FAQ


MiserWare Intelligent Software Power Management (ISPM)

Granola

cpufreq


MiserWare Intelligent Software Power Management (ISPM)

How does MiserWare ISPM work?

MiserWare ISPM is a set of algorithms for saving energy in a wide variety of workloads without affecting the performance of the system. These proprietary algorithms are at the heart of the current MiserWare products. In the MiserWare power management daemons, we leverage our ISPM algorithms to use dynamic voltage and frequency scaling (DVFS) technology. DVFS provides various power and performance settings for just about any modern processor, and when coupled with our algorithms can save significant system energy with no noticeable performance loss.

What are the system requirements for the MiserWare power management daemons?

The MiserWare power management daemons will run on any standard i386 or x86_64 system with DVFS support including multiprocessor and multicore systems. This translates to most systems 5 years old or newer. Additionally, DVFS must be enabled in the operating system and the BIOS (see this page for known BIOS options to enable). Because the daemons interact with the hardware through the operating system, they currently must be run on bare-metal installations of Linux or Microsoft Windows. We support 32- and 64-bit versions of the following operating systems:

  • Microsoft Windows XP SP2+, Vista, and 7
  • Debian 4.0, 5.0, unstable
  • Fedora 8, 9, 10, 11, 12
  • RHEL 4.7, 5.3
  • SLES 10
  • Ubuntu 7.04, 8.04, 8.10, 9.04, 9.10, 10.04

Other Linux operating systems are available upon request. There is no minimum memory requirement though 128MB or more is recommended. There is no minimum disk requirement though 1GB or more is recommended. Internet access is not required but recommended for access to upgrades, additional documentation, etc.

What kind of energy savings can I realistically expect?

Because MiserWare ISPM saves energy while your system is busy doing work, the energy savings depend on the workload. Thus, your energy savings will depend on how you are using your system. If you mostly surf the Internet and check email, the savings will be substantial and probably 30% or more. If you are playing the latest intensive graphic game without a high-end graphics card, the savings will probably be less; perhaps as low as 10%. But most likely, your system has many uses and the load varies with time. Our users typically experience savings of around 25%. Granola for Microsoft Windows updates savings information every 15 seconds in the main window. Granola for Linux periodically writes a savings report to syslog; you can check periodically to see your CPU energy savings. But, don’t take our word for it. Try it for yourself and share your experiences with us via feedback@miserware.com.

How are the savings numbers computed?

The savings reported by Granola are processor power numbers; the consumption and savings numbers are based on the models of processor power consumption we have created at MiserWare. Basically, we track how long you spend in each available power state and calculate savings by comparing against the default highest performance state for your system. Our techniques and assumptions are based on a decade of experience and validation using hardware power meters attached to servers, PCs, and laptops.

The energy, dollar, and carbon savings numbers require some assumptions about the relationship between processor speed and processor voltage, and furthermore on some assumptions about your processor type and the power required to run it. In the current version of Granola, the assumptions are very simple.

When Granola starts, it looks up the CPU in a power table data file we ship. The power table contains detailed power consumption data for the specific CPU and allows us to use a more accurate power model. If the CPU is not found then we fall back to using the following assumptions and calculations:

  • First, we assume that you are using a 90W processor, typical of many server and desktop processors available today, although laptops, some desktops, and now some servers may be equipped with lower power processors; if you know your processor power consumption, you can scale the results reported by Granola appropriately to get a more accurate measure of your savings. The Linux versions allow you to override the 90W default using the config file.
  • Second, we assume that your processor has a dynamic power range of 70%, meaning that 70% of the processor's power is affected when processor speed is changed.
  • Finally , we assume that the dynamic power changes linearly with the processor speed, so that running at half the maximum speed would halve the dynamic power consumption of the processor.

Here is an example. Let's say your processor has two speeds, 2GHz and 1GHz. Based on our first two assumptions, we assume your processor consumes 90W at 2GHz with a dynamic power of 90W * 70% = 63W, and a static power of 90W – 63W = 27W. Based on our third assumption, we estimate your processor power consumption at 1GHz to be 27W + (63W * (1GHz / 2GHz)) = 58.5W. So if your processor ran at its highest performance setting (2GHz) for an hour, it would consume 90W * 1 hour = 90Wh = .09kWh, and if it ran at 1GHz for an hour, it would consume 58.5W * 1 hour = 58.5Wh = .0585kWh, with a savings of 0.09kWh – 0.0585kWh = 0.0315kWh.

For each time step, the energy savings are calculated in this way, and the savings are added up over time to yield the savings numbers reported by MiserWare software. The Granola settings page allows you to set the assumption for the cost per kWh conversion to dollars (or in GBP). The conversion to carbon is based on standard techniques similar to those used by the U.S. Department of Energy. If your system has multiple physical processors (i.e. multiple CPUs in different sockets), Granola reports an aggregated total savings achieved for all physical processors.

