Switching SmartReflex on the fly?
 

Over the years, I've messed with various kernel-power settings and reached the conclusions (valid only for my particular device), that

- any voltage profile less than "ideal" seems to introduce problems when accessing microSD
- using SmartReflex on VDD1 and VDD2 results in better battery life, but precludes overclocking beyond 805MHz
- the phone is stable at 250-805MHz with SmartReflex on VDD1 and VDD2 and has been running that way for a year

Now, without SmartReflex on either VDD and using the ideal voltage profile, the phone is perfectly happy at 1000MHz and this provides a noticeable speed boost to the interface. I wouldn't have chosen to do this two years ago, but warranty is no longer relevant and I have a spare N900 anyway. So, fine, we'll overclock the hell out of it. When we need to, that is. Battery life is still a concern, so I'd still like the phone to spend most of its time in 250-805MHz with SR, but to toggle SR and give me 1000MHz (preemptively) when I require it.

I don't want to do this by issuing a "kernel-config load xxx" on every lock/unlock as that takes upwards of half a second to complete, introducing a degree of lag and arguably defeating the purpose of the exercise. But, it has only just dawned on me that I can avoid this by setting the "ideal" voltage profile as default, then overriding clock speed and SmartReflex settings using sysctl. For instance:

/usr/local/bin/smartreflex:

#!/bin/sh

case $1 in
"on")
echo "805000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
echo "250000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
echo "1" > /sys/power/sr_vdd1_autocomp
echo "1" > /sys/power/sr_vdd2_autocomp
;;

"off")
echo "0" > /sys/power/sr_vdd1_autocomp
echo "0" > /sys/power/sr_vdd2_autocomp
echo "1000000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
echo "250000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
;;

esac

It seems to work, so, is there any good reason not to do this? The logic I am thinking of employing here is not completely decided yet, but my thinking is that every time I unlock the phone, it'll be to load some sort of application and therefore, that I will benefit from full speed, briefly at least, every time I unlock the phone.

Maybe it needs to be coupled with a timer when we're on battery, because one of two situations will be true. If I unlocked the phone for short-term use, i.e. to read a message or check when my bus is coming, then it'll be relocked again after a minute or two, in which case that relocking can be used as the trigger for reenabling SmartReflex. The problem comes if I unlocked the phone to listen to music or take a phone call, and it perhaps remains unlocked for an hour or two. In this case, we'd want battery life over responsiveness of the user interface and should probably reconfigure accordingly.

So, I guess the logic that I am proposing can be described as:

- on phone unlock, disable SmartReflex and boost to 1000MHz. If on battery, set a timer to revert after five minutes.
- on phone lock, restrict to 805MHz and enable SmartReflex

and the rationale this is that it should improve the responsiveness of the phone / browser / etc. when first unlocking it and selecting or using an application. It is anticipated that this will not improve battery life as compared with leaving SmartReflex enabled, but that it will do a limited amount of harm. Am I making sense, or have I missed something? Comments, suggestions and improvements to this logic are invited...

Re: Switching SmartReflex on the fly?
 

Have you just stepped out of a time machine from 2010? With kernel power49 smart relex is now fixed and working up to 900MHz. Why not just compromise with 900MHz? Read the KP stable v49 thread for details. Also, no need for undervolting anymore, SR does it for you better than your empirical tests show.

The whole switching profiles thing is the basis for batterypatch. Go read the sources to find out more. Whether it works...well that is a major point of contention.

Re: Switching SmartReflex on the fly?
 

Ahem. To all intents and purposes, yes. I did what I was going to do as far as overclocking was concerned and have left it alone since, well, 2010. Guilty of upgrading to KP49 and not reading the fine manual until I wondered why it had lost a few speeds. The shipped configs with SR enabled defaulted to a max of 805, so this was what I presumed remained the safe limit. I'll play with SR and 900MHz. :-)

Still, my reason for doing this was not to reopen the debate about battery life, for which SR wins. Mostly I just want more responsiveness and I am starting feel less conservative about overclocking to attain it (never even actually tested 1100, I just might). There's also the point that if I'm going to buy a microSDXC and load it up with media, I'd like all the speed I can get when it comes to dealing with larger volumes of files/artists/whatever. I haven't undergone a scientific testing process of testing, but I did recently manage to get it to crash at 900MHz with SR enabled on VDD1, I think, and only tried 1000MHz without SR on a whim. If I can use 900MHz with SR that *may* provide a solution, but, I'm becoming tempted to say if I can have 1000, 1100, 1150... what by now is the compelling reason not to?

Battery life remains a concern, but I now carry a USB power brick and most people have microUSB chargers, so it's less of a worry than it was. Doesn't mean that I don't benefit from SR most of the time, but, I'd ditch it for 30 seconds for a 200-250MHz boost if I could sensibly identify circumstances in which to do so. Device life is less of a concern; I won't do anything that causes more than a couple of crashes. If I really do fry it, which I doubt, I have good backups and spare hardware. Warranty is no longer relevant. The only real concerns (to me) are stability, performance, and not wasting battery for the sake of it.

Thank you though for your input, I was not aware of this and will RTFM and do some further testing with SR at 900MHz.

Re: Switching SmartReflex on the fly?
 

If you want performance...

1. Do a complete reflash (unless you are convinced your setup is healthy)
2. Don't use widgetz
2. Install CSSU.
3. Install KP49.
4. Enable SR.
5. Change CPU speeds 500 low, 900 high.
6. Put swap on your SD card.
7. Apply some virtual memory tweaks.
8. Investigate compcache
9. Investigate swap reset script with cron/alarmd.

Do the above and your device will be as someone said, 'snappier than a crocodile at a penguin parade'.

// EDIT

Above is more or less my setup (except the swap on SD) and I see around 2 days battery life, and christ knows I am a serious fiddler.

Re: Switching SmartReflex on the fly?
 

How do you connect to WiFi APs w/ hidden SSID without ConnectNow Widget? "Browsing" from the statusbar plugin certainly doesn't work.

Re: Switching SmartReflex on the fly?
 

Once device is reflashed, does the order of above operations matter?

Where can one find information for 7, 8 & 9?

Re: Switching SmartReflex on the fly?
 

Recently,I wanted to create a dedicated partition for easy debian.Got lot of helpful members around.Even then I could not mount it to that partition.while going through this ,I had to flash my device.But I learnt how to use gparted,created a swap space of 384 MB on sd card.After that I have edited /etc/pmconfig enabling smartreflex,cpu to 900 following vi's advice.Believe me my device became too fast.I stopped caring about battery long ago ,though smart reflex gives me best battery life of approximately 8 hours(my battery is old).

Thank you.

Re: Switching SmartReflex on the fly?
 

xterm my son! Seriously I don't use any AP with hidden SSID, if I did I would just use kismet to figure out the SSID then take it from there. I actually use Queen Beecon to add a connect/disconnect button to the top right of the status bar area for my connect/disconnects.


No the order does not matter, neither does the method by which you achieve the aim. Virtual memory tweaks can be found with swappolube and here.

Compcache here.

As for the swap script, you will have to be a bit creative, I am sure Estel can chip in on that one.

Re: Switching SmartReflex on the fly?
 

Ok, so you actually also USE WIDGETS.

Re: Switching SmartReflex on the fly?
 

I think you will find I quite specifically typed "widgetz".