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 f635fc387a59dc4156273ca0dd4d88602ca35a27..483d97b13304b337801066ad84a0ae5dcdb57e62 100644 (file)
--- 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 513b7dbd9412fdc03883e7c4991083551923df60..ba1db8e42cee554bc5778dba843dfd63713e9db1 100644 (file)
--- 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 97741ebf7b944a4c6507bd1a4e64c1d8128a5d5b..42c581d420122fd126fc9e7fb7d51b11f3b34648 100644 (file)
--- 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 0f067a47be1f8e2875467c976cd4424e616c046b..bd403605eae33e80b120894419aa6359495f76de 100644 (file)
--- 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);