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POAndroid: Why does it take so long to start new activity?
 

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  1. POAndroid: Why does it take so long to start new activity?
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    <p>I have an Android activity <code>BrowseActivity</code> which load about 3000 records (@ about 100 bytes) from database into memory and show them in a <code>ListView</code>. It takes about 3 to 6 seconds in AVD to load, which is fine. </p> <p>The problem arises when I want to start a new activity from within this <code>BrowseActivity</code>. It takes about 30 seconds, even just to open the most trivial activity. Dalvik VM seems to do a LOT of garbage collecting for unknown reason. Please check <code>logcat</code> output below.</p> <pre><code>01-30 02:06:27.025: D/dalvikvm(553): GC_FOR_MALLOC freed 3889 objects / 221200 bytes in 45ms 01-30 02:06:28.234: D/dalvikvm(553): GC_FOR_MALLOC freed 2784 objects / 76864 bytes in 48ms 01-30 02:06:29.614: D/dalvikvm(553): GC_FOR_MALLOC freed 2665 objects / 70088 bytes in 64ms 01-30 02:06:30.915: D/BrowseActivity(553): Low memory status: false 01-30 02:06:30.915: D/BrowseActivity(553): Low memory threshold (KB): 16384 01-30 02:06:30.915: D/BrowseActivity(553): Memory available (KB): 451348 01-30 02:06:31.095: D/dalvikvm(553): GC_EXTERNAL_ALLOC freed 2711 objects / 85904 bytes in 62ms 01-30 02:06:49.705: D/dalvikvm(553): GC_FOR_MALLOC freed 8894 objects / 600272 bytes in 89ms 01-30 02:06:50.414: D/dalvikvm(553): GC_FOR_MALLOC freed 10757 objects / 730720 bytes in 68ms 01-30 02:06:51.105: D/dalvikvm(553): GC_FOR_MALLOC freed 10251 objects / 694864 bytes in 67ms ... and about 30 more garbage collection messages </code></pre> <p>I already experimented with lower number of records: 1 and 300. It results in a much fewer garbage collection messages (1 and 7, respectively) and a much faster activity load (1 and 6 seconds, respectively), but the memory availability difference is quite trivial:</p> <pre><code>01-30 02:03:35.295: D/BrowseActivity(491): Low memory status: false 01-30 02:03:35.295: D/BrowseActivity(491): Low memory threshold (KB): 16384 01-30 02:03:35.295: D/BrowseActivity(491): Memory available (KB): 453184 01-30 02:04:53.494: D/BrowseActivity(522): Low memory status: false 01-30 02:04:53.494: D/BrowseActivity(522): Low memory threshold (KB): 16384 01-30 02:04:53.494: D/BrowseActivity(522): Memory available (KB): 453152 </code></pre> <p>It seems that the slow activity load time is caused by GC overheads. My question is: Why does Dalvik VM does a lot of GC? Even with 3000 records, I believe it would only take top 500 KB in memory. If it's not about GC overheads, what's the other possible causes for this slow activity load?</p> <p>For the record, I logged the memory availability using the information provided by built-in class <a href="http://developer.android.com/reference/android/app/ActivityManager.MemoryInfo.html" rel="nofollow">ActivityManager.MemoryInfo</a>.</p>
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    1. CODo you invoke finalize before you switch? This apparently starts the GC http://developer.android.com/reference/android/app/Activity.html#ActivityLifecycle --- the life cycle doesn't say much about GC and memory management that I know of.
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    2. COIs loading 3 to 6 seconds slow? for 3k records?
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    3. CO@FaddishWorm No, I don't invoke finalize.
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