Flush log files periodically
For low rate logs, disk bandwidth isn't the thing to worry about. The
real concern is how long data sits in memory before being written to
disk. Add a (configurable) threshold after which we flush data to disk
to bound the time.
Change-Id: Ia0be4a13a4840ec6b89c3ecafdeb3a1f1a82d4a2
diff --git a/aos/events/logging/logfile_utils.h b/aos/events/logging/logfile_utils.h
index 5fe45a5..2219a07 100644
--- a/aos/events/logging/logfile_utils.h
+++ b/aos/events/logging/logfile_utils.h
@@ -71,16 +71,22 @@
// Triggers a flush if there's enough data queued up.
//
// Steals the detached buffer from it.
- void QueueSizedFlatbuffer(flatbuffers::FlatBufferBuilder *fbb) {
- QueueSizedFlatbuffer(fbb->Release());
+ void QueueSizedFlatbuffer(flatbuffers::FlatBufferBuilder *fbb,
+ aos::monotonic_clock::time_point now) {
+ QueueSizedFlatbuffer(fbb->Release(), now);
}
// May steal the backing storage of buffer, or may leave it alone.
+ void QueueSizedFlatbuffer(flatbuffers::DetachedBuffer &&buffer,
+ aos::monotonic_clock::time_point now) {
+ QueueSizedFlatbuffer(std::move(buffer));
+ FlushAtThreshold(now);
+ }
+ // Unconditionally queues the buffer.
void QueueSizedFlatbuffer(flatbuffers::DetachedBuffer &&buffer) {
if (ran_out_of_space_) {
return;
}
encoder_->Encode(std::move(buffer));
- FlushAtThreshold();
}
// Queues up data in span. May copy or may write it to disk immediately.
@@ -159,8 +165,10 @@
ssize_t written, int iovec_size);
// Flushes data if we've reached the threshold to do that as part of normal
- // operation.
- void FlushAtThreshold();
+ // operation either due to the outstanding queued data, or because we have
+ // passed our flush period. now is the current time to save some CPU grabbing
+ // the current time. It just needs to be close.
+ void FlushAtThreshold(aos::monotonic_clock::time_point now);
std::string filename_;
std::unique_ptr<DetachedBufferEncoder> encoder_;
@@ -180,6 +188,9 @@
int total_write_count_ = 0;
int total_write_messages_ = 0;
int total_write_bytes_ = 0;
+
+ aos::monotonic_clock::time_point last_flush_time_ =
+ aos::monotonic_clock::min_time;
};
// Packes a message pointed to by the context into a MessageHeader.