From: Soeren Apel <redacted>
Date: Wed, 8 Feb 2017 19:33:48 +0000 (+0100)
Subject: Free unused segment memory after acquisition
X-Git-Tag: pulseview-0.4.0~198
X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=commitdiff_plain;h=5e6967cb2bcacbfb9e5b627becb6752621949998

Free unused segment memory after acquisition

Segments allocate chunks of MaxChunkSize bytes each.
Most likely, the last allocated chunk isn't fully used,
so there's memory going to waste. This patch fixes this
by allocating a chunk of the required size that replaces
the last standard chunk.
---

diff --git a/pv/data/segment.cpp b/pv/data/segment.cpp
index f635fc38..483d97b1 100644
--- a/pv/data/segment.cpp
+++ b/pv/data/segment.cpp
@@ -88,6 +88,21 @@ unsigned int Segment::unit_size() const
 	return unit_size_;
 }
 
+void Segment::free_unused_memory()
+{
+	lock_guard<recursive_mutex> lock(mutex_);
+
+	// No more data will come in, so re-create the last chunk accordingly
+	uint8_t* resized_chunk = new uint8_t[used_samples_ * unit_size_];
+	memcpy(resized_chunk, current_chunk_, used_samples_ * unit_size_);
+
+	delete[] current_chunk_;
+	current_chunk_ = resized_chunk;
+
+	data_chunks_.pop_back();
+	data_chunks_.push_back(resized_chunk);
+}
+
 void Segment::append_single_sample(void *data)
 {
 	lock_guard<recursive_mutex> lock(mutex_);
diff --git a/pv/data/segment.hpp b/pv/data/segment.hpp
index 513b7dbd..ba1db8e4 100644
--- a/pv/data/segment.hpp
+++ b/pv/data/segment.hpp
@@ -67,6 +67,8 @@ public:
 
 	unsigned int unit_size() const;
 
+	void free_unused_memory();
+
 protected:
 	void append_single_sample(void *data);
 	void append_samples(void *data, uint64_t samples);
diff --git a/pv/session.cpp b/pv/session.cpp
index 97741ebf..42c581d4 100644
--- a/pv/session.cpp
+++ b/pv/session.cpp
@@ -857,6 +857,9 @@ void Session::sample_thread_proc(function<void (const QString)> error_handler)
 		assert(0);
 	}
 
+	// Optimize memory usage
+	free_unused_memory();
+
 	// We now have unsaved data unless we just "captured" from a file
 	shared_ptr<devices::File> file_device =
 		dynamic_pointer_cast<devices::File>(device_);
@@ -868,6 +871,17 @@ void Session::sample_thread_proc(function<void (const QString)> error_handler)
 		error_handler(tr("Out of memory, acquisition stopped."));
 }
 
+void Session::free_unused_memory()
+{
+	for (shared_ptr<data::SignalData> data : all_signal_data_) {
+		const vector< shared_ptr<data::Segment> > segments = data->segments();
+
+		for (shared_ptr<data::Segment> segment : segments) {
+			segment->free_unused_memory();
+		}
+	}
+}
+
 void Session::feed_in_header()
 {
 	cur_samplerate_ = device_->read_config<uint64_t>(ConfigKey::SAMPLERATE);
diff --git a/pv/session.hpp b/pv/session.hpp
index 0f067a47..bd403605 100644
--- a/pv/session.hpp
+++ b/pv/session.hpp
@@ -182,6 +182,8 @@ private:
 private:
 	void sample_thread_proc(std::function<void (const QString)> error_handler);
 
+	void free_unused_memory();
+
 	void feed_in_header();
 
 	void feed_in_meta(std::shared_ptr<sigrok::Meta> meta);