středa 28. září 2011

F16 power management test day will start this Thursday (2011-09-29)

Fedora 16 power management test day will start this Thursday (2011-09-29). The event will be mainly focused on laptops, but even desktop machines can be tested. Everybody is welcome to attend this event and your attendance will help us to make the PM in Fedora better. Special LiveCD was prepared for this event, thus it is really easy to attend. There were created several test cases. Going through all test cases take less an hour. Just visit the PM test day WWW page and follow the on-site instructions. If you find test cases you are not interested in (or if you don't have time to test it all), just test what you want and report the results, your feedback will be still valuable to us.

Power management guide for F15 was published

Power management guide for F15 went through doc team for language corrections and is finally available online: Let's focus on F16 :).

středa 14. září 2011

Power consumption comparison of Firefox browser on various platforms

Since I have more time during the summer, I have finally decided to do Firefox web browser power consumption comparison on various platforms. The goal was to compare power consumption in typical real world "browsing" scenarios.

Test description

I have created simple test script using iMacros Firefox addon to automatize browsing in 3 tabs, the following scenarios were implemented:
  1. videos playback + scrolling Youtube page.
  2. articles reading (simulated by scrolling the page).
  3. searching (search term typing simulation, scrolling the page, opening the result).
Every measurement lasted for 30 minutes and every test was measured three times and average values were counted. Before each test the system was left for 10 hours in idle to stabilize. Five 64 bit systems have been tested: Fedora 15, RHEL5, RHEL6, Windows 7, Windows Server 2008 R2. Latest SW updates were applied and default setting and no tunings (i.e. the Balanced power saver profile on Windows) were used. The following tests were performed:
  1. Active idle state with running Firefox with about:blank page.
  2. Scenario 1 with HTML5 Youtube videos playback and scenarios 2 and 3 in parallel.
  3. Scenario 1 with Flash Youfube videos playback and scenarios 2 and 3 in parallel.

Tests run on HP Proliant DL360 G6 with default BIOS settings / no tunings. For measurements, I used Chroma 66202 the ENERGY STAR/IEC 62301 compliant power meter. The total energy consumed on AC side was monitored. As data logger / power meter controller another machine was used not to influence the machine under test.


Latest available kernels and SW builds as available during the test day were used. I've used binary versions of Firefox from Mozilla website, except RHEL5, where Firefox had to be compiled (Firefox 5.0 binary version does not support RHEL5). Firefox version 5 and latest Flash (Beta 2 11.0.d1.98) was used.

Table 1: Used softwareare
SystemKernel / SW build
Windows 76.1.7601
Windows Server 2008 R26.1.7601
Idle state

For this test, Firefox has been running with about:blank for 30 minutes.

Table 2: Idle state
Pavg [W]
Eavg [Wh]
Fedora 1555.961327.9744
Windows 759.558329.7725
Windows Server 2008 R259.0285029.5077

From Table 2 you can see that all Linux distributions except RHEL5 has more or less the same power consumption on our testing platform. Increased power consumption in RHEL5 is probably mostly caused by older kernel (e.g. no tickless kernel). Windows in idle state needs more energy than Linux systems on our testing platform.

iMacros script with HTML5 Youtube videos

For this test, iMacros test was used as described above and Youtube was configured to use HTML5 video playback. RHEL5 couldn't participate in this test, because of insufficient dependencies.

Table 3: iMacros with HTML5 Youtube
Pavg [W]
Eavg [Wh]
Fedora 1565.682432.8338
Windows Server 2008 R265.174332.5799
Windows 765.814632.9000

There are no big differences in power consumption between measured systems on our testing platform. Interesting fact is that Windows systems had the same power consumption as Linux based ones although Windows systems needed more power in idle state.

iMacros script with Flash Youtube videos

This test is the same as previous one, but Firefox flash plugin was activated and Youtube was configured to use Flash for videos playback. This also activates Flash adverts on other pages.

Table 4: iMacros with Flash Youtube
Pavg [W]
Eavg [Wh]
Fedora 1568.957534.4711
Windows Server 2008 R265.858232.9218
Windows 768.246034.1154

Surprise here was Windows 2008 R2 Server in comparison with Windows 7. Power consumption on Windows 2008 R2 Server with Flash was almost the same as with HTML5.

Flash power consumption

This table shows difference between Table 4 and Table 3 which demonstrates saved energy when not using Flash.

Table 5: Flash power consumption
Pavg [W]
Eavg [Wh]
Fedora 153.27511.6373
Windows Server 2008 R20.68390.3419
Windows 72.43141.2154


Windows has bigger power consumption in idle state than Linux based systems on our testing platform. There are no big differences between Windows and Linux when browsing web without Flash, but Windows needs less energy when Flash is used. If you need Flash only for services which supports also HTML5, you should definitely use HTML5 to save energy.