Over time we will continue to add CPU entries to the power table allowing us to use the more sophisticated power model when calculating power savings and consumption.

Granola

What happened to MicroMiser?

In an effort to better get across our goals of saving the world, MicroMiser was renamed to Granola. We feel like the name Granola more accurately captures our goal of making a serious impact on the planet through the reduction of wasted energy. The core technology is the same in Granola and MicroMiser. The appearance and feature set of Granola is an improvement over MicroMiser; essentially, it is the newest version of MicroMiser. Except way better.

What’s in Granola for me?

By installing Granola, you get access to cutting-edge software that can reduce the energy consumption of your x86-based computer up to 35% without turning your machine off and with no noticeable performance loss. Essentially, you can help to do your part for the Earth for free – without having to inconvenience yourself or buy anything. By working with us to get as many users of Granola as possible, we can collectively achieve the ultimate goal of a noticeable impact on energy consumption worldwide.

Is there a commercial version of Granola?

Granola is free for personal use. Businesses may also be interested in ServerMiser ES, a turn-key management solution for network deployments of Granola. To purchase commercial licenses for these products, email sales@miserware.com for pricing information. MiserWare products are priced so that businesses earn ROI in 12 months or less.

When I try to install Granola, I get a package conflict with powernowd. What's going on?

Granola and powernowd both manage your CPU frequencies using DVFS. If they were run at the same time, they would compete with each other to set the frequencies of the processors in your system. Therefore, you need to remove the powernowd package prior to installing Granola:

  • Debian/Ubuntu:
    • sudo dpkg -r powernowd
  • RHEL, SLES, and Fedora
    • sudo rpm -e powernowd

What are the risks of using Granola?

Granola was designed for good, not evil:

  • Granola performance impact is negligible.
  • Granola does not mess with your current OS kernel or any of its modules.
  • Granola plays nicely with other software.
  • Granola estimates your energy savings without the need for additional hardware.
  • Granola is easy to add and remove since it uses native Linux packages.
  • Except for the energy savings, you’ll barely notice Granola is there.

Basically, we think the risks of using our software are minimal. For example, our software has less impact and is less intrusive than typical security software. But, don’t take our word for it, try it for yourself and share your experiences with us via feedback@miserware.com

Why are you giving Granola away for free?

We care about the environment and we are proud of the ability of our software to make computers more energy efficient. We also like when our laptops last longer and our servers cost less to operate. We want everyone to be able to use our software on their personal machines. So, early on we decided that in addition to creating enterprise power management software, we would also create a commercial-grade consumer version, Granola. Granola is free for your personal use and we have no intention of charging for it anytime soon.

We also need to create a thriving business so we can make computers even more energy efficient (trust us, we’ve got lots of other cool stuff on the drawing board). We are a small startup working out of a basement, and we provide Granola for free with the intent of helping to clean up the world. If you would like to donate to help us continue to provide Granola for free, we would welcome the funds. If you work for a company that you think would benefit from MiserWare software, we would love for you to refer them to us.

When will there be other platform support (e.g. Windows, Mac OSX) for Granola?

Shhhh! Who told you we were working on other platforms? Well, you got us. We do have plans to release a Windows version of Granola in the near future. If you’d like to be notified when the Windows version is available, send us an email via feedback@miserware.com. If you’d really like to see a version for Mac OSX or anything else (Commodore 64, anyone?), we’re ready to listen to our users. Let us know and we’ll do our best.

Are you going to release Granola as open source?

In an effort to provide you with the best possible software we can, we have included much of our proprietary technology in Granola. This technology is what makes it possible for Granola to save you energy while maintaining the performance of your machines. We have a responsibility to protect our intellectual property and build a thriving business since MiserWare development is privately funded, so for now we are not releasing Granola under an open source license.

The Python scripts released in Granola is currently under the BSD license (available here), and we plan to expand the amount of open source software we provide in the future.

Where can I find the statistics of the estimated energy savings for my computer?

For Microsoft Windows users the savings can be found on the main screen where they are updated every 15 seconds.

For Linux users the details are stored in the /var/log directory. Distros have different file names where the messages will be saved, examples are /var/log/daemon.log, /var/log/messages and /var/log/syslog.

