[android-developers] Re: GC calls from other processes causing slowdown (?)

Is/was 2590 your process?

On Sunday, March 31, 2013 8:07:50 AM UTC+1, Jason wrote:

Hey folks,

So I'm in the midst of creating a game and I'm hitting some occasional slow down which "seems" to be a result of GC calls triggered by other processes on the device.  I have profiled my app and am 100% certain there are no allocations going on while the game is running, but in certain circumstances (i.e. most of the time) logcat is spewing out GC_CONCURRENT freed...blah blah entries.  Here's a typical output from the console:

03-30 23:58:58.868: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8758K/9224K, paused 5ms+3ms, total 29ms

03-30 23:59:05.970: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 408K, 6% free 8757K/9228K, paused 4ms+2ms, total 30ms

03-30 23:59:13.063: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8757K/9224K, paused 4ms+4ms, total 33ms

03-30 23:59:20.142: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8757K/9228K, paused 5ms+3ms, total 30ms

03-30 23:59:27.227: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8757K/9224K, paused 6ms+2ms, total 31ms

03-30 23:59:34.306: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8757K/9232K, paused 4ms+2ms, total 23ms

03-30 23:59:41.392: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8757K/9224K, paused 4ms+2ms, total 27ms

03-30 23:59:48.470: DEBUG/dalvikvm(2590): GC_CONCURRENT freed 407K, 6% free 8757K/9232K, paused 5ms+2ms, total 30ms

Now I have no idea which processes are to blame, but I did notice that when "other" events on the device occur it can lead to a spike in (I assume) CPU usage which causes a visible drop in frame rate in the game.

For example my wifi connection dropped out one time and the logs went crazy with other processes complaining about a lost connection and trying desperately to tell me about it.  This caused a fairly severe jolt in the game dropping the frame rate from 60fps to around 20fps for about a minute while everything settled down and got on with things.

I had noted on a previous thread a statement from Dianne Hackborn:

"as of 1.6 such GCs in a background process can not together take more than ~10% of the CPU from any foreground process that wants to run."

This sounds good, but I'm wondering if this is still the case as of 4.2.2?  I am seeing behavior that appears to indicate this may not the case.

Is there anything I can do to ensure other processes are not using more than 10% of CPU (or any number really)?  Or some other restrictions/priorities that might help alleviate this external resource usage?

Thanks,

Jason.

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