The new Firefox OS reference phone is called the Flame. I have one that I’m using as my day-to-day phone, and as soon as I got it I found that the battery life was terrible — I use my phone very lightly, but the battery was draining in only 24 hours or so.

It turns out this was because a kernel daemon called ksmd (kernel samepage merging daemon) was constantly running and using about 3–7% of CPU. I detected this by running the following command which prints CPU usage stats for all running processes every five seconds.

adb shell top -m 5

ksmd doesn’t seem very useful for a device such as the Flame, and Alexandre Lissy kindly built me a new kernel with it disabled, which improved my battery life by at least 3x. Details are in the relevant bug.

It seems that plenty of other Flame users are not having problems with ksmd, but if your Flame’s battery life is poor it would be worth checking if this is the cause.

https://blog.mozilla.org/nnethercote/2014/07/15/poor-battery-life-on-the-flame-device/