Run the following shell command to obtain a verbose output of the statistics from the log file 

sudo grep Estimated\ energy /var/log/*

alternatively, to output it to a text file simply run the following (replace /path/to/filename.txt with your desired destination; 

sudo grep Estimated\ energy /var/log/* > /path/to/filename.txt

Example of output 

May 22 15:33:30 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.000007kWh (12.69%)
May 22 15:33:36 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.000017kWh (10.92%)
May 22 15:33:48 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.000055kWh (15.05%)
May 22 15:34:12 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.000177kWh (22.80%)
May 22 15:35:00 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.000347kWh (21.40%)
May 22 15:36:36 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.001106kWh (33.79%)
May 22 15:39:48 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.002735kWh (41.23%)
May 22 15:46:12 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.005992kWh (44.99%)
May 22 15:59:00 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.011905kWh (44.54%)
May 22 16:24:36 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.021855kWh (40.85%)
May 22 17:15:48 ubuntu granola[4519]: Estimated energy saved since Granola start: 0.038902kWh (36.34%)
How is Granola different from Intel's SpeedStep, AMD's PowerNow!, Cool'n'Quiet, etc.?

This is a bit like comparing apples to oranges. Intel SpeedStep, AMD PowerNow!, and Cool'n'Quiet provide an application programming interface (API) for utilizing dynamic voltage and frequency scaling (DVFS). That is, these technologies give other software (e.g. Granola) the ability to change the power consumption and frequency of the processor; i.e. these APIs do not carry out any power management themselves. Granola takes advantage of the availability of these tools. Granola dynamically and intelligently adjusts the power consumed by your machine based on CPU demand. The CPU management is implemented using algorithms developed by MiserWare that cleverly predict your CPU’s usage. Long story short, SpeedStep, PowerNow!, Cool'n'Quiet and others simply provide the
capability for carrying out DVFS. Software, like Granola, is needed to manage these technologies so they save you energy without impacting what you are doing.

How is Granola better than my current power-saving software (e.g., RMClock, Windows Power Manager, OnDemand, etc.)?

We’ve written a short paper describing the before and after effects of Granola under various benchmarks including DVD playback, gaming, and extensive document editing. The results are discussed on the following webpage:

http://grano.la/software/benchmark.php

Keep in mind that Granola dynamically and automatically adjusts the power consumed by your machine based on CPU demand. Think of a dimmer switch for a light bulb. When you are reading, you need your lights at full power. When you are looking to set mood lighting for that special someone, you might dim the lights a bit. Adding Granola to your PC is like adding an automatic dimmer switch that knows what mode you want without you having to touch the switch. When you are playing Half Life 2 Granola makes sure you’re running at full performance and power. When you are editing a word document, Granola might reduce the power of your CPU since it’s not going to affect your experience.

The key difference between Granola and other software that manages your CPU power is that Granola was designed to minimize performance loss ensuring you don’t waste energy unnecessarily and the power management scheme doesn’t impact your productivity. Basically, our automatic “dimmer switch” does a better job of predicting your needs than other techniques out there currently. Oh, and did we mention the reporting and interface are slick? So, free yourself from the limitations of the other guy’s software and feed your PC some Granola today!

How do I start the Granola PM Manager Service?

For Windows 7 and Vista:

  1. click Start, in the “Search programs and files” box, type Services and press Enter
  2. Scroll through the list and find the Granola PM Manager and double-click it
  3. Press the Start button near the bottom of the window
  4. Click OK

For Windows XP:

  1. Navigate to the Granola installation folder (C:\Program Files\MiserWare\Granola by default)
  2. Double click the GranolaManager.exe file
  3. If the problem persists, you can check the log file, usually at C:\Documents and Settings\All Users\Application Data\MiserWare\Granola\granola_manager.[your user name].log, where [your user name] is (surprise!) your login username.

cpufreq

What is cpufreq?

cpufreq is a Linux kernel subsystem that provides a standard interface for modifying the frequency and voltage at which the processor in your system is operating. The underlying technique is usually called dynamic voltage and frequency scaling, or DVFS. In terms of the MiserWare power management daemon (Granola), cpufreq does the actual work of moving the CPU devices in and out of their power states based on the output of our algorithms. Without cpufreq, our power management daemons cannot start.

A given installation of cpufreq has two primary components: a CPU driver, which interacts directly with the processor to discover capabilities and scale the frequency and voltage, and a governor which decides how and when the frequency changes should occur. MiserWare power management daemons use the userspace governor, which exports control of the frequencies to userspace via a /sys/ interface.

Are there any unsupported cpufreq CPU drivers?

Yes. p4-clockmod, gx-suspmod, and cpufreq-nforce2 are unsupported in the current generation of MiserWare software. The reasoning is that these two drivers are not actually doing DVFS; rather, they are doing things that kind of act like DVFS. Specifically, p4-clockmod (for some Intel processors) is doing only frequency scaling and no voltage scaling. This means that you will not experience any power savings, and due to the nature of the clock modulation, you may experience a performance hit that wouldn't be present in a DVFS-capable system. cpufreq-nforce2 (for Nvidia AMD XP boards) actually provides front-side bus scaling, which is not modeled by the MiserWare algorithms. gx-suspmod (for Geode processors) emulates DVFS by turning the clock for the CPU off for some duration based on the chosen “frequency”. This can yield an unpredictable performance impact of different states.

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