logd: prune maintain per-id watermark
Without this change LogBuffer::prune and LogBuffer::erase
contributes 16.7% and 1.79% respectively. With this change,
they contributes 3.06 and 2.33% respectively. Pruning is
performed roughly 1 in every 255 log entries, a periodic
tamer latency spike.
Bug: 23685592
Change-Id: I6ae1cf9f3559bca4cf448efe8bcb2b96a1914c54
diff --git a/logd/LogBuffer.cpp b/logd/LogBuffer.cpp
index 707527b..cdf5d08 100644
--- a/logd/LogBuffer.cpp
+++ b/logd/LogBuffer.cpp
@@ -109,6 +109,9 @@
}
log_id_for_each(i) {
+ mLastSet[i] = false;
+ mLast[i] = mLogElements.begin();
+
char key[PROP_NAME_MAX];
snprintf(key, sizeof(key), "%s.%s",
@@ -329,7 +332,15 @@
}
}
+ bool setLast = mLastSet[id] && (it == mLast[id]);
it = mLogElements.erase(it);
+ if (setLast) {
+ if (it == mLogElements.end()) { // unlikely
+ mLastSet[id] = false;
+ } else {
+ mLast[id] = it;
+ }
+ }
if (coalesce) {
stats.erase(element);
} else {
@@ -490,7 +501,8 @@
if (caller_uid != AID_ROOT) {
// Only here if clearAll condition (pruneRows == ULONG_MAX)
- for(it = mLogElements.begin(); it != mLogElements.end();) {
+ it = mLastSet[id] ? mLast[id] : mLogElements.begin();
+ while (it != mLogElements.end()) {
LogBufferElement *element = *it;
if ((element->getLogId() != id) || (element->getUid() != caller_uid)) {
@@ -498,6 +510,11 @@
continue;
}
+ if (!mLastSet[id] || ((*mLast[id])->getLogId() != id)) {
+ mLast[id] = it;
+ mLastSet[id] = true;
+ }
+
if (oldest && (oldest->mStart <= element->getSequence())) {
busy = true;
if (oldest->mTimeout.tv_sec || oldest->mTimeout.tv_nsec) {
@@ -566,7 +583,7 @@
bool kick = false;
bool leading = true;
- it = mLogElements.begin();
+ it = mLastSet[id] ? mLast[id] : mLogElements.begin();
// Perform at least one mandatory garbage collection cycle in following
// - clear leading chatty tags
// - coalesce chatty tags
@@ -615,6 +632,11 @@
continue;
}
+ if (leading && (!mLastSet[id] || ((*mLast[id])->getLogId() != id))) {
+ mLast[id] = it;
+ mLastSet[id] = true;
+ }
+
unsigned short dropped = element->getDropped();
// remove any leading drops
@@ -725,7 +747,7 @@
bool whitelist = false;
bool hasWhitelist = (id != LOG_ID_SECURITY) && mPrune.nice() && !clearAll;
- it = mLogElements.begin();
+ it = mLastSet[id] ? mLast[id] : mLogElements.begin();
while((pruneRows > 0) && (it != mLogElements.end())) {
LogBufferElement *element = *it;
@@ -734,6 +756,11 @@
continue;
}
+ if (!mLastSet[id] || ((*mLast[id])->getLogId() != id)) {
+ mLast[id] = it;
+ mLastSet[id] = true;
+ }
+
if (oldest && (oldest->mStart <= element->getSequence())) {
busy = true;
if (whitelist) {
@@ -764,7 +791,7 @@
// Do not save the whitelist if we are reader range limited
if (whitelist && (pruneRows > 0)) {
- it = mLogElements.begin();
+ it = mLastSet[id] ? mLast[id] : mLogElements.begin();
while((it != mLogElements.end()) && (pruneRows > 0)) {
LogBufferElement *element = *it;
@@ -773,6 +800,11 @@
continue;
}
+ if (!mLastSet[id] || ((*mLast[id])->getLogId() != id)) {
+ mLast[id] = it;
+ mLastSet[id] = true;
+ }
+
if (oldest && (oldest->mStart <= element->getSequence())) {
busy = true;
if (stats.sizes(id) > (2 * log_buffer_size(id))) {
diff --git a/logd/LogBuffer.h b/logd/LogBuffer.h
index 2667e78..03739c7 100644
--- a/logd/LogBuffer.h
+++ b/logd/LogBuffer.h
@@ -82,6 +82,9 @@
LogStatistics stats;
PruneList mPrune;
+ // watermark for last per log id
+ LogBufferElementCollection::iterator mLast[LOG_ID_MAX];
+ bool mLastSet[LOG_ID_MAX];
// watermark of any worst/chatty uid processing
typedef std::unordered_map<uid_t,
LogBufferElementCollection::iterator>