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Switch to static warning threshold when adopting.

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See rationale and details in inline comment block.

Test: adopt slow and fast SD cards
Bug: 29990216
Change-Id: I927d683db5e43216ee0837290ee4ca23a55a5dbb
This commit is contained in:
Jeff Sharkey
2016-10-05 11:21:22 -06:00
committed by Jeff Sharkey
parent 6cab381bc2
commit bd7adb9313
1 changed files with 33 additions and 10 deletions
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43
src/com/android/settings/deviceinfo/StorageWizardFormatProgress.java
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@@ -86,7 +86,6 @@ public class StorageWizardFormatProgress extends StorageWizardBase {
private volatile int mProgress = 20;
private volatile long mInternalBench;
private volatile long mPrivateBench;
@Override
@@ -98,11 +97,9 @@ public class StorageWizardFormatProgress extends StorageWizardBase {
storage.partitionPrivate(activity.mDisk.getId());
publishProgress(40);
mInternalBench = storage.benchmark(null);
publishProgress(60);
final VolumeInfo privateVol = activity.findFirstVolume(VolumeInfo.TYPE_PRIVATE);
mPrivateBench = storage.benchmark(privateVol.getId());
mPrivateBench /= 1000000;
// If we just adopted the device that had been providing
// physical storage, then automatically move storage to the
@@ -150,13 +147,39 @@ public class StorageWizardFormatProgress extends StorageWizardBase {
}
if (activity.mFormatPrivate) {
final float pct = (float) mInternalBench / (float) mPrivateBench;
Log.d(TAG, "New volume is " + pct + "x the speed of internal");
// When the adoptable storage feature originally launched, we
// benchmarked both internal storage and the newly adopted
// storage and we warned if the adopted device was less than
// 0.25x the speed of internal. (The goal was to help set user
// expectations and encourage use of devices comparable to
// internal storage performance.)
// To help set user expectations around device performance, we
// warn if the adopted media is 0.25x the speed of internal
// storage or slower.
if (Float.isNaN(pct) || pct < 0.25) {
// However, since then, internal storage has started moving from
// eMMC to UFS, which can significantly outperform adopted
// devices, causing the speed warning to always trigger. To
// mitigate this, we've switched to using a static threshold.
// The static threshold was derived by running the benchmark on
// a wide selection of SD cards from several vendors; here are
// some 50th percentile results from 20+ runs of each card:
// 8GB C4 40MB/s+: 3282ms
// 16GB C10 40MB/s+: 1881ms
// 32GB C10 40MB/s+: 2897ms
// 32GB U3 80MB/s+: 1595ms
// 32GB C10 80MB/s+: 1680ms
// 128GB U1 80MB/s+: 1532ms
// Thus a 2000ms static threshold strikes a reasonable balance
// to help us identify slower cards. Users can still proceed
// with these slower cards; we're just showing a warning.
// The above analysis was done using the "r1572:w1001:s285"
// benchmark, and it should be redone any time the benchmark
// changes.
Log.d(TAG, "New volume took " + mPrivateBench + "ms to run benchmark");
if (mPrivateBench > 2000) {
final SlowWarningFragment dialog = new SlowWarningFragment();
dialog.showAllowingStateLoss(activity.getFragmentManager(), TAG_SLOW_WARNING);
} else {