Why Your Battery Doesn't Last Long And What To Do About It
Sebastián 8. October 2007 :: activefile, battery
One of the most common complaints from the Nokia E50 users is the poor battery life. We’ve previously covered some tips on how to increase the battery life and this time we will look closer why our battery doesn’t last longer than a few days. Understanding the processes running on the phone will help us optimize the usage of our device and improve the battery life.
To do this, we will use a specific application called ActiveFile. ActiveFile is basically a common file explorer for the S60 devices but it has one extra feature which we will take advantage of – tracking the operative system activity. In this case we will use only the Memory Monitor which you can access from the main screen of ActiveFile, under the Options and Tools menu. So let’s see what’s going on in our phone:
Boot Up
As soon as the phone boots there are already several processes running (81 processes in our case) and the free executable memory is approximately 11.5MB. The number may vary based on how many 3rd party applications are running right after the start up. In this case we have 2 extra applications running – ScreenSnap to take screenshots and the previously mentioned ActiveFile with its feature to track memory usage. From this point, we can see the memory usage of common applications. The memory usage has straight effect on the power consumption. Let’s go through some of the most common applications to see how they may affect the battery life.
SMS interface
As we can see on the screenshot, simply going back from ActiveFile (leaving it running on the background, together with ScreenSnap) to the main screen, and entering the SMS application from the Active Standby screen, used almost 2MB of executable memory. No wonder why sending 40 messages per day drains some battery!
You could say this is too much for such a common application, but remember, we are running an entire OS(Operation System). There are a lot of subprocesses involved in something as simple as sending an SMS. For instance, T9 dictionary (that evaluates the written text) together with the link to the Contacts application certainly add up to the whole memory consumption.
Email interface
Let’s have a look at the email application. What you see on the screenshot is not the standard inbox but a 3rd party application called emoze. This application is always running on the background pushing my Gmail account to my phone. Only three apps running and we only have half of the executable memory free. At this point, some applications like Nokia Maps, QuickOffice or OfficeSuite won’t be loaded without closing one of the active applications (remember, this is valid for the Nokia E50 which has a total of 16MB memory; other devices like the E61 (21MB) or the E65 (24MB) can handle more applications at the same time).
Conclusions
1) As we can see, running a complex OS like Symbian S60 (which has a few million lines of code) has its advantages, but also some drawbacks. As in any OS, all apps running on Symbian leave some residual code behind them when they are closed. Think of it as your PC. If you leave it turned on for an entire week, eventually, even if your computer has no active applications running, it will be slower than if you do a reboot. For this reason, it is recommended to restart your phone at least once every couple of days.
2) We’ve seen memory usage of the common applications. Some applications I reviewed have not been specifically analysed here. To mention a few, Contacts uses approximately 800KB of memory, Notes uses a little more (depending on the amount of notes on your phone, on mine it’s approximately 1.2MB) and Agenda (a.k.a Calendar) uses surprisingly 600KB. Only Nokia Maps alone uses 1/3rd of the entire executable memory (in my test 4MB).
3) Ultimately, by tracking the memory usage, you’ll understand what’s going on inside your phone, and when to reboot it. ActiveFile doesn’t use too much memory and it’s a helpful and well designed application which runs without glitches on the E50. I hope it helps you to track your phone’s performance and battery life.
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Comments:
Comments are closed for this article. If you have questions check out the Nokia E50 Forum.
Awesome post, Jaro!
If I were a Symbian newbie it would definitely be helpful and make me calm about my E50 lacking RAM.
Keep up the good work!
Is it correct to correlate memory usage with battery comsuption? Having an app running on the background would surely use CPU resources and, thus, battery power. But I’m not sure that RAM has the same effect.
All in all, it’s a very interesting article.
Jgwong, in fact, the RAM quoted here is executable RAM (remember, the phone has three kinds of memory, SDRAM (a part of which is executable), NAND and the SD), and as you say, the need for more CPU resources mean more power… it’s a very different scenario for the OS to have plenty of executable RAM, than to be short on RAM and try all the time to keep all apps running without falling into a low memory error.
Also, remember that executable RAM needs power to be kept! We always overlook this, since we are used to have plenty of power from our power outlets on our places to maintain the info on the RAM of our computers, but on the phone, there’s no place except for the battery to take power to maintain executable RAM.
The idea behind is not to make a direct link between RAM and battery, but to use the info of RAM usage to approximately track the loads on the CPU, and hence, the battery power used. And of course, mainly, to evaluate the phone’s overall performance.
Best regards,
Sebastián.
RAM will use a constant (small) amount of power, unrelated to the amount of memory actually used.
But I suppose memory usage does correlate with CPU usage and thus with battery consumption.
I only try to get a feel for how much CPU processing my E50 does and how often the backlight is on. Closing programs after use and a fast activation of the default screen saver has worked for me.
[1] Peter, thanks but the post is written by Sebastián, not me :)
Hah, sorry – that’s how it looks when you have no time on your hand and just flip through links from your favourite feeds ;)
Anyway – great work, both of you guys :)
Regards,
P.
Not all operating systems drain memory while idle. Actually, only one does that – Windows. Restarting Symbian or any other OS won’t make your computer faster.
Peter, thanks for the compliment! Jaro made it “readable”, my english skills make some editing a necessity (unfortunately, my skills are not as good as I’d like), and Jaro took all that work… which, I think, is more difficult than writing the article :-D
Ante… I’ll have to disagree. First of all, I don’t know exactly what you mean by “drain memory when idle”... but even Linux has a lot of subprocesses and daemons even when the sistem is “idle” (despite swap partition, which is not executable). I/O between components (CPU to screen for example, for a screensaver), etc… all that is ran from executable memory.
