Increase session saving chunk size for much better performance.

Increasing the StoreSession chunk size from 1Msamples to 10Msamples
leads to massively faster session saving due to reduced overhead.

In some cases a 2x (or more) speed-up has been observed. A further increase
to, say, 100Msamples shows no further noticeable improvements.

This also has the additional benefit of generating fewer entries/files
within the sigrok session (*.sr) output/ZIP files, which can potentially
be beneficial for very long captures.

diff --git a/pv/storesession.cpp b/pv/storesession.cpp
index b0f33f4a7a2ae674f2253ca16bedf11362475dfb..52a6be34c490fe27cb9bcfb3cf263c5a47b530df 100644 (file)
--- a/pv/storesession.cpp
+++ b/pv/storesession.cpp
@@ -69,7 +69,7 @@ using sigrok::OutputFlag;
 
 namespace pv {
 
-const size_t StoreSession::BlockSize = 1024 * 1024;
+const size_t StoreSession::BlockSize = 10 * 1024 * 1024;
 
 StoreSession::StoreSession(const std::string &file_name,
        const shared_ptr<OutputFormat> &output_format,