Database Develop

[Q] Difference between different governors

What are the differences?
Which one is most power saving?

Had a look around, this guy here seems to explain it pretty well
http://forum.xda-developers.com/showthread.php?t=843406
Hope that helps.

Extracted from governors.txt from my mediafire site ...
CPUFreq governors in the Android Kernel
=======================================
+ performance
The CPUfreq governor "performance" sets the CPU statically to the highest frequency within the borders of scaling_min_freq and scaling_max_freq.
+ powersave
The CPUfreq governor "powersave" sets the CPU statically to the lowest frequency within the borders of scaling_min_freq and scaling_max_freq.
+ userspace
The CPUfreq governor "userspace" allows the user, or any userspace program running with UID "root", to set the CPU to a specific frequency by making a sysfs file "scaling_setspeed" available in the CPU-device directory.
+ ondemand
The CPUfreq governor "ondemand" sets the CPU depending on the current usage. To do this the CPU must have the capability to switch the frequency very quickly. There are a number of sysfs file accessible parameters: sampling_rate, show_sampling_rate_min, up_threshold, ignore_nice_load, sampling_down_factor.
+ conservative
The CPUfreq governor "conservative", much like the "ondemand" governor, sets the CPU depending on the current usage. It differs in behaviour in that it gracefully increases and decreases the CPU speed rather than jumping to max speed the moment there is any load on the CPU. This behaviour more suitable in a battery powered environment. The governor is tweaked in the same manner as the "ondemand" governor through sysfs with the addition of: freq_step & down_threshold
+ interactive
The CPUfreq governor "interactive" is designed for latency-sensitive, interactive workloads. This governor sets the CPU speed depending on usage, similar to "ondemand" and "conservative" governors. However, the governor is more aggressive about scaling the CPU speed up in response to CPU-intensive activity. The tuneable value for this governor are: min_sample_time & go_maxspeed_load
+ smartass (By [email protected])
The smartass governor is a complete rewrite of the interactive governor. CPU spends much more time at the lower frequencies for improved battery life. It gives the phone an automatic Screen Off profile, keeping speeds at a minimum when the phone is idle.
+ savagedzen (By [email protected])
SavagedZen is a governor based on the Smartass governor. With tweaks to paramaters which control how much and how fast cpu ramps up/down. Main difference versus Smartass is that cpu ramps down not in fixed steps, but based on cpu load heuristics, i.e. when cpu load falls below threshold (min_cpu_load), cpu immediately ramps down to a frequency derived from the measured load.
+ interactiveX (By [email protected])
Modified version of interactive with suspend code which locks at lowest clock speed when screen is off. Has a sleep+awake profile, meaning you don't need to set up manual profiles, it will lock at your minimum frequency during screen off
References:
- https://github.com/android/kernel_common/blob/android-2.6.39/Documentation/cpu-freq/governors.txt
- https://github.com/Savaged-Zen/Savaged-Zen/tree/master/drivers/cpufreq
- http://forum.xda-developers.com/showthread.php?p=12944012
- http://www.ziggy471.com/2010/11/07/smartass-governor-info

The OP question about the most power saving governor has been answered - 'powersave'. My question is - what about SavagedZen vs conservative?

[Q] Semaphore 1.6 beta

Unfortunately I can not post to dev section, so hopefully stratos will see my post here:
I had stock JVR with semaphore 1.5 (not v) on ext4 and everything was excellent with this brilliant kernel apart from the well known phone fc.
OC/UV was ok: quadrant scores were approx 1900-2400 on conservative cpu gov and 2500-3000 on ondemand gov.
Now, I flashed the 1.6 beta and my system is noticeably slower on *conservative* cpu gov and quadrant scores dropped clearly below 1500. Ondemand cpu gov seems to work ok but as I was alwaus on conservative I can not be abs.sure
I don't know if it is important but using voltage control app to check cpu function I see that:
a) cpu freq is wildly/unpredictably fluctuating with 1.6beta while this was not happening in 1.5 under conservative cpu gov,
and
1b) reported default voltage is different: for example with sema1.5 1200mhz had default 1275, now in 1.6beta without oc module 1000mhz is 1275 but with oc module 1200mhz have 1300mv by default.
Stratos,
could it be that a) something is broken in the new conservative cpu gov? , b) have you changed the default cpu voltage between v1.5 and v1.6beta?

