_idle_ctl), Green Active Processors (pstatectl), and more (see http://h71028.www7.hp.com/enterprise/w1/en/os/hpux11i-power-cooling-overview.html).


Green Idle processors basically takes the idle processors and drops it into a low power idle state, also known as the c-1 state. This is the same idle state that unutilized Instant Capacity processors are placed into automatically by the firmware. One interesting note is that when the OS places today's Itanium Montvale processor into C-1 state, it wakes up the processor every 10 milliseconds to handle a timing interrupt (if I remember correctly... I know the 10 ms is correct, but it could be a different interrupt). Anyway, basically, it wakes up the processor every 10 ms, at which point, it checks to see if there is any queue for it process, and if not, drops back into a lower power idle mode.


Green Active processors takes working processors and drops them into lower power p-states, basically slowing the frequency of the active processors. While the p-state can by set manually (to high performance or low power modes), the most balanced mode is the dynamic mode. This basically changes the p-State based on the activity level of the processor. If utilization is low, it drops it into a lower power mode. If it is in the 50% range, it increases the frequency, and around 80% utilization, it puts the processor in high power mode (P0 state).


So, why the explanation? Well, we were testing a system, and with Green Active processors and Green Idle processors enabled, it's maximum performance was within ~1.2% of our base run (and since we only ran it once for each run, it could be within the run to run variation). But here is the big difference: with both Green Active and Green Idle processors enabled, power consumption at 100% utilization dropped by about 8.5% and power consumption at idle dropped by about 11.7%


Now, I know that people who purchase mission critical systems want to get the maximum performance from those systems. However, would they be willing to activate these power controls since it has a minimal impact on performance? Even more importantly: we ship systems in maximum performance mode today, and those people who install the HP-UX 11i v3 updates that have these features can rest assured that the default is the same high performance mode that their previous releases that didn't have these commands used.


My question: have you enabled these power management features on your systems today? If not, why not? Should we change our maximum performance defaults, and ship our systems with power management enabled, and turn on dynamic power management with HP-UX 11i v3 future updates? Comments and feedback would be greatly appreciated.


Oh, and if you are interested in learning more? Check out the web site listed above, or the white paper at http://h20195.www2.hp.com/V2/GetDocument.aspx?docname=4AA2-5482ENW&cc=us&lc=en.


 


 

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About the Author(s)
  • I work as a Master Architect in HP Servers R & D group. I work with teams spread across the lab and outside to build solutions which are highly available on HP-UX, OpenVMS and Mission Critical Linux platforms. In particular I contribute to develop HP Serviceguard clusters, HP-UX Security and Middleware products. I have been with HP for last 17 years and have exposure to HA/DR field from both R & D and customer perspectives.
  • Kirk Bresniker is the Vice President/Chief Technologist for HP Business Critical Systems where he has technical responsibility for all things Mission Critical, including HP-UX, NonStop and scalable x86 platforms. He joined HP in 1989 after graduating from Santa Clara University and has been an HP Fellow since 2008.
  • I’m the worldwide marketing manager for HP NonStop. I’ll be blogging and tweeting out news as it relates to NonStop solutions – you can find me here and on twitter at @CarolynatHP
  • Cynthia is part of the HP ExpertOne team. ExpertOne offers professional IT training and certifications from infrastructure refresh to areas that span across the datacenter like Cloud and Converged Infrastructure.
  • Hi, I work on the HP Servers team as HP-UX worldwide product marketing manager. I´m interested in how customers use our technology and will be blogging about their stories and on how our products evolve to help their businesses be always on.
  • I have worked with NonStop systems since 1982. I am a Master Technologist for HP and am part of the IT SWAT organization, the Cloud SWAT and work with HP Labs. I report into the Enterprise Solutions and Architecture organization.
  • Joe Androlowicz is a Technical Communications and Marketing manager in HP’s NonStop Product Division. Joe is a 25 year journeyman in information systems design, instructional technologies and multimedia development. He left Apple Computer for Tandem Computers to help launch G03 and hasn’t looked back yet. He previously managed the program management team for the NonStop Education and Training Center and drove the development and growth of the NonStop Certification programs.
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  • Luke Oda is a member of the HP's BCS Marketing team. With a primary focus on marketing programs that support HP's BCS portfolio. His interests include all things mission-critical and the continuing innovation that HP demonstrates across the globe.
  • I am the Superdome 2 Product Manager. My interest is to learn how mission critical platform helps customers and would also like to share my thoughts on how Superdome has been helping customers and will continue to do so.
  • I work in the HP Servers marketing group, managing a marketing team responsible for marketing solutions for enterprise customers who run mission-critical workloads and depend on HP to keep their business continuously running.
  • Mohan Parthasarathy is a Technical Architect in the HP-UX lab. His primary focus currently is in the core kernel, platform enablement and virtualization areas of HP-UX. Mohan has worked on various modules of HP-UX, including networking protocol stacks, drivers, core kernel and virtualization
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  • Greetings! I am on the HP Enterprise Group marketing team. Topics I am interested in include Converged Infrastructure, Converged Systems and Management, and HP BladeSystem.
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  • Wendy Bartlett is a Distinguished Technologist in HP’s NonStop Enterprise Division, and focuses on dependability – security and availability - for the NonStop server line. She joined Tandem in 1978. Her other main area of interest is system architecture evolution. She has an M.S. degree in computer science from Stanford University.
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