And restarting your smartphone once in a while (and from my experiencie, I recommend once at least every couple of days, specifically for the E50) is a really old tip, that comes from Symbian S60v1, through S60v2 to S60v3. And is a recommendation for any OS indeed when the performance has slowed down notoriously even if there are no active tasks running.
I’m speaking not only from theory but from experience. After a week, even when idle my phone can only free up to 7MB. When I reboot it, I have 12MB+ of free memory. It’s a very different scenario for the Operative System to have plenty of spare memory to allocate, than having only some small space and having to reallocate code all the time in tasks priority order so you will not fall into an out of memory error.
Of course, you can disagree with me, but I think there’s no point arguing here, you can perfectly have a different experience… but above anything, you can take the advice or leave it my friend :-)
With best regards,
Sebastián.
Sebastian, well, not everything is black and white :) By default, Linux uses almost 99% of memory (I don’t know Symbian internals that much), but almost all of it is cache.
That means when you reboot your computer with Linux (and this probably works for Symbian too), you remove all the cache from the memory. Next time you start an application, you’ll have to upload it in memory again. If you don’t reboot it and leave the cache in memory, next time you start an application it will run from memory – no need for upload. Read/write needs more energy than idling.
Of course, if there is a broken application, everything is possible. That’s the problem with Windows – lot’s of memory leaks. That’s why it’s good to reboot windows now and then.
Other than that, rebooting systems (TV, computer, phone) drains more battery than just running it.
Don’t get me wrong, I’m not attacking you. You did a great job. I just wanted to point that full memory doesn’t always mean a bad thing – in 99% of cases it’s a good thing, and that those 5MB you lost/gained on reboot might be cache.
Just turning the phone off by night helps saving battery life too!!
Ante… I know that’s the way Linux, and Windows, and probably Mac works. The problem is that the E50 (Symbian S60) doesn’t work that way. When you exit an application, it clears it from the executable memory. But not completely, some code is left behind. At least for what I was able to trace… S60 code is not open. I traced processes according to their priority, i.e.: foreground, background, supervisor, etc., their capabilities and their presence in memory.
For what I was able to track, Symbian does not cache processes in order to make them load faster when you load them again. It loads them on memory according usage of applications, and it does leave residual code behind applications when you close them. The “residual code” I am talking about is that, residual code, not the entire task in the background on idle state. A quick check of the processes and tasks list, their changes in their priorities, gave me those conclusions. You can trace it yourself with Active File.
That’s why restarting the phone has been a common tip to improve performance since the old Symbian smartphones when they become excessively laggy.
If Symbian would cache processes, and we would have plenty of memory, certainly it would not be advisable to restart the phone. But we are talking about some applications (for example, Nokia Maps) that use 30% of executable memory. When you close Nokia Maps, it is not cached. But the free memory after closing Nokia Maps is, most of the time, less than what you had before starting Nokia Maps. Consider the same situation to all the individual applications used along the day (contacts, SMS, T9 predictive text, system log, email, perhaps the camera, etc.) and after two or three days of usage, the phone indeed can be laggy.
As I previously said, you can have a very different experience. But I certainly recommend you to track yourself processess and tasks, and see what happens. For example. Use the tasks list instead of processes to see if the application is indeed cleared or not (remember to refresh the list on Active File after exiting and app) happens. I give you my example:
Initial scenario: No active tasks (phone has not been restarted, it has been working since yesterday). Open Active File, start memory monitor. Free memory: 8200kB. Go back to active stand by (with Active File on the background, but its piority to the OS is foreground). Enter Messaging Application. Enter main inbox. Read a Message. Memory: 6800kB. Write answer. Save the answer as a draft. Back to Inbox. Read another message. Back to inbox. Go to drafts. Finish the draft and send it. Memory: 6300kB. Exit messaging application. Free memory: 7912kB.
As you can see, after closing, I don’t have my initial 8200kB, I have 200kB and something less. And the application is not active, as I can not see it listed on the application list, so it is not cached. I conclude it is not cached also because it is not loading faster than before, it takes the same time. Nevertheless, I have 200kB less of free executable memory.
For this experience, that has been carried on for a couple of weeks before writing the article, I made those conclusions and recommendations.
Perhaps you have a very different experience! It would be great if you could post your results, with the addition of firmware version, and detailed info. That way, we would be able to track changes on firmware updated too! (my phone has branded firmware, I’m running an old firmware version).
And of course, I don’t consider it an attack, just a different opinion. But it forces me to explain with much more detail my two weeks of tests with the phone to give a valid reason for the advices and conclusions. That’s why I recommend you to carry on the experience and see what happens along a couple of weeks! It would be very nice if you could, so we could compare experiences and even see if newer firmware improves these issues, and then I would update the article!
Best regards,
Sebastián.
Thanks for your input in the discussion guys! Lots of interesting information, I think we all learnt new things.
I have been suffering from the same battery life problems, several people have already discussed. To probe this further I removed all added applications, even Autolock 1.1. In effect the phone was as it came out of the box. Result No change in battery life. I then had a flash. I have been using a 20sec .m4a file, straight out of my iTunes library as a ringtone. Selecting one of the standard ringtone (nostalgia.aac) resulted in a doubling of battery life (~5 from ~2.5 days).
Any ideas as to why?
Regards
Andreas