GrNick said:
Unfortunately I can not post to dev section, so hopefully stratos will see my post here:
I had stock JVR with semaphore 1.5 (not v) on ext4 and everything was excellent with this brilliant kernel apart from the well known phone fc.
OC/UV was ok: quadrant scores were approx 1900-2400 on conservative cpu gov and 2500-3000 on ondemand gov.
Now, I flashed the 1.6 beta and my system is noticeably slower on *conservative* cpu gov and quadrant scores dropped clearly below 1500. Ondemand cpu gov seems to work ok but as I was alwaus on conservative I can not be abs.sure
I don't know if it is important but using voltage control app to check cpu function I see that:
a) cpu freq is wildly/unpredictably fluctuating with 1.6beta while this was not happening in 1.5 under conservative cpu gov,
and
1b) reported default voltage is different: for example with sema1.5 1200mhz had default 1275, now in 1.6beta without oc module 1000mhz is 1275 but with oc module 1200mhz have 1300mv by default.
Stratos,
could it be that a) something is broken in the new conservative cpu gov? , b) have you changed the default cpu voltage between v1.5 and v1.6beta?
Click to expand...
Click to collapse
Unfortunately I can not confirm your results. I just load the conservative governor and tested with and without overclocking. No problems here.
During benchmarking due to high load the frequency it's difficult to drop below the max. So, governor should not make the difference.
The uv value was the same in 1.5.0 (1300mv) for 1.2Ghz but it was wrongly displayed as 1275.
Thanks for you feedback. I will let you know if someone else report problems about the conservative governor.

Hey stratos, thanks for the clarification about cpu voltage.
Re cpu gov, I just did a nandroid restore and confirmed that conservative cpu gov works much better in 1.5
Any ideas on how to explore it further? There is definetely something different here.
I mean, its not just quadrant scores, its memento database loading instantly vs seconds of delay under cons cpu gov in 1.5 vs 1.6beta.
I will reflash again l8r tonight.
Anyhow, this kernel rocks! And I love the tun/netfilter module design.
Sent from my GT-I9000 using Tapatalk

Most efficient CPU Governor?

I am running Eclipse 1.3.8, and i have System Tuner Pro (obviously that doesn't matter, though). I keep the clock from 300mhz to 1.2 ghz. However, I can't seem to decide which governor is most efficient.
The following are the 4 that I can't decide between:
Hotplug
mot_hotplug
userspace
ondemand
Can anyone, from experience, say which one will be the most efficient at saving battery?

[Q] Best Governor/IO Scheduler/Voltage for best battery?

I'm currently on Zeus v7.01 with dianaV2.3+ kernel and I'm wondering what is the best combination of Governor/IO Scheduler/Voltage to obtain the most best battery life.
I'm not searching for best performance honestly, but instead a longer lasting phone. lol
I rarely play games, and smoothness is not a must for me (Nemus Launcher does the job, smoothest launcher ever!)
My current settings are:
CPU Frequency Tweaks
Max freq: 1000
Min freq: 100
DVFS enabled on boot
Voltage Tweak: -5
Governor: ondemandX
Io Scheduler: sio (Simple I/O)

You could try undervolting your phone,because i like performance and smoothness,my setup is like that:
Max CPU frequency:1300Mhz
Min CPU frequency:300Mhz
Governor:Smartassv2
I/O scheduler:deadline.
Sorry for useless stuff,but i like to share
My main agenda is to help, not gain thanks.

UniversalSS said:
You could try undervolting your phone,because i like performance and smoothness,my setup is like that:
Max CPU frequency:1300Mhz
Min CPU frequency:300Mhz
Governor:Smartassv2
I/O scheduler:deadline.
Sorry for useless stuff,but i like to share
My main agenda is to help, not gain thanks.
Click to expand...
Click to collapse
No no it's nice to share your experience!!
Might help others..
Hmm my phone is already UV... -5, if i decrease further wouldn't it be too low to cause instability?
And about IO Scheduler, i don't quite fully understand it.. which one drain least battery?

i am using 100-800 smartass2 sio and -7V without any problems.

[Q] Underclocking?

So I installed Topogigi's 2x ics rom and I found that I can't underclock the minimum cpu speed on a number of cpu speed tweaking apps including, cpu master, voltage control, no frills cpu control. Basically the maximum cpu speed is set to 1000mhz, and the minimum is set to 1000mhz which I can't change. When I used cyanogenmod 7 and the stock gingerbread rom, I could freely underclock the cpu. I was wondering whether this has anything to do with the cpu governer (which is hotplug on this rom) and/or the i/o scheduler.
Link to the rom I'm using:
http://forum.xda-developers.com/showthread.php?t=2007968
Thanks