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CPU time min threshold for CpuTimePerUidFreq

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Introduce a threshold to exclude small CPU time values in
CpuTimePerUidFreq. They come from more precise accounting in a BPF
program.

The threshold is 10 ms to match the behavior of the time_in_state BPF
predecessor. The reducation in data size is expected be at least 20%.

Bug: 157535126
Test: adb shell cmd stats pull-source 10010
Change-Id: Ia7f2a2ad71831387cffdd6db30da4ce501219d0e
This commit is contained in:
Rafal Slawik
2020-10-30 14:35:13 +00:00
parent e97f73dd91
commit a79cf88cb7
1 changed files with 8 additions and 1 deletions
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9
services/core/java/com/android/server/stats/pull/StatsPullAtomService.java
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@@ -247,6 +247,13 @@ public class StatsPullAtomService extends SystemService {
// 20% as a conservative estimate.
private static final int MAX_PROCSTATS_RAW_SHARD_SIZE = (int) (MAX_PROCSTATS_SHARD_SIZE * 1.20);
/**
* Threshold to filter out small CPU times at frequency per UID. Those small values appear
* because of more precise accounting in a BPF program. Discarding them reduces the data by at
* least 20% with negligible error.
*/
private static final int MIN_CPU_TIME_PER_UID_FREQ = 10;
private final Object mThermalLock = new Object();
@GuardedBy("mThermalLock")
private IThermalService mThermalService;
@@ -1509,7 +1516,7 @@ public class StatsPullAtomService extends SystemService {
int pullCpuTimePerUidFreqLocked(int atomTag, List<StatsEvent> pulledData) {
mCpuUidFreqTimeReader.readAbsolute((uid, cpuFreqTimeMs) -> {
for (int freqIndex = 0; freqIndex < cpuFreqTimeMs.length; ++freqIndex) {
if (cpuFreqTimeMs[freqIndex] != 0) {
if (cpuFreqTimeMs[freqIndex] >= MIN_CPU_TIME_PER_UID_FREQ) {
pulledData.add(FrameworkStatsLog.buildStatsEvent(
atomTag, uid, freqIndex, cpuFreqTimeMs[freqIndex]));
}